What size?

macadam

What size cills do I need for 12"/300mm cavity and 7"/175mm stone facing, I ordered and bought cills 320mm depth but my stone mason says they are wrong.

Mellor

The traditional detail for the cill is to have it bridging the cavity and slightly resting on the inner leaf, and 50-75mm projection past the outer face.

So in your case you would need 100 cavity + 100mm blok outer + 175 facing + 50to75mm projection. Or 425-450mm. I'm gussing you forgot about the cavity.

They still may be usable, but will need to be detailed carefully. I'm guessing you don't have a professional involved at this stage

sydthebeat

Bridging the cavity with a cill is no longer an acceptable detail.

The cill needs to rest on the outer leaf, and, in the case of stone cladding, will be bolted to a mild steel L bracket which is bolted to the wall.

so again, assuming a 50mm projection that leaves the inner face of the cill basically on the inner face of the external blockwork. This would work in my opinion as the inner face of the window frame should also be on this level... affording a wide window board, and a well insulated cill detail.

macadam

Cills I got are fine, I still have 80mm projection, we sorted it out with a mix of Polish and English language and the odd feck sake..

Mellor

sydthebeat wrote: »

Bridging the cavity with a cill is no longer an acceptable detail.

But I wonder how many of the houses built from planing drawings by just a local builder who "knows what he's doing", and without a professional involved are these traditional detail.

Not fond of using that phrase, maybe obsolete is better

heavydawson

If bridging the cavity is no longer acceptable, can you give me an idea of where the inner edge of a cill should end assuming the following:
175mm cavity
100 concrete outer leaf
?

Slig

The outer leaf is the same size and the dpcs will still be in the same location so, providing the DOE are happy with it, the cill will be resting solely on the outer leaf with no contact with the inner leaf.

Is this what you are saying syd?
(attached PDF)