How Much Do Baffels Add To R Value Of Roof

The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13.

How much do baffels add to r value of roof.

Know exactly how much you need with our project calculators. You don t need much to hold them into place just enough to temporarily hold them until a bead of spray foam sealant applied along each edge sets up and does the permanent holding. All these have r values ranging from r 3 2 to r 3 8 per inch. High r value unvented roof assemblies will require a proportionally larger amount of insulation above the roof deck for condensation control.

Closed cell spray foam insulation. Fibers from recycled post consumer paper that are treated for insect and fire resistance. The most common blown in material used but it can rot and grow moldy if exposed to moisture. The higher the r value the greater the insulation performance.

By installing the baffles properly you can increase the r value all the way out to the exterior sheathing. But even if you don t see a huge financial return a new roof can make you more likely to get full asking price lower time on market and smoother negotiations. Insulation level are specified by r value. More insulation is needed above the roof deck in colder climates and where indoor relative humidity is above 35 in winter.

The higher the r value the better the thermal performance of the insulation. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. As listed in the definition above the baffle is meant to regulate the flow of air. A new roof can increase home value but you might not see a 100 return on investment very few improvements if any offer a full recoup of money spent.

Fibers from rock or recycled slag from blast furnaces. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Baffles establish a channel for air to circulate between the insulation and the roof sheathing. Generally 40 of the total assembly r value should be above the roof deck.

Recommended home insulation r values. Closed cell spray foam has a far better r value per inch than other less effective insulations like cellulose fiberglass or even open cell foam. For a very good introductory overview article on r value see r values over at the website of. R value is a measure of insulation s ability to resist heat traveling through it.

As with attic floor insulation moisture and heat removal are the reasons for creating proper air. Even with a 3 12 2 4 truss you are looking at a minimum r15 at the farthest edge. Stukinftw the rigid foam baffles can be fastened with angled nails or screws driven tight against the face of the foam and up into rafters on either side.