Flat Roof U Value 2017

The thermal transmittance or u value of the complete roof system is calculated in accordance with established international standards.

Flat roof u value 2017.

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. 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. Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated. 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.

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. 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. 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. All structural metal roofing systems having a thickness equal to or greater than 22 gage and all.