Window Sill Construction
 

What started out as a boiler install has now turned into a Bay Window
renovation. Quite how, I'm not sure.

Photos to amuse you:

http://tinypic.com/view/?pic=27x1qb6

http://tinypic.com/view/?pic=27x2aut


Okay so it seems I have a the original sills made from disintocrete, worst
still they are a 'solid' piece from out to in, all that was in front was the
lime plaster - long since blown out.

So it looks very much like I'm going to have to recast new sills (especially
after an over enthusiastic SDS session!) My aim was to remove the culprit
iron reinforcement. Which I've nearly done as you can see, if the frame
still stands afterwards a minor miracle (Acro what?) This bay does not have
an upper storey you'll be relieved to hear.

Anyhow I obviously don't want a cold bridge of such gargantuan or even any
proportions, so what's the proper construction?
I'm guessing recast the external sill to less of a depth add insulation and
something else load bearing to come to brick level inside. The brick will
be faced with 40mm insulated board. So what have I to play with? A double
skin of standard brick with zero cavity. What do I put between window frame
and the sill? Can I cast all 3 metres of sill in one go? And other similar
questions...

--
Mike W