Sunday, April 4, 2010

MAISONS SCOUDOUC HOUSES


MAISON SCOUDOUC HOUSE PLAN "A"

The Maison Scoudouc House Plan "A" is designed as a small 512 sq.ft. mini-home for a single person. This size is in line with the recommendation of 500 sq.ft. per person for the size for a basic superinsulated house. A single person needs much less enclosure of spaces. In this basic house the bathroom is the only interior room with a door. The home has a basic galley kitchen and open living room. Rather than having a bedroom, this design has a sleeping alcove with adjacent closets for clothing and drawers under the bed.

The super insulated construction techniques include ICF crawl space foundation, double exterior stud walls (R45), triple glazed casement windows sized for 16" o.c. stud spacing, and raised heel roof trusses (R60). See link to Construction Details for more information on materials and detailing.



MAISON SCOUDOUC HOUSE PLAN "B"

The Maison Scoudouc House Plan "B" design is the same small 512 sq.ft. mini-home for a single person, but with a 256 sq.ft. covered porch. The porch could also be enclosed as a heat sink during cold months and an expansion of living space during warm months. The floor plan is the same as the Plan "A" with the same features.

The superinsulated construction techniques include ICF crawl space foundation, double exterior stud walls (R45), triple glazed casement windows sized for 16" o.c. stud spacing, and raised heel roof trusses (R60). See link to Construction Details for more information on materials and detailing.



MAISON SCOUDOUC HOUSE PLAN "C"

The Maison Scoudouc House Plan "C" is designed as a small 624 sq.ft. one-bedroom home or retirement cottage for a single person or couple. The 144 sq.ft. covered porch is accessible from both the living room and the bedroom. In this basic house the bathroom is the only interior room with a door, but a door could be also be added at the bedroom for privacy. The plan contains a combination living / dining room with an L-shape kitchen, bedroom and full bath.

The superinsulated construction techniques include ICF crawl space foundation, double exterior stud walls (R45), triple glazed casement windows sized for 16" o.c. stud spacing, and raised heel roof trusses (R60). See link to Construction Details for more information on materials and detailing.




MAISON SCOUDOUC HOUSE PLAN "D"

The Maison Scoudouc House Plan "D" is designed as a small 688 sq.ft. one-bedroom home or retirement cottage for a single person or couple. The 176 sq.ft. covered porch is accessible from both the living room and the bedroom. In this basic house the bathroom is the only interior room with a door, but a door could be also be added at the bedroom for privacy. The plan contains a combination living / dining room with an L-shape kitchen, bedroom and full bath. In addition to the private bedroom, this design also has a sleeping alcove with adjacent storage closets and drawers to accommodate daytime napping and visitors.

The superinsulated construction techniques include ICF crawl space foundation, double exterior stud walls (R45), triple glazed casement windows sized for 16" o.c. stud spacing, and raised heel roof trusses (R60). See link to Construction Details for more information on materials and detailing.

Saturday, April 3, 2010

MAISON ST. THOMAS HOUSE


Maison St. Thomas House was designed for a friend in Nova Scotia to be built into a hillside overlooking the Bay of Fundy. The concept was to build a small one bedroom house (960 sq.ft.) with both a southerly and easterly view. Originally, the house was not designed to super insulated principles, but has been modified - more insulation, triple pane windows, HRV ventilator. Materials and detailing would be similar those shown for the Maisons Cocagne and Grande-Digue Houses in earlier posts (see Archives and Construction Details in links).

The upper level of the Maison St. Thomas House is the public level of the home. the entry foyer can serve as both closet and pantry. The upper level plan is a large open space composed of the living room area and a kitchen area with a table built into the kitchen cabinetry. The wood stove would be a pellet stove with an outside combustion air source (a must in superinsulated houses) to be used for backup and/or tempered heating.

This is a similar upper level floor plan, but with an L-kitchen with separate table and chairs for dining. Wood stove would follow comments above or could be replaced with a few baseboard heaters. The projected heating load would be reduced by the super insulated features where supplemental heat demand would be low. Ground source heat pump could be overkill as the demand is so low, but a heatpump water heater may have potential for hydronic or fancoil heating.


The lower level of the Maison St. Thomas House is the private area of the home containing he bedroom and bathroom. This level would be sheltered by the earth on the west and north elevations, and open to a walkout patio or garden on the south and east elevations. The south and east patio areas of the lower level could also have a covered porch if so desired.

MAISON GRANDE-DIGUE HOUSE - Exterior Deck

The exterior decking of the Maison Grande-Digue House can be done in any of several porch decking techniques. It is critical however that the deck framing be spaced from the building to prevent rot. All structural framing members should be topped with strips of asphaltic, water resistant building paper or ice shield. Materials shown are treated materials using appropriate fasteners for the treatment used.

MAISON GRANDE-DIGUE HOUSE - Foundation


Maison Grande-Digue House is designed with double 2x4 insulated, exterior stud walls @ 24" o.c. separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior partition walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier.

Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking.

Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above is required to carry the loads to the foundation. Details for optional balloon framing and openings are provided in the links and will be discussed later.

The Maison Grande-Digue House foundation walls are formed using LOGIX insulated concrete forms. While not a fan of rigid insulation, insulated concrete forms do have their place in the design of a foundation. The two layers of insulation used in the ICF system provides R20 insulation for the basement plus facilitates installation of finishes both inside and outside as well as easing reinforcing placement. The concrete foundation walls also create an effective vapor barrier. Care should be taken in laying out the exterior dimensions of the building and height of basement walls to match the dimension of standard ICF components (standard LOGIX block is 16" high x 48" long x depth desired). The 12" x 24" footings are the standard architectural overkill. Adjustments are feasible based upon engineering for local soils and conditions.

As mentioned in an earlier posting, crawl space and slab-on-grade foundations are also feasible, but space must be made on upper floors for mechanical equipment. See links to construction details for additional details and foundation systems.


MAISON GRANDE-DIGUE HOUSE - Roof


Roof trusses at the main building block of Maison Grande-Digue House are parallel chord trusses to allow for 18 inches of glass fiber batt insulation (R60). The roof trusses are installed at 24 inches on center in line with wall studs below. 6-mil vapor barrier is attached to the bottom chord of the truss. Gypsum wallboard or other desired finish is attached to the truss chords on 1x4 furring strips at 16 inch on center perpendicular to the trusses.

The benefits of installing radiant barriers are still in question. If used, I would recommend attaching the radiant barrier taping all joints to the bottom chord of the trusses after installing the vapor barrier, but prior to installation of the furring strips.

Roofing material is TRACC Moderne Slate roof shingles over ice shield underlayment. This is a 50-year roofing material made locally from recycled materials capable of withstanding a 175 mph wind driven rain. This is a very important feature on the Northumberland Strait where northeasters are not uncommon. The roofing sheds snow easily so consideration must be given to sliding snow in our climate. The roofing also works well for a rainwater collection system (guttering not shown).

Maison Grande-Digue House is designed with double 2x4 insulated, exterior stud walls @ 24" o.c. separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier.

Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking.

Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above and below is required to carry the loads to the foundation.

Details for optional balloon framing and openings are provided in the links and will be discussed later.

MAISON GRANDE-DIGUE HOUSE - Foundation @ Root Cellar

The foundation walls at the root cellar of the Maison Grande-Digue House are constructed using LOGIX insulated concrete forms. While not a fan of rigid insulation, insulated concrete forms do have their place in the design of a foundation and in particular a root cellar. The two layers of insulation used in the ICF system provides R20 insulation for the basement plus facilitates installation of finishes both inside and outside. The concrete foundation walls also create an effective air and vapor barrier.

Being as this is a root cellar, it is necessary for a cool, damp environment to be created. The floor of the cellar therefore is an exposed earthen surface. PVC vents are installed to control the temperature and humidity of the cellar.

The ceiling framing of the root cellar must be isolated from the moisture generated in the cellar and insulated from the cooler temperatures of the cellar. The 6-mil vapor barrier is applied to the bottom flange of the floor joist, then covered with furring strips and the cellar finish.

MAISON GRANDE-DIGUE HOUSE - Roof @ Kitchen Extension

Roof trusses at kitchen extension are raised heel trusses to allow for 18 inches of glass fiber batt or blown insulation (R60). The roof trusses are installed at 24 inches on center in line with wall studs below. 6-mil vapor barrier is attached to the bottom chord of the truss. Gypsum wallboard or other desired finish is attached to the truss chords on 1x4 furring strips at 16 inch on center perpendicular to the trusses.

The benefits of installing radiant barriers are still in question. If used, I would recommend attaching the radiant barrier taping all joints to the bottom chord of the trusses after installing the vapor barrier, but prior to installation of the furring strips.

Roofing material is TRACC Moderne Slate roof shingles over ice shield underlayment. This is a 50-year roofing material made locally from recycled materials capable of withstanding a 175 mph wind driven rain. This is a very important feature on the Northumberland Strait where northeasters are not uncommon. The roofing sheds snow easily so consideration must be given to sliding snow in our climate. The roofing also works well for a rainwater collection system (guttering not shown).

Maison Grande-Digue House is designed with double 2x4 insulated, exterior stud walls @ 24" o.c. separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier.

Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking.

Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks.

Details for optional balloon framing and openings are provided in the links and will be discussed later.

MAISON GRANDE-DIGUE HOUSE - Second Floor

SECOND FLOOR PLAN

Maison Grande-Digue House second floor plan features two bedrooms under a sheltering roof with central full bath under a roof dormer. Attic areas would be accessible for additional storage. As mentioned previously, these homes were originally built with finishing of the second floor as an option.

The exterior gable end walls continue the double 2x4 stud walls from below. Casement windows are chosen to fit into the stud spacing to reduce framing. Final finishes and detailing to be selected by owner.

The main building component is framed with parallel chord trusses to allow for high level of insulation.

See column at left for link to architectural detailing.

MAISON GRANDE-DIGUE HOUSE - First Floor

FIRST FLOOR PLAN

Maison Grande-Digue House has a compact first floor floor plan featuring a living room, kitchen / dining space, full bath, bedroom and den. Externally, the home is shown with a wrapping deck connecting entries to living room and kitchen.

The main floor bedroom would facilitate use of the home as a young couple, family or retired couple. The den could be used as a second small bedroom, guest room, sewing room, etc.

The exterior walls are fully insulated, double 2x4 stud walls @ 24" o.c. (16" o.c. spacing may be required in high wind areas or as a preference of the owner). Triple paned casement window units are sized to fit into the stud spacing to reduce additional framing (OVE engineering). Final finishes and detailing would be decided by the owner.

More specific detailing can be found in the details links provided in the column at left.

MAISON GRANDE-DIGUE HOUSE - Basement

BASEMENT PLAN

The Maison Grande-Digue House is designed with an unfinished full basement with a root cellar. With the exception of the mechanical room and stairs, the space can be used as needed by the owners for storage, laundry or hobbies.

The basement walls are constructed using insulated concrete forms (ICF) manufactured by LOGIX.

Specific detailing can be found in the detail links located in the left column.

MAISON GRANDE-DIGUE HOUSE


The Maison Grande-Digue House is a house style that can be found in many communities throughout Canada and North America. It was built after WWII in response to housing needs for returning veterans and their families. It is included as a prototype for superinsulated housing for its simplicity and affordability. In contrast to the Cocagne House, this prototype design incorporates a sheltering roof for the second floor. Surprisingly, the floor space is about the same. When originally built, the finishing of the second floor to include bedrooms and second bath was marketed as an option. A couple could purchase an affordable home and finish the upper floor as their family grew, but revert to the main level as they aged. The homes were often constructed in developments rather than individually. Over the years these home were modified with additions or shed roofs. The homes were individualized by special architectural detailing, materials and landscaping.

The house presented in this blog is built on a full basement with two bedrooms and a bath on the second floor. It could also be built on a crawl space or slab-on-grade foundation. It could also be built as only a one story house with a trussed roof.

Thursday, February 25, 2010

Optimium-Value Engineering (OVE)

This may be a good time to mention the subject of Optimum-Value Engineering (OVE) as it offers a method of framing that meets the structural needs of the building while reducing the amount of lumber used. Joseph Lstiburek's article The Future of Framing Is Here in the October / November 2005 issue of Fine Homebuilding magazine provides a good overview of this technique. Additional interesting OVE links are provided on the side panel under INTERESTING RESOURCES.

OVE is a good option to employ as the super insulated exterior walls are created by using two spaced stud walls. The framing techniques use common building practices with some modifications that would need some retraining of traditional framing crews. Not all the practices need to be Incorporated into the framing, i.e. a hybrid system can also be used. Courses need to be developed and offered at our provincial community colleges to train existing and future carpenters. Before materials are ordered and framing commences, the contractor and crews need to develop a plan of action so that everyone on the job site knows what is expected. Local building officials also need to contacted and buy into the OVE techniques to be used prior to framing so no surprises occur once work begins. As with all framing, unique conditions may require some specialized engineering. The designs I am offering attempt to make the framing as simple and straight forward as possible, however, beams, joists and lintels need to be verified by sound engineering.

Maison Cocagne House employs various OVE framing techniques in : two stud corners (see CONSTRUCTION DETAIL link Q. Corner Framing), properly sized window and door headers, stacked framing, single top plates, floating corners, etc. Windows are sized to fit within the 16" o.c. stud spacing. Allowances need to be provided for the 1/2 inch plywood boxes that surround the window opening plus rough opening clearance. The 16" o.c. spacing of the Maison Cocagne House super insulated stud walls accommodates 29-inch wide windows (30 1/2 inches between every second stud minus 1/2" each side for plywood box minus 1/4" play each side equals 29 inches). Spacing the super insulated stud walls at 24" o.c. would accommodate 21-inch wide windows (22 1/2 inches between studs minus 1/2" each side for plywood box minus 1/4" play each side equals 21 inches).

Saturday, February 20, 2010

MAISON COCAGNE HOUSE - Roof @ Attics Details



Roof trusses at attic (north) wall are parallel chord trusses to allow for 18 inches of glass fiber batt insulation (R60). The roof trusses are installed at 16 inches on center in line with wall studs below. 6-mil vapor barrier is attached to the bottom chord of the truss. Gypsum wallboard or other desired finish is attached to the truss chords on 1x4 furring strips at 16 inch on center perpendicular to the trusses.

The benefits of installing radiant barriers are still in question. If used, I would recommend attaching the radiant barrier taping all joints to the bottom chord of the trusses after installing the vapor barrier, but prior to installation of the furring strips.

Roofing material is TRACC Moderne Slate roof shingles over ice shield underlayment. This is a 50-year roofing material made locally from recycled materials capable of withstanding a 175 mph wind driven rain. This is a very important feature on the Northumberland Strait where northeasters are not uncommon. The roofing sheds snow easily so consideration must be given to sliding snow in our climate. The roofing also works well for a rainwater collection system (guttering not shown).

Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above and below is required to carry the loads to the foundation. Details for optional balloon framing and openings are provided in the links and will be discussed later.

MAISON COCAGNE HOUSE - Roof @ Bedroom Details


Roof trusses at bedroom (south) walls are raised heel trusses to allow for 18 inches of glass fiber batt or blown insulation (R60). The roof trusses are installed at 16 inches on center in line with wall studs below. 6-mil vapor barrier is attached to the bottom chord of the truss. Gypsum wallboard or other desired finish is attached to the truss chords on 1x4 furring strips at 16 inch on center perpendicular to the trusses.

The benefits of installing radiant barriers are still in question. If used, I would recommend attaching the radiant barrier taping all joints to the bottom chord of the trusses after installing the vapor barrier, but prior to installation of the furring strips.

Roofing material is TRACC Moderne Slate roof shingles over ice shield underlayment. This is a 50-year roofing material made locally from recycled materials capable of withstanding a 175 mph wind driven rain. This is a very important feature on the Northumberland Strait where northeasters are not uncommon. The roofing sheds snow easily so consideration must be given to sliding snow in our climate. The roofing also works well for a rainwater collection system (guttering not shown).

Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. Details for optional balloon framing and openings are provided in the links and will be discussed later.

MAISON COCAGNE HOUSE - Second Floor Details


Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above and below is required to carry the loads to the foundation. Details for optional balloon framing and openings are provided in the links and will be discussed later.

MAISON COCAGNE HOUSE - Basement / First Floor Details


Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Red dashed line shows location of the 6-mil vapor barrier in the wall system. Red dots show locations where barrier is sealed with acoustical caulking.Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. The design allows for the walls to be framed and insulated on the floors and lifted in place using wall jacks. A perimeter truss with 2x4 vertical blocking in line with the 2x4 wall studs above is required to carry the loads to the foundation. Details for optional balloon framing and openings are provided in the links and will be discussed later.

The foundation is formed using LOGIX insulated concrete forms. While not a fan of rigid insulation, insulated concrete forms do have their place in the design of a foundation. The two layers of insulation used in the ICF system provides R20 insulation for the basement plus facilitates installation of finishes both inside and outside as well as easing reinforcing placement. The concrete foundation walls also create an effective vapor barrier. Care should be taken in laying out the exterior dimensions of the building and height of basement walls to match the dimension of standard ICF components (standard LOGIX block is 16" high x 48" long x depth desired). The 12" x 24" footings are the standard architectural overkill. Adjustments are feasible based upon engineering for local soils and conditions.

As mentioned in an earlier posting, crawl space and slab-on-grade foundations are also feasible, but space must be made on upper floors for mechanical equipment. See links to construction details for additional details and foundation systems.

Monday, February 15, 2010

MAISON COCAGNE HOUSE - Second Floor




SECOND FLOOR

Bedroom 1 14' x 15'
Bedroom 2 14' x 15'
Full Bathroom 8' x 7'
Stair/Hall 8' x 17'8
Attics (2) 14' x 8' ea

745 sf (outside dimension)
650 sf (inside heated space)



The Second Floor of the Maison Cocagne House is designed to be the private area of the house. The main components are two bedroom areas separated by a bathroom/stair core. Adjacent to the bedrooms are attic spaces with sloped roofs. The core walls are framed as double stud walls to accommodate the heat recovery ductwork that will be discussed later. These spaces make up the thermal envelope of the main house. The bathroom is designed as a full bath located in a dormer. Cost reduction could be achieved by constructing the house with a full bathroom on the main floor and a compact 1/2 bath at the second floor (negates need for dormer). Finishes and final furnishing arrangement of areas are up to the occupant.

Windows would be high efficiency, triple glazed casements.

Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. Tongue & groove sheathing can also be used at outside stud walls to facilitate insulation installation. Details for air-tightness and openings are provided in the links and will be discussed later.

MAISON COCAGNE HOUSE - First Floor




FIRST FLOOR

Living/Dining 14' x 22'
Kitchen 14' x 15'
Laundry/Pantry 14' x 7'
3/4 Bathroom 8' x 7
Stair/Hall 8' x 17'8
Enclosed Porches (2) 14' x 8

990 sf (outside dimension)
860 sf (inside heated space)




The First Floor of the Maison Cocagne House is designed to be the public area of the house. The main components are a living/dining area and a kitchen/laundry/pantry area separated by a bathroom/stair core. The core walls are framed as double stud walls to accommodate the heat recovery ductwork that will be discussed later. These spaces make up the thermal envelope of the main house. The bathroom is designed as a 3/4 bath, but could also be a 1/2 bath. Finishes and final furnishing arrangement of areas are up to the occupant.

The house is accessed through a central open porch and two enclosed porches that would act as thermal collectors during cold months and as expanded living area during warm months. These porches could also be designed as open porches if the occupant so desired. There is also a secondary rear entrance from the laundry/pantry.

Windows of the main house would be high efficiency, triple glazed casements, double glazed casement and fixed windows at the porches. Doors would also be selected for high efficiency.

Maison Cocagne House is designed with double 2x4 insulated, exterior stud walls separated by a 3-1/2 inch fully insulated space to isolate the exterior walls from thermal bridging. The outside double stud walls would be erected prior to construction and erection of the interior stud walls. The inside stud walls are designed to be load bearing while the outside stud walls are designed to carry the exterior finish. The cold side of the inside stud wall is completely covered in a 6 mil vapor barrier then sheathed with 1/2 inch CDX plywood sheathing to provide lateral bracing as well as protect the vapor barrier. Experience has shown that the vapor barrier can be safely installed inside the wall as long as 2/3 of the insulation is on the cold side of the barrier. Locating the vapor barrier at the cold side of the inside stud wall allows for installation of electric without penetrating the vapor barrier. The cold side of the outside stud wall is sheathed with 1/2 inch fiberboard sheathing, then covered with house wrap. Tongue & groove sheathing can also be used at outside stud walls to facilitate insulation installation. Details for air-tightness and openings are provided in the links and will be discussed later.

MAISON COCAGNE HOUSE - Basement Plan




BASEMENT

Basement Room 14' x 22'
Storage Room 14' x 14'
Root Cellar 14' x 7'
Mechanical 8' x 7'
Stair/Hall 8' x 16'8
Cistern Rooms (2) 13' x 7' ea

990 sf (outside dimension)
760 sf (inside tempered spaces)





Maison Cocagne House is designed with a full basement using LOGIX insulated concrete forms (ICF). The full basement option was selected primarily due to the climate of New Brunswick. With our winter snow loads, it is desirable to have the first floor level several feet above finish grade. Local codes require footings to be 48 inches below finish grade to accommodate our frost depth. An additional two feet of foundation wall and excavation allows for the full basement design. The full basement also provides additional storage space, room for mechanical equipment, and the potential of a root cellar. The foundation could also have been designed using crawl space or slab-on-grade construction, but mechanical space would need to be provided on upper floors.

An added feature of the Maison Cocagne House are full basements under the enclosed south porches to house cisterns for rain water collection. An open porch design could have been designed on pier foundations with the rain water cisterns sited externally.

Tuesday, February 2, 2010

MAISON COCAGNE HOUSE - Elevations

SECOND FLOOR 745 sf (650 heated)
Bedroom 1 14' x 15'
Bedroom 2 14' x 15'
Full Bathroom 8' x 7'
Stair/Hall 8' x 17'8
Attics (2) 14' x 8' ea

FIRST FLOOR 990 sf (860 heated)
Living/Dining 14' x 22'
Kitchen 14' x 15'
Laundry/Pantry 14' x 7'
3/4 Bathroom 8' x 7
Stair/Hall 8' x 17'8
Enclosed Porches (2) 14' x 8

BASEMENT 990 sf (760 tempered)
Basement Room 14' x 22'
Storage Room 14' x 14'
Root Cellar 14' x 7'
Mechanical 8' x 7'
Stair/Hall 8' x 16'8
Cistern Rooms (2) 13' x 7' ea

Total Area 1745 sf
Total heated area 1510 sf

Footprint 40' x 32'

Maison Cocagne House is a design style commonly found in the Canada Maritime provinces - a simple rectangular form with a distinctive central dormer. Historically, houses of this style were often built as 1-1/2 story buildings incorporating a timber H-frame structural system. Maison Cocagne House is a stud framed 2-story building with an attached 1-story lean to at the north elevation. The thermal envelope of the house is defined as the space from the basement floor to the 2-story ceiling and 1-story roof within the basement and the exterior walls of the main house excluding the porches (21,620 cf).

Traditionally, buildings of this style were built either with or without open or enclosed porches. The first and second floors (excluding the enclosed porches) are heated; the basement (excluding the root cellar and cistern rooms) is tempered. The unheated, enclosed porches of the Maison Cocagne House are designed to act as solariums outside the thermal envelope of the main superinsulated house. The concept is to provide spaces to capture solar heat gain during the cold winter months and to reduce winter impact on the thermal envelope. The building can be opened to the porches during hours of daytime solar gain, but closed during nighttime heat loss. The porches also allow for the expansion of the kitchen and living room activity spaces during the warm summer months.

Maison Cocagne House was designed to incorporate, to the greatest extent possible, locally manufactured and/or Canadian products that use the least amount of embodied energy in composition and manufacturing. While striving to achieve the best thermal performance, material and system choices favored readily available skill levels and access to local materials and manufacturers.

Basement Walls: 12-inch LOGIX insulated concrete form (ICF) walls (2-inch XPS under floors)
Provide R20 rigid insulation for the tempered basement spaces.

Exterior Walls: 12-inch double stud walls with full thick ROXUL mineral fiber batts
Provide R45 insulation without thermal bridging.
Use optimum value engineering (OVE) framing techniques to reduce materials.
Use local forestry products and a Canadian insulation material.

Roofs: Raised heel roof trusses (main roof) & 24-inch parallel chord trusses (lean to)
Provide R60 up to R80 insulation.

Windows and Doors: Best product available from local manufacturers.
Triple glazed casement windows at thermal envelope openings.
Double glazed casement & fixed windows at porches.

Finishes: Best products available from local manufacturers to resist maritime climate.
Moderne-Slate by TRACC roofing shingles - 50 yr warrant / 175 mph uplift resistance.
Fibre-cement siding, but others are also appropriate.

Further discussions and illustrations of building materials and construction details will follow in later postings.

Monday, February 1, 2010

HEAT LOSS, HEAT GAIN & SUPERINSULATION

This will be my last post dedicated to background technical information, but is necessary to understand why a superinsulated house is superior to an insulated house. Simply put, a home gains heat and loses heat. If the home gains more heat than it loses, then we need to open the windows and/or air-condition. If the home loses more heat than it gains, then we need to shut the windows and turn on the furnace or other source of heat. The amount of heat and the length of year heat is required is referred to as the heating season. Superinsulation design will reduce the amount of heat required each day as well as shorten the heating season.

HEAT LOSS

Every house loses heat when the outside temeprature is lower than the inside temperature, always moving from warm to cold. Home heat is lost by three basic mechanisms:

1. Conduction - heat loss through materials and assemblies.

Most homes built in the past, as well as today, only incorporate the level of insulation and construction detailing that is "commonly practiced" or required by building codes. Superinsulation techniques reduce the amount of conductive heat loss by the intentional application of high levels of insulation (R40 or greater in walls / R60 in ceilings), reduction or elimination of thermal bridging in the structural framing, and installation of energy efficient doors,windows and storm doors, etc.

2. Infiltration - heat loss through air gaps.

Air-infiltration can often be the largest component of overall heat loss. Most houses built in the past, and unfortunately most today, did not fully address the need to reduce the amount of air infiltration for a multitude of reasons - "a house needs to breathe" or "don't worry, we'll put in a larger furnace" or "wood is cheap". Superinsulation techniques reduce the amount of infiltration heat loss by the design and installation of a complete, air-tight vapor barrier around the home's thermal envelope reducing air-infiltration to a minimum.

3. Ventilation - heat loss through exhausting warm air out of the house and cold intake replacement air into the house through bathroom vents, rangehoods, dryers, etc.

Superinsulation techniques reduce the potentially significant amount of ventilation heat loss by replacing traditional ventilation systems with heat recovery ventilators (HRV) that uses the warm exhaust air to preheat the incoming fresh air. This is critically important to provide a controlled source of fresh air in the air-tight environment of the thermal envelope.
In milder climates, exhaust-only ventilation system can use air-to-water heatpumps to transfer warmed exhaust air to heat domestic water and hydronic space heating.


Total Heat Loss Coefficent (HLC) is the heat loss rate for each degree of temperature difference between the inside air of the thermal envelope and the outside air measured in Btu per hour per degree Fahrenheit (Btu/h-°F). It the total sum of heat loss through all building components (walls, windows, doors, ceilings, basement walls, floor,etc.) due to conduction, infiltaration and ventilation. When multiplied by the indoor/outdoor temperature differential, it will provide the total home heat loss, but only for a point in time.


HEAT GAIN

Superinsulation design does not by itself increase or decrease heat gain mechanisms, but by intentional construction and design techniuqes takes full advantage of heat gain mechanisms to increase the home's energy efficiency and to reduce the home's heating load. While a home in a cold climate is losing heat through the heat loss mechanisms mentioned above, it is also gaining heat through three basic mechanisms:

1. Intrinsic heat gain is the embodied heat source produced from processes and activities occurring within the home - lighting, cooking, bathing, hair drying, human metabolism, appliances, refrigeration, etc. In a non-superinsulated home, most of the intrinsic heat is insignificant in comparison to or lost though high levels of conductive, infiltration and ventilation heat loss. In a superinsulated home, intrinsic heat sources are available for the heating of the home. The level of intrinsic heat gain available will vary depending on the activities occurring and when they occur, e.g. a television generates intrinsic heat, but only when it's in use. In a typical home, intrinsic heat can amount to between 2000-3000 Btu per hour.

2. Solar heat gain though either passive design or active collection systems can add significant heat gain depending upon the latitude of the home, the time of year, the amount of sunshine and cloud cover, the orientation of windows and the amount of shading. Maximum solar heat gain is typically received at midday between 10 am and 2 pm. While advantageous to receive this 'free' solar heat gain, it is not an imperative to successful superinsulated design.

3. Auxiliary heat gain is simply the the additional heat required through some controllable heat source to maintain comfort, i.e. the difference bewteen the home heat loss and the sum of the intrinsic heat gain and solar heat gain. The amount of auxiliary heat required will vary throughout the heating season and during each day. In superinsulated homes, the auxiliary heat gain requirement is so reduced, it is often a problem to design a heating system that is small enough to provide the required auxiliary heat.


BALANCE-POINT TEMPERATURE

The balance-point temperature (B-PT) is the outdoor temperature at which the total heat loss (HLC) equals the intrinsic heat plus the solar heat gains. When the outdoor temperature is at or above the B-PT, no auxiliary heat is required.

BP = Ti - [intrinsic heat input + solar heat input] / HLC

The balance-point temperature will vary throughout the day as the intrinsic and solar heat gains vary. Since superinsulated homes have a lower heat loss coefficient (HLC), they tend to have a much lower balance-point temperature (B-PT) even without solar heat gain. Factor in solar heat gain and the B-PT falls even further.

Typical heat loss / heat gain calculations used for mechanical equipment sizing assumes an average 65°F balance-point temperature as most homes have lower levels of insulation, are prone to air-leak infiltration and have exhaust-only ventilation systems.

In a superinsulated home with higher levels of insulation, air-tight construction and controlled heat recovery ventilation, the average balance-point temperature could be 42°F or even lower. This reduced B-PT can dramatically reduce the number of degree days (measurement of the difference between the average daily outdoor temperature and a specified base-point temperature) when auxiliary heat is required and could reduce the heating season from 8 months to 4 months. In essence, the lower balance-point temperature of a superinsulated house is the overall reason behind why superinsulation design techniques can so dramatically reduce the daily/seasonal heating load and cost for a building.


Now that the principles of superinsulation have been outlined, my next postings will provide several home designs and detailing that incorporate these principles. They will represent a series of solutions, but are by no means the only solutions. Any home can be superinsulated and alternative construction details exist and are possible if the basic principles of superinsualtion are understood and utilized as a total design system.



Many of the principles and concepts presented in my posts are gleaned from "The Superinsulated Home Book" by J.D. Ned Nisson & Gautam Dutt published 1985 by John Wiley & Sons. Most of the principles they presented in 1985 still hold true today and are still in practice. Unfortunately the book is no longer in print, but can be found in some public libraries and on Amazon for a price (I was lucky and got my copy for $35). If you are serious about building a superinsulated house, I would highly recommend investing in this book.

Saturday, January 30, 2010

INSULATION & SUPERINSULATION




Superinsulation is not a material, it is a system consisting of thermal insulation plus other building components which, when designed and installed properly in concert with each other, produce superb thermal performance in a home or business. Proper installation and design are paramount.





HEAT TRANSFER

In case you were sleeping during your science classes, let's begin with the basics. Heat is transferred in three ways --

1. Conduction is the movement of heat energy (from hot to cold) through materials. Different materials conduct heat at different rates. That's why a down filled jacket is warmer than a fleece lining. Hold the end of a knife over a flame and the heat will travel to the other end. Heat inside a house is being conducted through walls, ceilings, windows, doors, etc. to the cold outside.

2. Convection is the transportation of heat energy by a moving fluid - water or air. Natural convection is fluid movement resulting from temperature differences - principle behind radiators transporting heat energy throughout a room by convection currents or heat loss inside an uninsulated wall. Forced convection occurs when an external force acts to move the fluid - forced air furnace or wind drawing heat energy from the house.

3. Radiation is the transfer of electromagnetic energy - e.g. heat transfer from a wood stove to people or materials. Near windows warm body heat is radiated to the cool glass surface making one feel cold. If surfaces are warm, people will feel warm regardless of the air temperature. A room has a mean radiant temeperature (MRT) - the 'averaged' temperature of all exposed surfaces within the room.


INSULATION

Insulation reduces heat transfer through walls, ceilings, windows, doors, etc. by dividing the large interior space of a building component into thousands of tiny air pockets. It is not the isulation material itself that creates the thermal resistance, but the low conductivity of the still air created by these air pockets. All insulation materials - fiberglass, mineral wool, cellulose, straw bales, foams - work by the same principle. Each material is given a conductivity rating (R-value) that measures its thermal resistance to heat transfer. Convection heat transfer is virtually eliminated because the air is trapped and prevented from moving. Radiant heat transfer is greatly reduced because long range infrared radiation is absorbed and/or scattered.


SUPERINSULATION

Insulation

Easy enough, pick an insulation material with the highest R-value per inch! Not so fast. Remember that superinsulation not a material, it is a system. Superinsulation also avoids thermal defects that can reduce the overall thermal resistance of the building components:
  • Insulation Voids: The component spaces must be totally and completey filled. For example, a superinsulated wall or roof installation should have as many voids as roof leaks or plumbing leaks - none. If a wall had 5% overall insulation voids, its overall resistance could be reduced by up to 25%.
  • Thermal Bridges: Thermal bridges are points or components with relatively low thermal resistance that intrude or 'bridge' through the insulation layer of the thermal component - studs, rafters, plates, window & door openings, corner framing, etc. Unlike insulation voids being addressed by thorough and careful installation practices, thermal bridges are addressed through proper design detailing.
  • Air Intrusion: Even if air is not allowed to flow all the way through the insulation system, it can degrade overall thermal performance by merely penetrating the insulation from one side.
  • Convective Loops: Wherever there are hollow spaces around insulation in a wall or ceiling, heat can be transimitted through the system by convection, even if the insulation is completely sealed agains leakage or air intrusion and no inside or outside air penetrates the system. Faced insulation batts stapled to the side of studs leave an air gap between interior finish and he insulation facing. Voids in hollow concrete block walls can develop convection loops cooling the wall. Air chases around a flue can transmit warm air to the attic.
  • Moisture: Moisture comes from human activity - breathing, cooking, bathing, plants, etc. Moisture can degrade the thermal performance of insulation by convection - moisture moving into insulation through gaps - and diffusion - moisture moving through materials. All insulation systems have a dew point - the location within the system where water vapor will condense into water due to temperature.

Air/Vapor Barriers

Air-tightness is a crucial element of the superinsulation system and requires careful attention to detailing and workmanship. Heat loss by poor installation of air/vapor barriers can negate all the beneifits of well installed insulation and can even result in building damage. Air/vapor barriers in a building system will be shown in greater detail when we look at construction detailing in later blogs.

The most typically used air/vapor barrier in buildings today is 6 mil polyethylene sheets. The air/vapor barrier is always located on the warm side of the exterior wall systems where it is will be above the wall's dew point temperature to prevent condensation. Practice over time has shown that an air/vapor barrier can be installed 1/3 of the way into the warm side of the overall insulation and still work effectively. This will come in handy later when electical and plumbing needs to be run in the wall system.

The air/vapor barrier must be meticulously sealed at all seams and at all penetrations including windows, doors, outlets, plumbing, vent stacks, vemt fans, etc. Techniques will be discussed later when we look at constuction details. The air/vapor barrier must be protected throughout the building process and all damages must be repaired as soon as they occur. Before any interior finishes are installed, the entire house should be blower door tested to insure air-tightness of the thermal envelope.


Air Barriers

An air barrier is typially installed on the cold side of the exterior sheathing. This is commonly referred to as 'house wrap' in the building trade, e.g. TYVEK - a spun-bonded polyethylene. Unlike the air/vapor barrier that blocks both wind and vapor penetration, air barriers protects the insulated walls from air intrusion and makes the thermal envelope tighter, but allows water vapor to pass through to the outside. Care should be taken to tightly seal all wall penetrations (windows, doors, vents, etc.) and to tape all overlaps in the air barrier.


Support Structures

These are the structural elements or structural frame of the building - what holds up the building. Support structures must also (1) provide adequate containment of the insulation materials while minimizing the effects of thermal bridging, and (2) provide adequate support of the air/vapor barrier and the air barrier.

For the purpose of my blog, wood frame construction and materials typical of the maritime region will be incorporated. While I will be using double stud wall construction techniques in most details, other walls systems have successfully been used in superinsulated houses, e.g. 2x6 stud wall with rigid insulation as exterior sheathing; TJI joists used as wall studs; strapped walls; larsen trusses; straw bales; etc.

For the purpose of my blog, roof framing will incorporate raised heel trusses and parallel chord trusses to allow for full thickness of insulation material over the entire roof area. More later.


In my next post, I will be discussing heat loss, heat gain, and how superinsulation techniques can dramatically reduce the overall yearly heating requirements of a building.

Many of the principles and concepts presented in my posts are gleaned from "The Superinsulated Home Book" by J.D. Ned Nisson & Gautam Dutt published 1985 by John Wiley & Sons. Most of the principles they presented in 1985 still hold true today and are still in practice. Unfortunately the book is no longer in print, but can be found in some public libraries and on Amazon for a price (I was lucky and got my copy for $35). If you are serious about building a superinsulated house, I would highly recommend investing in this book.