Flat Roof U Value 2017

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.

Flat roof u value 2017.

The thermal transmittance or u value of the complete roof system is calculated in accordance with established international standards. Backstop u values table 1 maximum elemental u value 1 2 w m2 column 1 fabric elements column 2 area weighted average column 3 elemental u value individual element or section of element roofs pitched roof insulation at ceiling insulation on slope flat roof 0 16 0 16 0 20 0 3 walls 0 21 0 6 ground floors3 0 21 0 6 other exposed floors 0 21 0 6. Typical constructions and u values assumptions the u values in the tables that follow have been calculated under a management system certifi ed to the bba scheme for assessing the competency of persons to undertake u value and condensation risk calculations using the method detailed in bs en iso 6946. Roof coverings installed on low slope roofs roof slope 2 12 in accordance with section 1507 shall resist impact damage based on the results of tests conducted in accordance with astm d3746 astm d4272 cgsb 37 gp 52m or the resistance to foot traffic test in section 5 5 of fm 4470.

U value has an inverse relationship to r value. All structural metal roofing systems having a thickness equal to or greater than 22 gage and all. 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 local only az arizona no statewide mandated r values phoenix 2012 iecc yuma 2009 iecc tucson 2012 iecc flagstaff 2009 iecc 2 r 20 2 r 20 2 r 20 5 r 20 state only. Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated.