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.
Flat roof u value 2016.
The thermal transmittance or u value of the complete roof system is calculated in accordance with established international standards.
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.
Then simply adjust the thickness or the u value until you are happy and the calculator will do the rest.
R value state local al alabama 2015 alabama commercial energy code 2 r 25 3 r 25 state.
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.
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.
State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1.
Check our library of roof u value calculations.
State only ca california 2016 building energy efficiency standards 2 r 25 3 r 25 4 r 30 5 r 30 6 r 30 state local co colorado 2012 iecc.
Providing you with instant calculations all day everyday with step by step options and hints and tips along the way the no jargon u value calculator takes you through your construction build up until each element is included.
If you have a target u value in mind then the calculator will give you the thickness of insulation needed.
Ecotherm s u value calculator is simple to use easy to tweak and provides an instant u value.
Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated.
As with the chart the roof build up includes paving slabs a water controlling layer insulation 7 5mm holt melt waterproofing and a 200mm reinforced concrete deck.
This u value calculator covers all the main ways of building walls flat roofs pitched roofs and floors using kingspan insulation.
Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated.
A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value.
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.
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.
U value has an inverse relationship to r value.
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.
