Rigid board insulation offers a high R-value in a slim, lightweight product. Due to its firm structure, rigid board insulation will not shift during installation like batt or blown insulation. Rigid insulation is easy to cut, and it can be used to cover large wall spaces quickly. It is also commonly used to prevent thermal bridging by covering the exterior of the home’s frame and sealing any gaps in a building’s internal insulation.
Rigid board insulation requires careful finishing with seam tape and spray foam to prevent air and thermal leakage. Depending on your project specifications including insulation capacity, climate, and budget, you can determine which rigid board insulation product meets your needs.
Made with various lightweight petroleum-based materials, foam board is pest-proof, air-proof, and waterproof. It is often a popular insulation choice for basements. Foam board insulation installation also typically includes seaming with foam insulation spray, seaming tape, and caulk. The three most common types of foam board insulation are expanded polystyrene (EPS), extruded polystyrene (XPS), and polyisocyanurate (ISO). There is also phenolic foam board insulation, which is a relatively newer product.
Similar in appearance to common styrofoam, EPS has the lowest R-value of foam board insulation types at R-3.8 per inch. It can be damaged more easily than the other types of foam board, but it’s very cost-effective, making it a budget-friendly option. EPS does not block water vapor and can be susceptible to pests if it is not pre-treated.
XPS offers a higher R-value than EPS – usually around R-5 per inch. Depending on its exterior finish, XPS may be considered a vapor retardant but not necessarily a strong vapor barrier. It is more durable than its extruded counterpart though also slightly more expensive. Ultimately, XPS is a good mid-value option.
It is important to note that many environmentally-conscious builders avoid XPS and EPS because a blowing agent used in its production process may contribute to harmful greenhouse gas emissions.
With the highest R-value of the foam board types, ISO achieves a rating of around R-6.8 per inch. Polyiso is surfaced with a reflective foil finish, which means it can also serve as a radiant barrier. ISO is slightly more expensive than other rigid foam insulation types but is also less toxic and has a production process that is generally less harmful to the environment.
Also called “rock wool,” mineral wool rigid board insulation is often favored by environmentally-minded companies and homeowners. It has soundproof and fireproof properties, though it is important to note that it is not airproof or vaporproof. Natural fiber board insulation contains no petrochemicals and is often made from recycled materials or hemp fiber. Despite its eco-friendly makeup, mineral wool and fiber board insulation do require PPE during installation because they can shed irritant particles.
Rigid fiber insulation provides excellent fire resistance, making it a good choice for structures that might otherwise be fire-prone. However, rigid fiber insulation is not a substitute for fire extinguishers, sprinklers, and other fire safety measures even though it can withstand high temperatures. It can also be layered on top of batt insulation to add R-value. Rigid board insulation is often installed to enclose or “wrap” the frame of a building to prevent thermal bridging.
Rigid foam board insulation is relatively easy to work with, but homeowners should be aware of a few key installation steps. Every seam between boards needs to be sealed thoroughly to prevent air leakage. Building codes generally require that foam insulation be protected with gypsum drywall. This is often accomplished by framing a two-by-four wall inside of the insulation. Proper installation of your rigid board insulation will determine its effectiveness, so it’s best to hire an expert.
If you’re looking for rigid board insulation installation experts in your area, contact your local TruTeam branch. As a leading installer of insulation in the nation, we have a network of nearly 200 branches located throughout the country. A local TruTeam installer can help determine the best rigid board insulation product for your project. Let us provide you with a free estimate today!