How far out should an external window sill be?

Ray Palmer

The title says it all "How far out should an external window sill be?".

I have a newish sill put on for the exterior of the window. It doesn't visually match the others for how far it comes out. It is now staining the wall when it drips. I know the guy who put it in is already saying no reg covers it. I reckon 60mm but he mentioned 30mm.

darrenking

Ray Palmer wrote: »

The title says it all "How far out should an external window sill be?".

I have a newish sill put on for the exterior of the window. It doesn't visually match the others for how far it comes out. It is now staining the wall when it drips. I know the guy who put it in is already saying no reg covers it. I reckon 60mm but he mentioned 30mm.

I'm a bricklayer by trade and fit them every day. The least I've ever left them out from external wall is 60mm for brick walls and 70mm for plastered walls. The drip of on your sill must be nearly touching your wall.

mickdw

Ray Palmer wrote: »

The title says it all "How far out should an external window sill be?".

I have a newish sill put on for the exterior of the window. It doesn't visually match the others for how far it comes out. It is now staining the wall when it drips. I know the guy who put it in is already saying no reg covers it. I reckon 60mm but he mentioned 30mm.

I suggest he is a cowboy unless you are talking about off standard stuff like pressed metal cill or something like that.
If you are dealing with 100mm blockwork outer wall, you should easily get 75 to 80 mm from face of block or as you say 60 mm from finished wall.
again I'm only guessing what your wall make up is but typically the upstand on the cill - the part the window sits on, should be behind the vertical dpc by 15mm or so to allow window be installed correctly.

Ray Palmer

mickdw wrote: »

I suggest he is a cowboy unless you are talking about off standard stuff like pressed metal cill or something like that.
If you are dealing with 100mm blockwork outer wall, you should easily get 75 to 80 mm from face of block or as you say 60 mm from finished wall.
again I'm only guessing what your wall make up is but typically the upstand on the cill - the part the window sits on, should be behind the vertical dpc by 15mm or so to allow window be installed correctly.

It is pressed metal as part of external insulation install.

Ray Palmer

Sorry does anybody know if because it is pressed metal is it different standard.

mickdw

To be honest, if the pressed metal cill has its drip on the outer edge, a smaller projection would be reasonable. Your typical concrete cill has drip built into the underside about 25 mm back from front.
Photos would tell alot.