Energy Nerd: What really matters is the Rvalue of the whole wall, not just that of the insulation. Open-cell spray foam has an Rvalue of about R-3.7 per inch, while closed-cell spray foam has an Rvalue that may be as high as R-6.5 per inch.

Then, how thick should spray insulation be?

“Normally, what we teach is that all foam applications should be installed in 3/4-inch to 3-inch-thick lifts. If foam is applied thick and quick — say, 4 inches thick — you gain yield. You can cover more wall with less foam. But the foam will be less dense.

Also Know, is spray foam insulation worth the money? The EPA's Energy Star Association has shown that monthly energy bills can be cut by up to 20% when air leaks are sealed and efficient insulation is installed. The initial cost of spray foam insulation is well worth the investment, when factoring in the overall savings that will be headed your way over the long term.

Herein, what is the R value of 2 closed cell spray foam?

Closedcell spray foam provides a higher Rvalue per inch (6.5) than less expensive insulation types like cellulose and fiberglass (3.5 to 3.7). Most spray polyurethane foam is called “two-component” foam.

What Does R Value Mean insulation?

Rvalue is a measure of resistance to heat flow through a given thickness of material. Rvalue is important, but it's just one of four key factors that determine the effectiveness of an insulation material.

Related Question Answers

Do you need a vapor barrier with spray foam insulation?

A. According to code requirements, a vapor barrier is required to be used with open-cell foam, but is not necessary with closed-cell foam. In the Northeast, the vapor barrier is required to be placed over the interior side of the insulation (the warm side of the wall).

Can mold grow on spray foam insulation?

As a product, spray foam insulation does not attract mold. And unlike wood or metal, spray foam does not rot, rust or deteriorate. This means that an area properly sprayed with foam insulation will never become a food source or a hospitable environment for a mold colony.

Why is spray foam so expensive?

Spray foam is more expensive for several reasons: 1) The material is a thermal plastic; a by-product of crude oil. As the price of oil goes up, so does the price of spray foam. 2) Essentially, it's a high performance product and the price reflects it.

Can I spray foam insulation myself?

A: Tom Silva replies: Spray foam is great insulation, but it's fairly demanding to apply; the kit instructions have to be followed exactly. In fact, study them before you buy your kit so you know what you're in for. As with sprayfoam kits, protect yourself and the floor from the dripping globs of canned foam.

What does spray foam not stick to?

Because of the properties of SPF (sprayed polyurethane foam) it chemically bonds with most substrates; cement, wood, stone, gravel, and brick. However, spray foam will not properly stick to a surface if the construction surface is wet or is retaining moisture.

How long does spray foam insulation last?

The International Association of Certified Home Inspectors states that spray foam insulation, wrap tape and housewrap insulation can last for more than 80 years. At the same time, cellulose, loose-fill, foamboard, loose fill and rock wool insulation can last up to 100 years.

Is spray foam better than fiberglass?

Spray foam insulation fills all spaces, preventing air from escaping. It acts as an air barrier. Like cellulose insulation, spray foam insulation is significantly more efficient than fiberglass and has a higher R-value.

What is better open or closed cell insulation?

Closed cell foam has a higher R-value than open cell foam, usually about 6.0 per inch. This higher rating makes closed cell foam better at keeping heat in or out of a structure. Open cell foams have an R-value of around 3.5 per inch.

Does spray foam lose R value?

When first installed, the Rvalue of closed cell spray polyurethane foam is actually about 10 for a one-inch thickness. Industry experts suggest that other types of insulation, especially those that can absorb moisture and “mat down” can suffer huge and permanent (up to 50%) Rvalue loss over time.

Can you spray foam the underside of your roof?

Open- or closed-cell spray foam is applied to the underside of the roof sheathing, and additional fiberglass or cellulose insulation is blown in as a cost-saving method for meeting high insulation requirements and filling in the cavity space between the rafters to the ceiling deck.

Should I spray foam my attic?

Spray foam insulation is an incomplete name. It really should be called spray foam insulation and air barrier. A properly done spray foam job not only insulates but also greatly reduces the air leakage of a home. If you leave the existing insulation in the attic, it interferes with the foam installation.

What should the R value be for exterior walls?

Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces. See the Department of Energy's (DOE) ranges for recommended levels of insulation below.

What is the R value of 2 inch foam board?

Choose the right type of rigid foam for your needs

Polyisocyanurate: Known as polyiso for short, polyisocyanurate foam has the highest Rvalue per inch (R-6.5 to R-6.8) of any rigid insulation. This type of rigid foam usually comes with a reflective foil facing on both sides, so it can also serve as a radiant barrier.

Is spray foam insulation waterproof?

Is Spray Foam Insulation Waterproof? Open cell foam is not waterproof or water-resistant. In contrast, closed cell foam is water-resistant. However, only high-density closed cell foams are waterproof.

What is the R value of 3 inches of spray foam?

In regards to closed-cell sprayed in foam insulation, Rvalue can range between R-4.9 to R-7.1 per inch. Closed-cell insulation products, such as Icynene ProSeal, allow builders and architects the ability to achieve R-21 in a three inch pass.

What insulation has the highest R value per inch?

Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.

Do you need attic ventilation with spray foam insulation?

Most installations of spray foam insulation, when properly installed, act as an air barrier. When you use it instead of the fluffy stuff (fiberglass, cellulose, cotton), a house will be more airtight. That's good. Well, source reduction and separation would come first, but airtight homes need mechanical ventilation.

What are the pros and cons of spray foam insulation?

The “pros” of installing spray foam insulation
  • air leakage is virtually eliminated.
  • an air-tight seal prevents heat loss.
  • home energy efficiency is assured.
  • seasonal energy bills are lowered.
  • ideal for attics, roofs, walls, floors.
  • higher R-Value than other installs.
  • moisture accumulation is reduced.

How much do spray foam installers make?

The average Spray Foam Installer salary in USA is $40,950 per year or $21 per hour. Entry level positions start at $27,300 per year while most experienced workers make up to $69,615 per year.