Mapping Your Home to Optimize Air Sealing

[@WillLeingang]

This is super helpful. Watching pros do it makes me feel a lot more comfortable doing it myself!

[@UxAxDeltaT]

DAN! So proud to have come up in the trade with this guy, we miss you in the northwest. Air sealing details are something we train hard with our crews on, it is critical for energy efficiency, healthy IAQ, comfort, and building durability. We get one chance to do it right ahead of insulating, make sure you hire a pro who will sweat these details!!

[@ComfortReadyHome]

Totally agree! Understanding the systematic workings of the building and creating a thoughtful plan with good craftsmanship is the key to success. Keep up the good work.

[@TNNLZ]

Great vid - Would’ve liked to see a little more info on the fireplace perimeter seal, I’m working on this myself. I was hesitant to hire for this job so I’m doing it myself, but I would trust this crew to do a good / thorough job 👍

[@ComfortReadyHome]

Thanks! If you are in the Pacific Northwest, there are many fantastic contractors that all take similar trainings on our contract finder: comfortreadyhome.com/contractor-search. And whether you continue on your own or end up with a contractor, this resource can help with a little more specific information: comfortreadyhome.com/wp-content/uploads/2023/11/CRH-Single-Family-Prescriptive-Air-Sealing-At-A-Glance.pdf

[@leighchristie140]

my house has a nearly identical attic. I live in Vancouver. We recently removed all the vermiculite and cellulose. and sprayed biocide to kill the milldew mould. and then sprayed a preventative clear layer to prevent future mould. we increased the ventilation in the soffits and roof. and we air sealed everything. now we are putting in rockwool insulation everywhere. Not sure yet what to do about the vapour barrier. If anyone wants to compare notes, reach out!

[@functionalvanconversion4284]

Great information! I recommend completely extracting all insulation, so you can see all the penetrations, its amazing how much you can miss with insulation in the way.

[@ComfortReadyHome]

Thanks for the recommendation. It is certainly great to remove existing insulation to make the air sealing job easier and ensure thoroughness. When it is not feasible to remove insulation or if the existing insulation is in good condition, mapping out the where the walls, architectural details and lights are from the living space can give a very complete and precise mapping of where penetrations are likely to be.

[@functionalvanconversion4284]

@@ComfortReadyHome I agree; however, when it comes to icedamming certain situations will require more than just air sealing. Moving ducts, vents, and using better insulation materials. I tried doing it without full extraction on two buildings for 11 years and finally exhausted myself of paying roofers to shovel snow off the roof only to discover damage in the spring from aggressive snow shoveling. You are right though, if you can avoid the cost, and fix it, then go the simple route:)

[@WakandaBabe]

I had the old insulation in my attic removed entirely, my home rewired and then the attic and basement were air sealed. The insulation work was meticulously done by BPI contractors. Then new cellulose insulation was blown in.

[@ComfortReadyHome]

That’s the way to do it!

[@rickmartinez96]

Will air sealing stop rising humidity in a home ?

[@markr857]

Yes. About 99% of the moisture movement into the attic is through air leaks flanking the building materials, and the remaining 1% is by diffusion through the materials themselves.

[@CantankerousDave]

Wish you’d shown how you dealt with sealing the mount for the big rectangular light box in the kitchen.

[@ComfortReadyHome]

The mount is held up by fasteners to the joists. These fasteners don’t typically pose a compromise to air leakage. The air sealing opportunity was where the wiring comes through. The wiring typically runs through a drilled hole that feeds to an electrical junction box fastened to the joist. The team was able to access the wiring as it came through the ceiling and install some spray foam at the penetration. This application looks very similar to the video cover image: i9.ytimg.com/vi/peGZpxePEs4/sddefault.jpg?v=65288c40&sqp=CPCLvqsG&rs=AOn4CLD7IOs4Bv4WBjE7vyQSmh-1Pi4H2w

[@bluestsky1999]

Is it a good idea to build a warm roof above all the studs and frame? I plan to redo my attic floor(or roof)

[@ComfortReadyHome]

If you are planning on using that space in other ways, moving the building envelope can have its benefits. However, when changing from the original architecture design, it is important to understand its effects on other systems. Adding a new space to the home will change its heating and cooling requirements from the HVAC system, moisture and ventilation will need to be considered, and always check with your local code jurisdiction on required R-Value and space usage. A home’s independent spaces and parts work as a system, when one is changed it is more than likely others will need to be too.

[@Xris18713]

Silicon on can lights? I wouldn’t want to replace those in the long run

[@marydolan2733]

Was a blower door used? What were the numbers?

[@ComfortReadyHome]

The contractor did use a blower door for pre and post-testing, but we don’t have those numbers for this particular project.

[@eddieadams4770]

What possible difference does it make whether the attic cracks are sealed off from the ceiling of your house? The attic floor is covered with R60. The only difference between the unsealed area of your ceiling letting air escape into that R60 blanket and the rest of your ceiling is some air hits the seal or drywall first. So, if it's an unsealed location, the escaping hot air from your ceiling runs into R60. If it's a sealed or 1/2-inch drywall area, the escaping hot air first runs into the seal or the drywall, so essentially R61. No practical difference.

[@ComfortReadyHome]

Thanks for your question! It sounds like you are asking if air sealing is necessary with high insulation levels in an attic. There is an important distinction between the effects of rated R-value vs. proper air sealing. R-value is the resistance to conduction of heat through a material where heat warms the surface and slowly (or quickly) moves through the material by heating the material. Air sealing is important in all cases to optimize the full potential of the insulation because air will move directly through it reducing the effectiveness of the labeled R-Value. In more technical terms, the R-value equation does not take into consideration air movement, only the heat flux (heat flow density) of the material and the temperature differential. In practice, the R-value can’t be obtained without proper air sealing. If you're interested, our video “The Power of Retrofit” details the effect of proper air sealing and insulation in a home and their individual effects on HVAC system sizing: kzbin.info/www/bejne/m4qbq4WkltGYfM0

[@miketyrawa1568]

Were you guys able to seal the top plates around the perimeter of the house (outside walls). If so, how did you do it? Also, do you need to spray foam each rafter that makes contact with the drywall ceiling?

[@ComfortReadyHome]

Thank you for your question! In most homes, the top plate should be accessible on the outer walls. The part that should be air sealed is where the drywall or lathe and plaster meet the top plate and where perpendicular walls are connected. Electrical lines sometimes go through here to porch lights and switches. Depending on the slop of the roof, this can be a very tight situation. If the home is balloon framed, proper blocking will need to be considered before air sealing can be done effectively. Don’t forget to put baffles for the lower attic ventilation. It is important to determine what is exactly considered inside the home and what is outside the thermal envelope. In most homes, the rafters of an attic do not penetrate the thermal envelope and do not require air sealing at the junction and rest on the outer wall or attic pony wall. A blower door test can be an effective way to see and feel how the house is interacting with air through the assembly.