Flat Roof U Value 2015

State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010 2 r 20 3 r 20 state local mo.

Flat roof u value 2015.

To comply with part l of the building regulations 2010 all roofs to rooms except those in unheated buildings should be thermally insulated to a maximum u value of of 0 18 w m k. Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated. U value has an inverse relationship to r value. 0 25 column a is for extensions where the existing dwelling s walls and roof u values are worse than 0 70 w m k in the walls and worse than 0 25 w m k in the ceiling.

Epdm rubber roof covering 19mm ply 50mm ventilated air layer protect vp400 plus lr membrane sip at specified thickness protect vc foil ultra insulating a vcl 25mm service void 50mm gyproc thermaline super. Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated. Flat epdm roof description. 0 25 column a is for extensions where the existing dwelling s walls and roof u values are worse than 0 70 w m k in the walls and worse than 0 25 w m k in the ceiling.

For the majority of flat roofs built up in a series of material layers each of a consistent thickness and performance the most appropriate calculation type is the combined method detailed in bs en iso 6946. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. For more information see our articles and how to videos below. R value of various materials.

Check our library of roof u value calculations. The thermal transmittance or u value of the complete roof system is calculated in accordance with established international standards. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Reference table for u values u value is the coefficient of transmission i e the transmission of heat through the materials which compose the building s envelope or outer shell.

For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09. Non residential above roof deck. These can be supported with a detailed report. R value state local al alabama 2015 alabama commercial energy code 2 r 25 3 r 25 state local ak alaska 2012 alaska building energy efficiency standard 7 r 35 8 r 35 9 r 40.

A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. Here s my 2 cents and insulation guide for a cold flat roof concrete slab floor internal stud wall and to find out what type and thickness of insulation. We provide u value calculations to show compliance with current building regulations standards and best practice.