Last time we spoke about the benefits of building a tight home and some consideration for that home. This time, let’s look at ways we make homes good and tight. These are common things that often get overlooked and forgotten in the process of building a home. It is now fairly standard to have the Super Seal package. That is caulking all seams and joints in the stud prior to the walls being closed. Areas that are often overlooked are multiple stacked studs, kings, jacks and cripples. These seams should be caulked as well. If there is a wooden lolly column instead of a steal column, each seam should be sealed.
Walls and outlets.
Receptacles in exterior walls are a big weak point. Receptacles for the interior and exterior in these walls should be sealed and insulated well. Sometimes we just stuff fiberglass behind them. This is no good. It does not seal leaks and the insulation usually is compressed greatly. Best is to foam in the back side and/or cut the insulation to fit nicely. I have seen one builder get styrofoam boxes made for this purpose. They attach to the stud over the box. The penetrations for the wires get caulked or foamed in. The face of the box is flush with the stud to help with sealing the entire unit to the drywall.
In advanced sealing we often recommend gluing the top plate of the wall to the drywall that is adjacent to the attic. One builder I know uses simple weather stripping to seal this joint, this real well. However, you often cannot rely on the drywaller to glue this. This is unusual for many.
Here they sealed the edges but forgot to seal the box itself.
The wall for the garage here was sealed well above the ceiling. This is often forgotten.
The standard foam sill seal is often not enough. A bead of canned Great Stuff foam can do the job just right. This goes well for all the utility penetrations in the foundation.
The sill and band joist are critical. Here they forgot to see the 1/4′ gap for 2′ along the band joist.
Another energy efficient item, Lighting.
The IECC requires 50% energy efficient lighting. Advanced programs require 80%. It is not a huge cost to add more energy efficient lights. One of the lapses I see in lighting is in recessed units. Often they are incandescent for dimming purposes. The standard CFL bulbs don’t like to dim. The better alternative is LED bulbs. If the customer wants an abundance of recessed lights I would tend to direct them in the direction of LED lights. Standard incandescent lights consume huge amounts of energy and produce a lot of heat that has been known to challenge the homes heating/cooling syst ems.
I won’t speak about efficient HVAC Systems, since we all know that fairly well. However if they are not installed well, that efficiency literally goes right out the roof. I’m speaking about duct work. Often duct returns are in cavities that are unsealed. This allows the conditioned air to transfer and draw in air from the outside. This is very old school, the better way to do this is to hard pipe the returns. In the next revisions of the IECC this will be a requirement. Let just do the right thing now. The issue is the returns and the top plate leak significantly because they are usually poorly sealed and not insulated well. The cavities themselves breathe through the receptacles that the electrician put in the cavity as well. A compromise to this is completely seal the cavity with thermopan. Then seal edges and seams with caulk and or mastic. The duct tape does not sick to the wood stud. I have seen it peel off the wood studs in a matter of weeks.
Here is an switch that is sealed that is in a return. But in the same house there are floor cavities used as returns, not recommended.
The thermopan is vertical in the bay, but when the ceiling is placed there will be gap at the bottom that will never be sealed. This leaks not just to the interior, but this cavity as we saw before can be directly connected to the outdoors at the band.
Windows are expensive and are important. But if they are not installed well, they can be an issue. Usually I have seen that window units themselves are not the issue, but poor installation is at fault. In the 2009 IECC check list it states that you cannot use any insulating product as an air sealing method. In simple terms what this means is you can’t use fiberglass to seal the frames of window. It never works. The only way to do it properly is to use the correct foam or caulk. I have seen all too often it is the space around the window that leaks, not the window!