After you address air leaks in your home by air sealing, then ⊠and only then ⊠you can add insulation.
- Start here to read the beginning of the âReady your envelopeâ series.
Why it matters: Adding insulation without air sealing is like putting on a sweater over bare skin and walking outside when itâs 20 degrees and windy.
- As great as that sounds when itâs 100 outside, if youâve done that in the winter you know that air moves through insulation.
âïžÂ How it works: Loose fill and batt insulation is a THERMAL barrier only â> which resists the transfer of heat.
- Itâs not an air barrier or a moisture barrier.
- Wind blowing through soffit vents in the attic or pressure differences between your attic and house can draw air and vapor through the insulation.
đ What about spray foam?
- Spray foam comes in two main varieties â> open cell and closed cell.
- Open cell is most commonly used for spraying the underside of the roof deck â> closed cell used the same way is even better, which is why itâs much more expensive.
- Closed cell is what you buy in the individual cans and should be used to cover seams and crack before open cell is sprayed.
- Closed cell is also great for air sealing penetrations in walls and ceilings.
đ„ Reality check: Done correctly, spray foam can be very effective.
- But, but, but ⊠depending on your attic shape, it can be very difficult to do it well â> which is why itâs more effective in new construction.
- And spray foam carries a few other risks like creating potential moisture issues at the ridge line of the attic and making it difficult to diagnose a roof leak.
â Â For your Smart Homeowner list
- Before you invest in more insulation, make sure your attic is properly sealed.
- Which can be tested and verified using the right equipment.
- If you need help navigating your next step, letâs chat.
Best,
Travis