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Building Regulations - Required U Values

Document L 2010 England - Effective 1st October 2010
Document 6 2010 Scotland - Effective 1st October 2010

The overall window U Value of at least 1.6 represents an insulation Value of the whole window including the frame and double glazing therefore any overall window U Value less than 1.6 is acceptable.

Any window frame manufactured in timber has a U Value well in excess of 1.6 and it is therefore necessary that the double glazing must have a U Value well below 1.6 to compensate for the much higher timber U Value exceeding 1.6, however building control may allow relaxation in certain circumstances.

Listed Buildings
It should be noted that Listed Buildings are exempt from their regulations. Similarly these regulations do not apply to any windows Listed or otherwise, where the single glazing is being replaced by Slimlite Double Glazed Units, for new or replacement windows in Listed Buildings.

Slimlite Self Cleaning Double Glazed Units, 10mm, 11mm, 12mm featured in Grand Designs. U Values UKAS Certified - BSEN1279 Certified. Unique 5mm perimeter seal depth - Georgian windows. From any distance look like single glazing.

By using and maximising the latest technology it is possible to construct a double glazed unit with very small cavities or space between the glasses with a 5mm perimeter seal depth and selected insulating inert gas cavity to obtain U-Values to comply with Building Regulations and comparable or better than U-Values obtained by standard units with much wider cavities.

Slimlite Self Cleaning Double Glazed Units are constructed with a 4mm clear outer Self Cleaning pane with a selected cavity of 4mm, 5mm or 6mm, the wider cavity, increases the insulation, with selected cavity insulating inert gas, which only performs in smaller cavities, and inner pane of 4mm Low Emissivity glass.

The emissivity coating is on the inside face into the cavity and reflects the long wave rediation or heat back into the room. The warm edge technology perimeter spacer incorporated, ensures insignificant differential insulation value between the edge and the centre of the glass.