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U Value Insulation information

1st October 2010: There are now different requirements for Replacement, Extension and New Build frames and doorsets.
Understanding that there IS a difference we have to know the project type to give the best quotation & price compliant product.

U-VALUE AND WHAT IT MEANS TO YOUR PROJECT

The following information summarised from Building Regulations Documents L1A (New Dwellings) 2010 & L1B (Existing Dwellings) 2010.

Fitting (a) Standard for new fittings in new dwellings (b) Standard for replacement fittings in an existing dwelling
Window, roof window and roof light U-Value = 2.0W/m²K U-Value = 1.6W/m²K or Window Energy Rating = Band C
Doors with more than 50% of their internal face area glazed 2.0W/m²K 1.8W/m²K (or exempt if fitted into existing door frame)
Other doors 1.8W/m²K 1.8W/m²K (or exempt if fitted into existing door frame)

The following is general advice given by Jeld Wen:

What does it mean to our customers?

Part L 2010 Doors

Replacements & Doors in extensions (to existing dwellings)

  • Maximum U-Value = 1.8 W/m²K where glazed area of door is less than 50% and fitted into a new frame. Exempt if fitted into existing frame.
  • Maximum U-Value = 1.8 W/m²K where glazed area of door is greater than 50% and fitted into a new frame. Exempt if fitted into existing frame.

New build: Determined by Building Design

  • U-Value (range) = from 1.1 up to 2.0 W/m²K (weighted average). We recommend that you consult with your architect for clarification.

Non Thermal Break (between a house and a heated porch)

  • Exempt as insulation in this situation is not a requirement. The insulation comes from the porch door/windows.

Part L 2010 Windows

In simple terms:

Replacement windows

Maximum U-Value = 1.6 W/m²K or an Energy Rated window C or better (where A is best).

Extensions (excluding conservatories) to existing buildings

Maximum U-Value = 1.6 W/m²K

New build: Determined by Building Design

U-Value (range) = from 1.1 up to 2.0 W/m²K (weighted average).

Summary (for doors)

Is it a replacement? – Maximum U-Value of 1.8 W/m²K

Is it an extension to an existing building? – Maximum U-Value of 1.8 W/m²K

Is it a new build? – The customer must provide the U-Value but maximum allowable 2.0 W/m²K

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