Building Regulations for Roof Insulation

Roof insulation thickness for building regulations will vary depending on the type of insulation used. Used within a Bauder waterproofing system our products meet current UK Building Regulations Part B for fire protection.

Different insulants have different efficiencies and performance levels which affects the thickness required to meet building regulations. This table shows a comparison of the insulations when looking to achieve different U-values on a plywood deck.

Warm roof insulations

  0.11W/m²K on a plywood deck 0.13W/m²K on a plywood deck 0.18W/m²K on a plywood deck
Insulation Type Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
BauderPIR FA-TE 200 6 160 4.8 120 3.6
BauderPIR FA 200 6 160 4.8 120 3.6
BauderPIR FA G16 (average thickness) 200 6 160 4.8 120 3.6
BauderVIP TE* 110 17.9 80 17 60 13
BauderROCK 335 53.6 290 46.4 200 32
BauderGLAS 310 31 260 26 190 19

*U-value based upon ratio of 80% BauderVIP TE in combination with 20% BauderPIR FA-TE with an additional 30mm layer of BauderPIR FA-TE for 0.11W/m²K 


Inverted roof insulation

Key:
*1 layer
** 2 layers
*** 3 layers
BauderGLAS Inverted incudes a base layer of BauderGLAS T3+

Excluding correction in BS6229:2018 - 4.6.2.2 Inverted Roofs
  0.11W/m2K on a 150mm concrete deck with a lambda value of 2.500 W/mK 0.13 W/m2K on a concrete deck with a lambda value of 2.500 W/mK 0.18 W/m2K on a concrete deck with a lambda value of 2.500 W/mK
Insulation Type Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
BauderJFRI PREMIUM+ Hard Landscape 265** 7.95 225** 6.75 165* 4.95
BauderJFRI PREMIUM+ Soft Landscape 280** 8.40 240* 7.20 175* 5.25
BauderJFRI PREMIUM 300 Hard Landscape 280** 11.20 240* 9.60 175* 7.00
BauderJFRI PREMIUM 300 Soft Landscape 300** 12.00 255** 10.20 185* 7.40
BauderXPS 300 310*** 9.30 260*** 7.80 190** 5.70
BauderGLAS Inverted 360** 36.00 300** 30.00 220** 22.00

 

Including correction in BS6229:2018 - 4.6.2.2 Inverted Roofs
  0.11W/m2K on a concrete deck with a lambda value of 2.500 W/mK 0.13 W/m2K on a concrete deck with a lambda value of 2.500 W/mK 0.18 W/m2K on a concrete deck with a lambda value of 2.500 W/mK
Insulation Type Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
Thickness
(mm)
Approx Weight Loading
(Kg/m²)
BauderJFRI PREMIUM+ Hard Landscape 290** 8.70 250** 7.50 180* 5.40
BauderJFRI PREMIUM+ Soft Landscape 310** 9.30 265** 7.95 190* 5.70
BauderJFRI PREMIUM 300 Hard Landscape 310** 12.40 265** 10.60 190* 7.60
BauderJFRI PREMIUM 300 Soft Landscape 330** 13.20 280** 11.20 200* 8.00
BauderXPS 300 340*** 10.20 290*** 8.70 210** 6.30
BauderGLAS Inverted n/a n/a 320** 32.00 230** 23.00

 

England and Wales - Part L of Building Regulations - Convservation of fuel and power

Separate criteria are set out in approved documents; L1 is specific to dwellings and L2 relates to buldings other than dwellings.  These are then split into four sections and for new construction are based on notional buildings:
L1A New Dwellings - 0.13 W/m²K
L1B Existing Dwellings - 0.18 W/m²K
L2A New Buildings other than Dwellings - 0.18 W/m²K
L2B Existing Buildings other than Dwellings - 0.18 W/m²K
More via Government Planning Portal ►

 

Scotland - Section 6 of the Scottish Building Regulations - Energy

Revised target levels for roofs are to be implemented from October 2015 and are approaching or exceeding the passiivhaus standard for buildings.
Domestic buildings - 0.11 W/m²K
Non Domestic buildings - 0.18 W/m²K for heated and naturally vented notional buildings
Non Domestic buildings - 0.16 W/m²K for heated and mechanically vented notional buildings
More via The Scottish Government ►

 

Contact us today about your project

To learn more about building regulations or if you'd like to discuss your flat roof project, get in touch to arrange a meeting with your local area technical manager.