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.

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.

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.

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.

SUPERINSULATION - AN INTENTIONAL CHOICE

Why would I propose the use of superinsulation building techniques is the design of a new home or business? The rationale comes down to intentional living. We are faced with choices throughout our lives, but all too often we do not make conscious decisions. We rely too heavily on the status quo. We find comfort in following the mainstream. My wife and I have made the decision to develop a lifestyle based upon our own intentional choices. The concepts of superinsulation would be one of those choices.

We live in a cold climate, on the Northumberland Strait of New Brunswick, Canada. To live in this climate we need to make choices to include staying comfortable during the long winter months with a minimal impact on the environment. When I lived in Missouri, my winter coat included a waterproof wind breaker with a removable fleece lining. Now that I live in New Brunswick I needed to upgrade to a longer, down filled winter coat with an internal wind break. My new NB winter coat cost me a bit more than my old Missouri coat, but the benefits I receive are well worth the added cost.

Choosing superinsulated design for a home is a similar choice. We build homes on what are common building practices. Homes built today are better insulated than homes built prior to 1970. However, we still rely too heavily on heating systems to provide our comfort. Superinsulated design begins from the premise that if we built higher efficency into our homes, we would spend much less to heat (and cool) our homes over time. The additional 5-10% in construction cost would be more than offset over the life of the building not to mention the additional comfort provided. What are some of the benefits:

• Reduced Heat Loss = Lower Fuel Bills: The heat loss in a superinsulated house is 60-80% lower than that of a pre-1970 conventional house, with a 80-90% reduction in annual fuel cost.

• Few Architectural Constraints: Almost any housing type or style can be built using superinsulation principles. However, some are better suited than others.

• Microclimate Is Not Significant: While wind protection and solar orientation are desirable, they are not critical factors in the building design and operation.

• Macroclimate Is Less Important: The superinsulation principles are applicable to most cilmates with the exception of severe extremes.

• No Need To Retool: A superinsulated house can be designed using local materials, trades, and building techniques, but with refinements. The one new and important constraint placed upon the the building industry - a stricter attention to quality.

• Do Not Require Sacrifices: Sperinsulated homes can have better air quality, can have plenty of natural light, provide even temperatures throughout, eliminate drafts, eliminate cold surfaces, control humidity, and are quiet.

In future posts, I will discuss how a superinsulated home works and provide some examples of homes based upon traditional housing types found in the maritimes.

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 used 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.