Floating foundation for block garden shed!!

Bruce2008

Can anyone help me please... I have an existing wooden garden shed (8ft x 8ft) on a floating 4" concrete slab (8ft x 8ft with no reinforcement)... I want to build a block shed (8ft x 8ft again) on this base... I was hoping to put another slab of 6" on top of this with reinforced 10mm wire square grid... drill the existing base and fit bars to bond two bases together... This would give me a floating base of 10"...

Is this good enough to build a shed with 4" block wall having a gable height of 8ft reducing down to 6ft in the corners... overall length of each wall will be 8ft... I was considering using Quinn Lite blocks to reduce the overall weight of the walls...

I know the best option would be to dig out the base and put in proper foundations but the whole shed base is surrounded by decking and patios right up to the edge of the base so it would mean destroying the whole garden and starting from new...not really an option...


Hope someone can give me helpful advice...

Thanks

mickdw

I would cut back the slab around the edges and remove any soil down to a solid base as there is a fair chance that there is all sorts of crap left in place under the existing 4" slab. I would then pour a raft type structure with a deeper concrete section around the outside and the 6" slab on top of old should be fine.
Id use a wider wall than 4" too.

You could always make it alittle bigger if you didnt fancy cutting the slab.

Bruce2008

mickdw wrote: »

I would cut back the slab around the edges and remove any soil down to a solid base as there is a fair chance that there is all sorts of crap left in place under the existing 4" slab. I would then pour a raft type structure with a deeper concrete section around the outside and the 6" slab on top of old should be fine.
Id use a wider wall than 4" too.

You could always make it alittle bigger if you didnt fancy cutting the slab.

Thanks Mick for the reply...

Was kinda thinking I would have to go at the existing base... would I have to fan out the foundation as I go down or can I just do a foundation with straight sides?... also what width and depth would you recommend going down?... would it need reinforcing?... and finally would solid 4" block be okay if I had a pier at the gable... trying to keep the shed as big as possible... every inch counts ...

Sorry for all the questions but I scoured the internet for information and there is alot there for houses but not too much for block sheds...

Thanks again for the prompt reply... greatly appreciated...