Rigid insulation is one of the reasons why flat roofs are synonymous with high energy efficiency. Compared to cavity insulation systems, where blankets of fiberglass batts are pressed between ceiling joists, sheets of rigid insulation have no gaps in them. In turn, they provide continuous and consistent coverage to prevent dramatic temperature fluctuations in living spaces and premature sheathing failure.
However, enhanced home energy efficiency isn’t a guarantee with a flat roof. If you get bad advice, you might misuse attic insulation, which could produce meager financial rewards, no greater comfort and even hazards.
If you ask a credentialed residential and commercial roofing specialist like Elite Roofing Solutions, they would tell you that these are the four insulation mistakes to avoid:
Some roofers suggest installing two inches of closed cell foam under four inches of rigid foam, and then add R-30 fiberglass batts. In theory, this combination of insulation materials can produce a total R-value of nearly 62. In reality, though, this can be impractical because of the cost to apply all of them. The better alternative to achieve the same or even more R-value is by using thicker rigid insulation.
You may be on a budget, so buying fiberboard as an alternative to a traditional insulating material isn’t cost-effective. Any residential roofing expert would tell you that its insulating value per inch is only R-1. Considering how bad it is as an insulator, it’s likely to allow attic condensation. In turn, there’s a risk of it getting wet and becoming even less effective.
Fiberboard is most useful as a glue-down surface on a roof covering a non-living space. Even if your attic is seldom utilized, don’t install it here in order to avoid excessive heat transfer from it to the finished rooms below and vice versa.
Laying Over Vents
Good attic insulation without proper ventilation is still a recipe for disaster. Any roof, cool or not, would transfer solar heat into the space below. Without ample air circulation, the temperature in the attic would inevitably rise, baking the roofing materials above. While it’s imperative that no gaps are left, blocking exhaust vents would choke the attic.
Installing Over Recessed Lights
Unless your recessed lights in the ceiling are Insulation Contact-rated or use pre-manufactured covers, be careful not to install insulation on top of them. They generate a lot of heat, making them a fire hazard. Make sure there’s at least three-inch clearance between recessed lights and any insulating material.
Set up an appointment with Elite Roofing Solutions to ensure your flat roof has adequate and properly installed insulation. Call us at (855) 588-6610 now to get a FREE estimate in Houston, TX, or any area nearby.