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Justina Harvey
5 years ago
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2 Lisa Alexander, LEED AP Certified Eco-Broker Green Building & Sustainable Living Consultant

The Building Envelope A building envelope includes all the components that make up the shell or skin of the building. These components separate the exterior of the building from the interior.

3 The Building Envelope A building envelope includes all the components that make up the shell or skin of the building. These components separate the exterior of the building from the interior. The building envelope may also be defined as the components that separate conditioned areas from unconditioned space. Exterior or unheated living spaces are not included inside the envelope, while any living space that is equipped with heat or air conditioning would be included. TEXT

4 Building envelope design includes four major performance objectives: Structural integrity Moisture control Temperature control Control of air pressure boundaries of sorts

5 Foundations CMU - Concrete Masonry Units or Block, the worst! Water and air infiltration nightmares! Poured in Place/on-site Concrete Walls- Strong, less permeable than CMU s but a big waste of wood framing, still needs insulation, can crack and allow water flow.

6 Pre-Cast Concrete Walls, poured in a factory and delivered to site, installed by cranes. Goes up much faster than poured on site walls. An uninsulated basement can account for over 33% of the total heat loss in your home. Insulated precast concrete wall panels provides your home with an excellent thermal envelope, minimizing the potential for energy leakage. Poured into molds in a factory under controlled conditions and designed specially for each job, drastically reduces waste. Features a continuous layer of insulation bonded directly to the concrete, at the factory, resulting in high energy efficiency to help reduce energy costs.

7 ICF s - Insulated Concrete Forms ICF s are light-weight hollow blocks made from Expanded Polystyrene (EPS), which was developed as a use for a waste-stream product in the development of oil. In other words, it was originally considered post-industrial recycled material. The styrene resins are transported to the local molding plant, where they are expanded to 28 times their size with the use of only air and moisture. On site ICF s are stay-in-place formwork that are stacked like LEGO s, reinforced with Rebar and then the cores are filled with concrete to provide a structural wall system with ready-made insulation on both sides of the wall giving an average R-value of 25, but can be much higher depending of the thickness of the pour. Can be used for basement or the whole building, giving natural sound-proofing along with superior insulation.

9 The Pros of ICF Walls Faster to build..goes up like Lego s Higher Energy-Efficiency & Thermal Comfort - because they are filled w/ concrete, the walls won t have gaps as in wood or steel framed walls, making monthly heating bills up to 50% less. Higher Thermal Mass (ability to store temperature) & Higher Insulation (ability to hold temperature), this combination helps regulate daily temperature swings, keeping building consistently comfortable. Reduces Noise, ICF s Mass & Insulation deaden outside noises. Fill the cores w/ concrete made from Fly Ash or Slag and reduce your carbon footprint even more and get more LEED points!

10 Cons of ICF S You ll have to carefully pre-plan for you electrical chases and plumbing before hand as to reduce cutting into the ICF and Concrete later as this will reduce your insulation values. Must also plan for all openings, windows doors etc...to avoid cutting into the finished walls later. Costs...usually about 5% more upfront costs than traditionally framed home, but you can make that up in reduced energy costs over the life of the building.

11 WALLS Traditional Wood Framing - 16 on-center Advance Framing Techniques - 24 on-center Steel Framing Timber Framing or Post & Beam Structural Insulated Panel - SIP Masonry - CMU S, ICF S, Poured in place concrete Natural Building Methods Straw Bale Construction, Rammed Earth, Adobe, Cob, Cord Wood, etc...

12 Traditional Wood Framing/ 16 on-center % of Homes in USA are built using Traditional Wood Framing or Platform Framing. 16 on-center - wood studs are measured from the center line of one stud to the center line of the next stud. Walls are constructed w/ wood studs of 2x4 s or 2x6 s on wood deck built on top of a foundation. Each floor or platform is built on top of the other. The roof is framed w/ solid wood rafters commonly called roof trusses. the outside is covered with sheathing of either plywood, OSB ( oriented strand board, particle board, or wheat board - look for these made from FSC Certified Wood, and formaldehyde- free, green guard certified)

13 Advanced Framing Techniques Uses 24 on-center allowing to reduce thermal bridging ( heat flows more quickly through wood than insulation) by allowing more space for insulation. Done properly it is just as strong as 16 on-center. Floors & roofs are built 24 on center so by being able to line up the studs, requires less wood needed to build a double support plate on top of 16 on center studs. Advance framing techniques only require a single top plate. Corners are built out of just two studs Double or cripple studs at windows are eliminated All used together, advanced framing techniques allow for more wall area to be comprised of insulation rather than wood, so the average insulating value of the wall is higher, you ve save money on wood and time in construction.

15 Environmental Impact of Wood Wood is not a good insulator and causes Thermal bridging heat lows through wood more quickly than insulation. An average size home of 2,000 sq. ft uses an acre of wood in framing alone, that s about 44 trees. 4,000 sq ft uses 2 acres & 88 trees and so on... Unless it has the FSC logo ( Forest Stewardship Council Certification that the wood was harvested from sustainably managed forests) these trees are clear-cut which leaves nothing for future generations. Lumber industry at 11 Billion $ s a year is big business that pollutes our water ways and air. The Lumber Industry is the 2nd Largest source of green-house gases and global warming pollution, after coal production.

16 Steel Framing Rot, Insect, Fire, Mold resistant, but conducts heat and cold more easily than wood, thus decreasing R-values. Can be used for exterior walls, but best left for interior walls. Saves trees as most steel is made from recycled content. Strong, Durable & light-weight, and consistent in size & quality. Great for all walls in milder climates.

17 Timber Framing Often referred to as Post-and-Beam Construction Key advantage is durability, most timber framed homes built by the colonist are still standing 300 years later. Often uses locally milled or re-salvaged timbers Today they are often used with Structural Insulated panels for higher R-Values and ease of construction.

Structural Insulated Panels Structural insulated panels (SIPs) are high performance building panels used in floors, walls, and roofs for residential and

The panels are typically made by sandwiching a core of rigid foam plastic insulation between two structural skins of oriented strand board (OSB).

18 Structural Insulated Panels Structural insulated panels (SIPs) are high performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are typically made by sandwiching a core of rigid foam plastic insulation between two structural skins of oriented strand board (OSB). Other skin material can be used for specific purposes. SIPs are manufactured under factory controlled conditions and can be custom designed for each home. The result is a building system that is extremely strong, energy efficient and cost effective. Building with SIPs will save you time, money and labor.

19 Insulation Checking your home s insulation is one of the most effective ways to use a whole-house approach to reduce energy waste and make the most of your energy dollars. A good insulating system includes a combination of products and construction techniques that protect a home from outside hot or cold temperatures, protect it against air leaks, and control moisture. You can increase the comfort of your home while reducing your heating and cooling needs by investing in proper insulation and sealing air leaks. Starting with an energy audit is the best, but can cost a few hundred dollars. An easy way to determine air leakage and flow is to light an incense stick and walk around the house putting it near windows and other openings such as outlets and see where the air is flowing.

20 Five Main Areas of Heat Loss Air Movement Walls Windows Foundation Attic Carefully check the insulation in your ceilings, exterior and basement walls, floors, and crawl spaces, windows to see if it meets the levels recommended for your area. Insulation is measured in R-values the higher the R-value, the better your walls and roof will resist the transfer of heat. DOE recommends ranges of R-values based on local heating and cooling costs and climate conditions in different areas of the nation.

21 Quick Terms R-Value - measure of a material s resistance to thermal conduction. The higher the R-value the higher the insulation value. U-Factor - measure of thermal conductance of a material. Expresses how much heat ( in BTU s) is transmitted through one square foot of material in one hour when temperature difference on opposite surfaces is 1 F. A higher U-Factor indicates higher conductivity to heat and lower R-value. Windows are measured in U-factor.

22 Climate Zone 6 Ceiling R-value 49 Wood Frame Wall R-value 20 or 13+5 h Mass Wall R-value 15/19 Floor R-value 30 Basement Wall R-value 15/19 Slab R-value d, Depth 10, 4 ft Crawlspace Wall R-value 10/13 Fenestration U-Factor 0.35

23 Where to Insulate & Where the Leaks Are

24 Insulation Types Cellulose Available as loose fill. Appropriate for small to large remodels in parts of the structure with very low to no moisture. Good for wall cavities or attic floors and ceilings. Wall cavities need small holes to spray through. Can be blown in dry, or sprayed in damp to prevent gaps and settling. * Requires up to 30 times less energy to make than fiberglass and mineral wool * At least 75% post-consumer recycled content (newspaper) * No effect on indoor air quality (treated with nontoxic borate) * Can absorb moisture * Can settle (if blown in dry) Cotton Available as batt and loose fill. Appropriate for small to large remodels in areas with very low to no moisture. Good for wall cavities or attic floors and ceilings. Batts require open walls. * Renewable, plant-based material * At least 70% post-industrial recycled content (e.g., denim) * Recyclable * No effect on indoor air quality (treated with nontoxic boron) * Cotton farming typically uses large volumes of water and pesticides

25 Fiberglass Available as board, batt, and loose fill. Appropriate for small to large remodels in areas with very low to no moisture. Good for wall cavities or attic floors and ceilings. Batts and boards require open walls. Boards can be used in interior basement spaces. * Made of abundant material (silica) * Up to 40% recycled content * Releases eye, throat and skin irritants * Energy-intensive manufacturing process * Some products contain formaldehyde Polyisocyanurate Foam Insulation Foam insulation boards. Appropriate for larger projects or new construction in areas with low to no moisture. Choose closed-cell option for higher moisture areas. Best for interior basement walls, beneath siding, and attic ceilings. * No hydrochlorofluorocarbons (HCFCs) * Typically no indoor air quality effects * Made from petrochemicals * Not recyclable

26 Polystyrene Expanded (EPS) Foam Insulation Foam insulation boards. Appropriate for larger projects or new construction in areas with low to no moisture. Best for interior basement walls, beneath siding, and attic ceilings; can be used below grade if coated with foil or plastic. * No HCFCs * Recyclable * Typically no indoor air quality effects * Made from petrochemicals * Contains highly toxic HBCD brominated flame retardant and other toxins Polystyrene Extruded (XPS) Foam Insulation Foam insulation boards. Appropriate for larger projects or new construction in areas with moderate to no moisture. Best for interior basement walls, beneath siding, attic ceilings or below grade. * More moisture resistant than EPS * Typically no indoor air quality effects * Recyclable * Most products still use HCFCs (but they are to be phased out by 2010) * Made from petrochemicals * Contains highly toxic HBCD brominated flame retardant and other toxins

27 Spray Polyurethane Foam (SPF) Insulation Spray foam is appropriate for small to large remodels in areas with moderate moisture. Good for wall cavities and attics. Sprayed through small holes in walls. * No HCFCs * Prevents air leakage * Doesn t settle * Low density SPF bio-based products are available, which use up to 33% soy oil * Not recyclable * Most SPF products are made primarily from petrochemicals Mineral Wool (AKA Rock Wool or Slag Wool) Available as batt, loose fill, and board. Appropriate for small to large remodels in areas with moderate to no moisture. Good for wall cavities and attics. Batts and boards require open walls. Can be used below grade if made for that purpose. * No additional flame retardants necessary * Abundant materials (steel slag or natural rock) * Moisture resistant * Often contains 75% 90% recycled content

28 Sealing Air Leaks Warm air leaking into your home during the summer and out of your home during the winter can waste a lot of your energy dollars. One of the quickest dollar-saving tasks you can do is caulk, seal, and weatherstrip all seams, cracks, and openings to the outside. You can save on your heating and cooling bill by reducing the air leaks in your home. First, test your home for air tightness. On a windy day, carefully hold a lit incense stick or a smoke pen next to your windows, doors, electrical boxes, plumbing fixtures, electrical outlets, ceiling fixtures, attic hatches, and other locations where there is a possible air path to the outside. If the smoke stream travels horizontally, you have located an air leak that may need caulking, sealing, or weatherstripping.

29 How Does the Air Escape? Air infiltrates into and out of your home through every hole and crack. About onethird of this air infiltrates through openings in your ceilings, walls, and floors. Fans and Vents leak 4% Electrical outlets - 2% Windows - 10% Floors, Walls, Ceilings 31% Doors - 11% Plumbing & Penetrations - 13% Fireplace - 14 % Ducts - 15%

30 Fix Those Leaks! Caulk and weatherstrip doors and windows that leak air. Caulk and seal air leaks where plumbing, ducting, or electrical wiring penetrates through walls, floors, ceilings, and soffits over cabinets. Install foam gaskets behind outlet and switch plates on walls. Look for dirty spots in your insulation, which often indicate holes where air leaks into and out of your house. You can seal the holes with low-expansion spray foam made for this purpose. Look for dirty spots on your ceiling paint and carpet, which may indicate air leaks at interior wall/ceiling joints and wall/floor joists. These joints can be caulked. Install storm windows over single-pane windows or replace them with more efficient windows, such as double- pane. See Windows on page 18 for more information.

31 When the fireplace is not in use, keep the flue damper tightly closed. A chimney is designed specifically for smoke to escape, so until you close it, warm air escapes 24 hours a day! For new construction, reduce exterior wall leaks by installing house wrap, taping the joints of exterior sheathing, and comprehensively caulking and sealing the exterior walls. Use foam sealant around larger gaps around windows, baseboards, and other places where warm air may be leaking out. Kitchen exhaust fan covers can keep air from leaking in when the exhaust fan is not in use. The covers typically attach via magnets for ease of replacement. Replacing existing door bottoms and thresholds with ones that have pliable sealing gaskets is a great way to eliminate conditioned air leaking out from underneath the doors.

32 Build Tight... Ventilate Right... Once you have sealed your home make sure you still have proper air flow or air exchanges. This is best done with mechanical ventilation. The optimal rate of natural air exchanges in a home that is a good compromise between indoor air quality and energy efficiency is 0.35 Air Changes per Hour ( ACH ).

About Insulation & R Value - cmhc.ca

About Insulation & R Value - cmhc.ca Insulating Your House While previous generations may have been content to live in drafty houses, most people now want comfortable warm houses. A healthy house today