In 2020, I left my desk at Amber Westerman Building Design and started building my own home.This is a 1208 square feet.I designed and shared with over 500 people the super-insulated, all-electric, net-zero demonstration homes of the open house that I hosted during and after construction.Below are the topics I cover in my information on high performance residential buildings.
Slab foundations eliminate the cost and weatherproofing concerns of basements - especially in areas with high water tables.It helps get passive solar energy in the winter and keeps the house cool in the summer.It also supports accessible structures suitable for aging in place.
Plates are placed in two tiers of 2" trays.XPS sheet foam (R-20) has staggered joints.Frost protection is a standard 8 inch thick concrete wall with the base of the frost line.
The vapor barrier directly below the slab serves a dual purpose as an air barrier.It is covered long and over the frosted wall where it is embedded in beads of ChemLink's M-1 low VOC sealant, then folded under the mud base and taped to the wall sheathing to create a continuous air barrier.
The slabs were power troweled and sawn to 10-foot lengths a day later.10 feet.part to control cracking.It was left for six months, cleaned and etched with hydrochloric acid, and then coated with an eco-friendly clear sealant in the spring when surface temperatures reached 60°F.
Beneath the slab is a 6" thick layer of clear stone (no fines) that drains to the outside through a 4" channel.The PVC pipe should be tested for radon in the future.
I chose the double stud wall because it is easy to understand, easy to build, and the material used has a low upfront carbon footprint.
Walls are 11-3⁄4" thick and 24" for outer 2×4 load bearing walls.The center is joined to the 2×4 interior walls by 48” plywood gussets.vertical center.
To avoid toxic materials and enhance the air seal, I used 2×4 western red cedar planks on Conservation Technology’s EPDM gaskets (instead of the traditional 2×4 pressure treated base plate placed on a foam sill seal).
For added wind resistance, I swapped out the usual anchors from Simpson's 3" Titen screw anchors.48" square plate washer.center.After installation, use ChemLink's M-1 Low VOC Sealant to fill the interior base plate to the slab.
The walls are densely filled with cellulose (R-45) after Sureteed's MemBrain (a steam variable membrane) and USG's 1/2-in.EcoSmart Drywall.The steam retarder hangs long, and the drywall is 6 inches shorter at the bottom of each window and at the top of each wall section, which provides plenty of room for the cellulose blower hose.Use ChemLink's DuraSil, a non-toxic, low-odor silicone adhesive, to seal vapor retarders to frames and mechanical penetrations.A vapor retarder (not drywall) is an internal air barrier.
I chose cellulose because there is no other insulating material that consumes less energy to produce, uses more recycled content, is biodegradable, and is less toxic to humans and animals (excluding direct materials such as straw or wood material from Earth).It is a by-product of a paper mill in northern Wisconsin.
Exterior wall sheathing upgraded to 5/8".Tape the plywood and seams with 3M-8067.Nail pattern increased from code minimum to 4 inches.Centered on ends/edges and 6 inches.Center of the field to increase wind resistance.Plywood is the outside air barrier.
The roof is constructed with 24-inch parallel chord trusses.Center — 24 inches.Energy Heel - Across the width of the house.They are fastened to the outer frame wall with Simpson's SDWC truss screws.We built a ventilation slot (the air space used to ventilate the roof assembly) on site by installing 1×2 nails on each face of the top chord to support a 22-1/2" wide 1/2" split.Fiberboard.Old-fashioned wood fiber boards (one side impregnated with asphalt) are cheap and easy to handle overhead.The chutes are open to the eaves and rake soffits which are ventilated through 1×4 slot panels.
As with the exterior walls, Cureteed's MemBrain air barriers and smart steam retarders were installed before the insulation—in this application, a 12-inch wide entry gap was left in the middle of the ceiling.The insulation installer later inserted himself into this gap so he could see the end of the hose as he filled each compartment.Fiberboard above and steam retarder/drywall below form a 22" deep sealed cavity densely packed with cellulose (R-82).Fiberboard is not rated as an airtight material, but it is strong enough to pack densely.It is breathable and protects the insulation from dust and bugs.
Likewise, a vapor retarder (not drywall) is an internal air barrier.It uses ChemLink's DuraSil to seal seams and truss frames.Drywalling the ceiling is a no-brainer - the partitions are installed after.The unit uses 5/8 inch.Thick 12' long boards to minimize the number of seams.The access gap was later covered by 1/2 inch.Thick drywall, so seam feathering is easier.
Roof sheathing has also been upgraded to 5/8".5 ply plywood with spike pattern increased from code minimum to 4".Centered on ends/edges and 6 inches.Center of the field to increase wind resistance.
A 12"3 shed roof isn't the ideal spacing for solar panels at this latitude, but it gave me the sloping ceiling I wanted without a wall that's too high behind.Standing seam galvanized steel roofs work perfectly with solar panels - the rack system simply clips onto the standing seams.None of the PV system components penetrate the roof.Steel can last decades longer than panels.
The roof also has no mechanical penetrations.Ductwork and ventilation ducts/fans leave the walls.Likewise, the ceiling is not penetrated.Instead of a ceiling or can light, I opted for a pendant that hangs from a wall socket.This is a personal aesthetic preference, but it does eliminate potential air leakage and insulation displacement.No need to worry about wiring, insulating the ceiling and drywall prior to installing partitions is not a problem.
Together, these systems form some of the fundamental building blocks, and high-performance homes are being built more and more regularly - because they work.My home is very energy efficient, thermally comfortable, healthy to live in, and many other attributes.
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Post time: Apr-27-2022