Your roof deck needs 3 inches of Closed-Cell Spray Foam Insulation, and this is why; when it comes to your roof deck. If your dew point isn’t targeted through sufficient insulation materials, condensation can form. This will lead to moisture buildup, and eventually mildew, rot, and other cosmetic issues that will inevitably compound if not identified and eliminated immediately. Costing you thousands of dollars in property damage.
If you live in the Pacific Northwest, we always recommend spraying 3 inches of Polyurethane Closed-Cell Spray Foam Insulation into your roof deck. By spraying 3 inches, you can effectively target your dew point, and eliminate the risk of condensation.
Some clients & customers have asked why we recommend 3 inches instead of 2 inches when spraying a roof deck. The answer is that it’s heavily contingent upon your weather environment. Because we service the Pacific Northwest, we advocate for 3 inches over 2 inches. This is because of the climate conditions in the state of Oregon. 3 inches of Polyurethane Closed-Cell Spray Foam Insulation targets the dew point, whereas 2 inches does not. Ultimately, it’s an industry best practice to determine your environmental conditions before utilizing Closed-Cell SPF Insulation in your building envelope. As you first need to identify the dew point of your building envelope and roof deck for the Spray Foam Insulation to yield effective results.
Eliminate condensation with Spray Foam Insulation on your Roof Deck
Due to the temperamental, environmental conditions of the Pacific Northwest (Oregon & Washington), attics & crawl spaces are prone to dew points forming if not properly insulated. Which causes condensation to occur (especially among insulated attics and crawl spaces that utilize fiberglass or cellulose as opposed to Closed-Cell SPF Insulation). By spraying 3 inches of Polyurethane Closed-Cell Spray Foam Insulation, you will effectively target the dew point, eliminating the potential for condensation to form. Thus eliminating any potential mold or mildew damage to your home, commercial building, or agricultural facility.
Call today to learn more about the best practices we implement when utilizing and applying spray foam insulation. Go Green. Go Foam.
Common Questions
Why 3 inches on a roof deck and not 2?
Two inches gives a 94% reduction in heat flow and three gives 96%, so the extra inch is not about the thermal number. It is about where the dew point sits. Three inches moves it into the foam instead of onto the underside of the sheathing, which is where condensation and rot start in this climate.
Does this apply outside the Pacific Northwest?
No. The specification follows the climate. A long damp heating season and a big solar swing on the roof is what pushes the requirement to three inches here. In a drier or milder climate the right answer can be different, which is why we assess the assembly rather than quoting a standard number everywhere.
What happens if a roof deck was sprayed at 2 inches?
It may perform acceptably, or it may condense on the sheathing through winter. The failure is slow and hidden: mildew, then rot, then structural repair. Putting it right means adding depth where access allows, which costs more than doing it once correctly.
Related: how thick closed-cell foam needs to be · spray foam roofing in Oregon
Also worth reading: what a thin install costs to fix, examples of bad spray foam work.
Talk it through with an installer
Every building is different. Tell us about the property and we will give you a straight answer on what it needs.