Minimum Roof Insulation Thickness

In ohio which uses the 2017 ohio building energy code will need to meet or exceed an r 25.

Minimum roof insulation thickness.

It takes into account the size of the sample and the overall change of temperature over time so that you can compare thermal conductivity of materials tested with plates of different temperatures or even that were tested by other methods. To get to an r 25 you ll need to install an average of around 4 inches of spray foam. When builders ask for advice about installing rigid foam on the exterior side of a wall i usually refer them to one of my articles calculating the minimum thickness of rigid foam sheathing the article explains that the r value of the rigid foam layer needs to be high enough to keep the osb or plywood sheathing above the dew point during the winter. Spray polyurethane foam has an r value of 6 6 per square inch of thickness.

This exception will allow the minimum thickness to be 4 2 at the low point or 5 2 4 away from the drain on a per foot tapered system. 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. The importance of insulation thickness r value isn t just a time measurement though. Basement walls require a minimum of either r 10 continuous or r 13 batted insulation.

Basically 4 of insulation is required with the only exception at roof drains. 877 775 1769 hunterpanels com 0716. X 6 6 r value r 26 4. Zone 6 requires an r 30 minimum which is 5 2 thick.

At roof drains the 4 of insulation can taper down to 3 within the area of the drain sump. The minimum roof insulation is a significant change from the average roof insulation we are familiar with using. You can see from the table that the recommended thickness of loft insulation is currently 270mm. Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam.

Hunter panels roofing tech topic r105 15 franklin street portland me 04101 888 746 1114 fax. The minimum thickness of insulation directly over fluted steel decks shall be a minimum of one half the nominal flute width. If structural sheathing covers 40 or less of the exterior continuous insulation r value shall be permitted to be reduced by no more than r 3 in the locations where structural sheathing is used to maintain a consistent total sheathing thickness.