building a load bearing wall on a concrete slab

[DIYbuilder]

Hi, I'm in the process of converting a bungalow into a chalet and would like to build an internal wall that will also support the first floor joists and perhaps the roof

I think I may need to dig a channel through the existing solid concrete floor and pour a strip foundation but wanted to see if there were alternatives.

I haven't determined the thickness of the slab but believe it to be 4 inches thick and not reinforced below the slab is 6 inches of compacted hardcore.

if I find it is reinforced or thicker can I build straight off it?

Thank

 

[RedHerring2]

Highly unlikely, I'd say. Your BCO will want at least an exploratory hole, and he'll probably say no outright.

 

[^woody^]

With this significant conversion, are you making it up as you go along or are there any plans, designs and engineers involved?

Anyway, your only alternatives are to span a beam across to support whatever needs supporting, or to use different joists which span longer distances and don't need support in the middle

 

[DIYbuilder]

Thank you gents,

I'm still at the planning permission stage.

I'd thought about the beam approach but am looking to reduce the use of high value materials (RSJs) and consultant fees where possible (limiting it to where its absolutely necessary and can't be designed out).

I built a fairly large extension last year and just worked with the BCO who was a great help. last time the build was two storey with a gable roof designed by the truss manufacture, all done without a structural engineer calcs and signed off by BC.

I haven't engaged with them just yet but remember the BCO saying that this was an option on the last build.

For the costings I'm working up I feel the most cost effective option is to carve up the ground floor (38ft x 24ft) concrete slab and pour approx 50 linear ft of strip foundation.