Cantilevered 1st floor

just do it

Folks
Currently designing a 2 storey new build and the architect has come with a great design we really like. One of the features is the Southern and Western aspects of the top floor will jut out 1m over the downstairs. We're looking at a block build with concrete floors.

My query is, will this add much to the cost? Is it easily done?

FesterBeatty

Please tell me you have a structural engineer?!

If so, I'd rely on his advice rather than the internet when it comes to the design of cantilevers...

<snip>

just do it

FesterBeatty wrote: »

Please tell me you have a structural engineer?!

If so, I'd rely on his advice rather than the internet when it comes to the design of cantilevers...

<snip>

Well I think if I'm going to have an architect on board I'm also going to have an engineer on board.

I'm just putting this up here to get an idea as at this stage we are just at first stage drawings and there will be a few twists and turns before the final drawings.

sydthebeat

just do it wrote: »

My query is, will this add much to the cost?

thats a relative question, and depends on the design.

just do it wrote: »

Is it easily done?

yes. concrete precast slabs can simply be cantilevered. Obviously you need to get structural advice on this detail.


I always feel design features like these defintely are worth more on the completed project than the actually construction costs, once they work in the overall language of the design.

writhen

You should also consider incorporating thermal break balcony connection systems into your design. If going the precast route, your precaster can incorporate them into the balcony.

<snip>

just do it

sydthebeat wrote: »

thats a relative question, and depends on the design.



yes. concrete precast slabs can simply be cantilevered. Obviously you need to get structural advice on this detail.


I always feel design features like these defintely are worth more on the completed project than the actually construction costs, once they work in the overall language of the design.

Thanks Syd.
The design is straightforward enough and looks fantastic. I've a good structural engineer lined up as well which the architect works well with. I'll get the architect to ask the engineer about it cost wise before he develops the drawings further. I don't want to turn around at final drawings stage and say "take it out, it's too dear"!

bruschi

just do it wrote: »

Thanks Syd.
The design is straightforward enough and looks fantastic. I've a good structural engineer lined up as well which the architect works well with. I'll get the architect to ask the engineer about it cost wise before he develops the drawings further. I don't want to turn around at final drawings stage and say "take it out, it's too dear"!

without wanting to get into specifics of the engineering side of things, but realistically if you are already using precast slabs, then there may not be any additional cost at all. It is probably subject to the design etc, but I know I have a 1.2m overhang in a hollowcore slab, and there was no additional cost other than the extra slab and screed etc. The walls were already on solid foundations to take the slab, and are a 215 thick solid wall, which was more than enough to take the cantilevered effect of the slab. The only other cost was finishing the front face of the overhang in ply and plaster, which was about 300mm high.

in summary, I have a cantlievered overhang of 1.2m, and it didnt cost anymore on the structural end of things