there are a number of points to consider here under the Building Regulations:
1. Escape: minimum provision to be considered
2. Thermal: Minimise heat loss and too much glass can lead to overheating
3. Ventilation: depends on type and number of windows normally 20% of floor areas should be windows that open 30 degrees, unless it is an escape route where it must be 90 degrees
4. Safety: window in a sloped surface must be 600mm above floor level or 800mm if in a vertical face. Below these heights safety glass is require.
As you can see there are a number of regulations to consider, if you would like further assistance, please feel free to contact us at info@jeremywedge.com where we can review your exact requirements.
