New Roof Insulation Requirements

If part of a roof is too low to install insulation that meets the requirements then a less thick insulation product may be used in those low clearance areas.

New roof insulation requirements.

New rules and practical. Arkansas enery code for new building construction 3 r 20. Insulation puts the money back in your pocket by protecting your home from the elements and lowering energy costs. The information contained in this document is meant to be used as a quick reference guide for insulation levels across the united states.

Choose feldco roofing for your brand new roof. A minimum of a 30 astm felt should be used as an underlayment. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value. Synthetic underlayment may also be used in lieu of a 30 felt provided it is an acceptable substitute to the roofing manufacturer.

It is important to note when insulation is on the floor of the attic the space between the insulation and the roof deck must be vented to the exterior. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation. State applicable energy ashrae zone minimum r value state local. Insulation on the floor of the attic figure 1.

Insulation entirely above the roof deck directly below the roof deck or both above and below the roof deck. Iecc 2015 requirements by climate zone 3. R values can be higher for foam insulation and other advanced insulation systems. This insulation strategy has not changed in recent code iterations and is not discussed in this article.

Recommended insulation levels for retrofitting existing wood framed buildings. Existing 3 4 inches of insulation. Cavity fibrous or cellulose insulation can be installed at levels up to r 15 in a 2 inch x 4 inch wall and up to r 21 in a 2 inch x 6 inch wall. Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam.

Insulation must keep a distance of at least 25mm from the roof underlay in all parts of the ceiling roof area. Whether you re doing a weekend fix or folding it into a bigger home renovation insulating your roof will pay off for years to come. Insulation tight to the roof deck i e. With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.

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. Roof slopes 9 12 and higher will require a dry in with a minimum of 3 side laps 12 end laps. Minimum insulation r value requirements non residential above roof deck.