Granny flat NSW on top of swimming pool

Good afternoon!

We are planning to build a granny flat by closing down the concrete pool and build on top of it.

What my builder is suggesting, remove all the concrete from the pool, clean fill with soil and compact it. Then put a 600mm deep piers on compacted pool ground, then build a brick venner granny on top!

Here is my worry, the builder suggests after compact the pool, he reckons it will become like normal ground....then they put a piers which is 600mm deep or two foot deep, then concrete slab on top it
and then build a brick veneer granny flat ....

Could anyone with the civil engineering background or builder please suggests, is it ok? Is this ok to have a piers 600mm deep on compacted pool and then build a brick venner granny on top?

Your help and knowledge is very much appreciated.

Thank you!

 

Yes this is fine and it’s standard building method. Obviously the new fill in the pool hole will have to be compacted properly. Engineer will design all that anyway nothing to worry about.

 

Could always opt for deeper piers. Or build it on stumps and afterwards enclose the outside and use it as storage.

 

Thank you for your reply.

do they add anything like cement or any chemical to the soil in order to help the compaction.

or just the soil?

 

Hi Kabali, so how did it go? did you remove the pool and fill it, then build the granny flat in the end?
As want to do the same thing. Is your project based in Sydney?

 

yes in Sydney, still the swiming pool is sitting there like a duck, but green...

 

Hi Kabali...!!!
I’m having a plan to build a Granny Flat on top of swimming pool...!!! Have you built it yet..??? Can you please give me some experience about it..???
I’m really appreciate that..!!!

 

It could be the only GF with a basement or bomb shelter or cellar.

 

Your demolition contractor or structural engineer can supply a compaction certificate after filling in the pool. Have designed big houses with half of it hanging over the old pool and never an issue.

If there are major concerns about movement, foundations and uncomfortable with the bore depth, maybe try screw piers. Its torqued to engineers specs to ensure there is no movement and you are not really removing spoil either.

 

I'd be putting a glass floor in the granny flat , stocking the pool with various fish , and selling tickets to the neighbours kids ....

 

Council usually expect rehab not repurposing. Council need development approval for its removal and for GF anyway as a consequence. (NSW) A geotechnical engineer will need to provide a report with the application. No big drama beyond cost. The pool fence will be a bigger drama - Until its finally inspected prior to new build.