Position of window frame WRT wall

Looking at the relplacement windows at various houses in our road, I have noticed a wide variation in how the replacement window frames have been positioned by the companies involved.

In many cases the frame of a bay is positioned further into the house than the origonal was. On one house the sill is not even protuding enough to drip water away from the wall.


With a non bay window, the postition of the frame will be dictated by the fitters' judgement and the sill size, but with a bay window, the posistion will be dictated by the overall size that is was built to at the factory.

So far I have not been able to find guidelines to how windows should be postioned.

Does anyone know of a source of info on this subject?

The frame position is normally governed by the wall below, and also by the design at the reveals - ie the position of the vertical DPC

This will determine whether the internal or external face of the frame is aligned with the external corner of the reveal

^woody^ said:

The frame position is normally governed by the wall below, and also by the design at the reveals - ie the position of the vertical DPC

This will determine whether the internal or external face of the frame is aligned with the external corner of the reveal

Click to expand...

'fraid that went over my head, this is a solid 9" brick wall house and this is the only wall type I have expereince of, there are no vertical DPCs and can you beleive I don't even know what a reveal is. I will need to look it up later.