casting sills

chrisinwestcork

hello everyone im chris and new to boards.ie
im at the stage of a self build and need some help,i have a window thats about 27' long and need to cast a sill any info on how to do this?
its on a 100 mm cavity with block peirs at both ends and 2 box section supports inbetween,cavity will be pumped so this has to be done first, oh and a stone front just to make it more interesting! the stone is not up yet i think i should wait but its at eye level so it has to be perfectly straight and level, any info would be great
thanx chris

smashey

chrisinwestcork wrote: »

i have a window thats about 27' long

That's fecking huge. :eek:

Quazzie

Would ya consider buying three or four smaller cills and just jointing them as is commonly done in bay window construction

chrisinwestcork

i did think of that but as they are at eye level if they were not perfectly in line as in ,with eachother, the stone wall, end pillars or windows(already fitted) it would look like dogs c..... lets just say i would notbe happy! thanks for the reply its a tricky one but its part of the design so i think casting is the way to go!

Mellor

27' is monstorous, over this lenght, the tolerance on casting concrete is considerable.
I think the best way to approach it is to use separate pieces, and line the joints up with the mullions on the window, (I hope to god you have at least one)

chrisinwestcork

wow this site is good so many replys and i only joined today! wish i joined be4 the block layer and his bent level! or the ground workes lol
ok sorry for my lack of building terms but wots a mullions? i cant seem to upload a pic of the place would that be caus im a new member?

blackiebest

A 'mullion' is a vertical as opposed to horizontal (transom) divide in a window.

Is your window a radial bay or oriel window?





www.truewindows.ie

chrisinwestcork

its just a straight window 27 ' long and about 3' high, kinda flush with the outside leaf of the block work and also has 2 100mm box section uprights sorry mullions(u lot will make me sound like a builder soon...) thanx for ur in put guys,if any one needs help with welding issues i hope i can help!!

LoopyBum

... what are you doing for a lintel for that ape of a window? I had to put an RSJ in over a bay window...

chrisinwestcork

hello i made a steel frame using 100mm box section as its only supporting the rafters for the roof

No6

You have to make a timber form or shutter to cast a cill however with one that long you will end up with joints in the formwork and therefore in the resultant cast cill so maybe re consider pre cast cills!! what have you used on the rest of the house? ie if the rest of the cills are precast it may look slightly odd to have a cast cill beside it! if you havn't any cills in at all and you've loads of money consider natural stone cills, when done correctly you can have a very fine joint in stone.