How Much Do Baffels Add To R Value Of Roof

The higher the r value the greater the insulation performance.

How much do baffels add to r value of roof.

More insulation is needed above the roof deck in colder climates and where indoor relative humidity is above 35 in winter. The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Fibers from recycled post consumer paper that are treated for insect and fire resistance.

For a very good introductory overview article on r value see r values over at the website of. You should of course see the manufacturer provided technical data sheet for the r value of specific products. R value is a measure of insulation s ability to resist heat traveling through it. Insulation level are specified by r value.

Baffles establish a channel for air to circulate between the insulation and the roof sheathing. Fibers from rock or recycled slag from blast furnaces. 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. Closed cell spray foam insulation.

R value measures how well certain building insulation materials can resist heat. Generally 40 of the total assembly r value should be above the roof deck. Know exactly how much you need with our project calculators. R value of various materials.

All these have r values ranging from r 3 2 to r 3 8 per inch. As listed in the definition above the baffle is meant to regulate the flow of air. The most common blown in material used but it can rot and grow moldy if exposed to moisture. 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.

As with attic floor insulation moisture and heat removal are the reasons for creating proper air. By installing the baffles properly you can increase the r value all the way out to the exterior sheathing. High r value unvented roof assemblies will require a proportionally larger amount of insulation above the roof deck for condensation control. The higher the r value the better the thermal performance of the insulation.

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. When determining how much insulation you need don t guesstimate calculate. Even with a 3 12 2 4 truss you are looking at a minimum r15 at the farthest edge.