Minimum size roof window

20 Feb 2007
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United Kingdom
About to fit a top hung Velux type roof window and wanted to know the minimum size the window can be but still conform to building regs. The window will be the only window in the bedroom of a dormer bungalow on the first floor and so will be the sole means of escape in a fire etc.

I'm hoping for 78x98 with top hung 45deg opener.
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Great excellant link thankls for info.

For emgergancy escape they specify:

'however it should be noted to produce the required opening area a minimum 750mm x 450mm opening must be provided' so a 980x780 should be fine here.....


Room size is 6.32m2 so 1/20th is 0.316m2. My roof window would be at least 0.3375m2 so should be fine here??
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