Suspended timber floor

[StevenM]

Hi all,

 

what is required under a suspended timber floor for an extension? Is this over site?

 

Reading online I think over site is hardcore, sand blinding and then concrete.

 

I am a complete novice and I am trying to project manage my extension. I think I may need to sack the builder and start taking a more hands on approach as the work is not to standard

[SimonD]

You don't need hardcore, sand blinding and then concrete. All you need is a sufficient cover of inert material so a good spread of hardcore or a lean mix of concrete cover - 50mm concrete should be sufficient. Then just make sure you've got a min 150mm distance between the bottom of your joists and finished level of oversite.

[Canski]

And that it is well ventilated. 

[TonyT]

Agree with all the above!

 

[StevenM]

On 15/10/2022 at 14:49, SimonD said:

You don't need hardcore, sand blinding and then concrete. All you need is a sufficient cover of inert material so a good spread of hardcore or a lean mix of concrete cover - 50mm concrete should be sufficient. Then just make sure you've got a min 150mm distance between the bottom of your joists and finished level of oversite.

I presume soil is not allowed.  

[Nickfromwales]

10 hours ago, StevenM said:

I presume soil is not allowed.  

It’s what is under 100’s of 1000’s of floors, but not ideal tbh on a ‘new’ job. Some sort of water / vermin barrier is recommended, such as the 50mm of concrete cap. You can get a concrete lorry to deliver this ready mixed and just have 2 barrows to relay it from street to site. The lorry will need to be ordered to allow for the wait time for you to hand-ball it in, unless you can get it poured straight in and then just rake it around?