Vapour barriers are an important part of a building envelope. They are particularly useful in an attic, where they play a vital role in maintaining a home’s structural integrity and energy efficiency.
Why a Vapour Barrier is Important
This lining between the topside of your ceiling drywall and the insulation prevents condensation buildup within the structure.
That serves two important purposes:
- Prevents Condensation: A vapour barrier stops moisture from condensing within the structure, which can lead to mould, mildew, and rot. This is particularly important in attics, where temperature differentials can cause significant condensation issues.
- Enhances Air Sealing: Due to the stack effect, where heat rises through the home, adding a vapour barrier is an excellent opportunity to air seal the home. This prevents warm, moist air from escaping into the attic and condensing on cooler surfaces.
The Process of Adding a Vapour Barrier
When insulation already exists in an attic, the process of adding a vapour barrier looks something like this:
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Removal of Existing Insulation
The first step is to remove the existing insulation. This is necessary to create a clean surface to apply the vapour barrier.
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Application of Spray Foam
We then apply spray foam insulation to the topside of the ceiling drywall. Spray foam insulation is a dual-purpose product that acts as both an insulation material and a vapour barrier.
- High R-Value: Spray foam offers the highest R-value per inch among insulation products, providing superior thermal resistance.
- Expands to Fill Gaps: It expands to fill nooks, crannies, and penetrations in the ceiling, effectively sealing the attic and preventing heat from escaping.
- Mould and Mildew Resistant: Spray foam can resist mould and mildew, and it doesn’t absorb water.
- Quick Curing Time: Spray foam cures in just 30 seconds upon application. It emits fumes for only 24 hours, after which it becomes a permanent part of the structure, similar to a piece of furniture.
- Radon Blocking: Spray foam’s added benefit is its ability to block radon, a naturally occurring radioactive gas that is Canada’s second leading cause of lung cancer.
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Extra Insulation Options
After applying the spray foam for a vapour barrier, you can choose from two more options for insulating your attic:
- More Layers of Spray Foam: Extra layers of spray foam can be applied for maximum insulation.
- Top-Up with Fibreglass Insulation: For a more cost-effective solution, blown-in fiberglass insulation can be added over the spray foam. This hybrid material combines the benefits of both ford ultimate insulation and air sealing.
We want you to be confident in your well-insulated, air-sealed attic that contributes to a healthier, more comfortable home! Call us today to talk about our insulation options to give you this confidence.
