The trapped gases in the cells of polyiso and XPS foam assist to provide an initial high R-value. During the life of these foams, air from the atmosphere diffuses in and the trapped gases diffuse out. The result is polyiso and XPS lose R-value over their lifetime.
What is the R-value of rigid foam board?
Extruded polystyrene: Extruded polystyrene (XPS) rigid foam is usually blue or pink in color, with a smooth plastic surface. XPS panels typically aren’t faced with other material. The R-value is about R-5.
What cover board material offers the highest R-value?
The high R-value and light weight of high-density (HD) polyiso cover boards provide important contributions to the design of a durable roof system. A typical 0.5” thick HD polyiso cover board adds R-2.5 to the total R-value of the roof insulation system.
How thick is polyiso R25?
Develop a 2-inch thick composite foam insulation board with R25 (hr-ft2-F/Btu), with a cost premium of $0.30/ft2.
How thick is R30 rigid insulation?
Typical R-30 fiberglass insulation is 10-inches-thick. Prior to buying fiberglass insulation, it is important to measure the joint spacing you are working with. Note that the actual space between the framing members will be less than 16 or 24 inches, but the foam batts can easily be stuffed between these lengths.
How long does polyiso insulation last?
Polyiso foam board insulation provides long term thermal resistance values over a period of 15 years.
Does polyiso degrade over time?
Polyisocyanurate (polyiso), XPS, and spray closed-cell foams substantially degrade over time as the insulating blowing agent gases diffuse out and plain air diffuses in.
Does polyiso work in the cold?
When tested at mean temperatures below 50°F, polyiso performs worse than it does at a mean temperature of 75°F. The reason for this declining performance, according to Schumacher, is that “the trapped blowing-agent gases start to condense at cold temperatures.”
What is the thinnest insulation with the highest R-value?
Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers.
What is the R-value of 1 inch foam board?
The polystyrene is expanded. Styrofoam insulation is the cheapest material. R-values can range from 3.6 to 4.2 per inch.
Does polyiso insulation need to be covered?
Yes, polyiso roof insulation, like other roofing materials, should be protected from environmental conditions when staged on a job site and during installation. This is essential to ensure that the installed roof system is not compromised by moisture or other elements.
Can you layer polyiso insulation?
Multiple layering of the polyiso can add to the benefits of a multi-layered system in both fully mopped systems and systems that have the first layer of insulation mechanically fastened with successive layers mopped or adhered.
Is polyiso insulation waterproof?
After polyiso panels are manufactured, they are sandwiched in between exterior layers composed of recycled paper products and fiberglass. This creates its closed-cell structure and makes polyiso exceptionally waterproof.
