No Concrete floor slab

[Croccy]

Can I put a floor slab (30m sq) down without a 100mm concrete slab? 

Using more MOT, 250mm? Insulation & Screed on top?

I know it can be done this way on refurbs!

[jayc89]

Unless spec'd by an Engineer BCO wouldn't sign that off. 

[Iceverge]

4 hours ago, Croccy said:

Can I put a floor slab (30m sq) down without a 100mm concrete slab? 

Using more MOT, 250mm? Insulation & Screed on top?

I know it can be done this way on refurbs!

 

It can be done with OSB in lieu of screed.

 

Compact the stone base well and get it dead level. It may need to be laid in several layers to achieve this. 

 

Install a layer of EPS. 

Install your DPM.

Another layer of EPS with all joints crossed. 

 

Install 18mm OSB with a suitable expansion gaps. 

 

Glue and screw another layer of 18mm OSB on top. With all joints well staggered. 

 

Tape the edges of the OSB to the walls to prevent any air or water leaks into the floor. 

 

 

 

 

[Roger440]

37 minutes ago, Iceverge said:

 

It can be done with OSB in lieu of screed.

 

Compact the stone base well and get it dead level. It may need to be laid in several layers to achieve this. 

 

Install a layer of EPS. 

Install your DPM.

Another layer of EPS with all joints crossed. 

 

Install 18mm OSB with a suitable expansion gaps. 

 

Glue and screw another layer of 18mm OSB on top. With all joints well staggered. 

 

Tape the edges of the OSB to the walls to prevent any air or water leaks into the floor. 

 

 

 

 

 

Very interesting. Thanks for posting.

[G and J]

1 hour ago, Iceverge said:

 

It can be done with OSB in lieu of screed.

 

Compact the stone base well and get it dead level. It may need to be laid in several layers to achieve this. 

 

Install a layer of EPS. 

Install your DPM.

Another layer of EPS with all joints crossed. 

 

Install 18mm OSB with a suitable expansion gaps. 

 

Glue and screw another layer of 18mm OSB on top. With all joints well staggered. 

 

Tape the edges of the OSB to the walls to prevent any air or water leaks into the floor. 

 

 

 

 

I think you’ve just solved a dilemma I have with my pigpen (man cave, thing).  Brilliant.

[Mike]

6 hours ago, Croccy said:

Using more MOT, 250mm? Insulation & Screed on top?

To do it in accordance with the Regs, you'd want MOT (or other suitable crushed stone), sand blinding, DPM, insulation as needed, 100mm concrete on top. Not forgetting the perimeter insulation.

[G and J]

34 minutes ago, Mike said:

To do it in accordance with the Regs, you'd want MOT (or other suitable crushed stone), sand blinding, DPM, insulation as needed, 100mm concrete on top. Not forgetting the perimeter insulation.

My 25m2 garden building doesn’t have to comply with regs and we won’t be throwing money at it as it is just a man cave, but I still want it nice and useable.  
 

This idea would solve my ‘getting concrete down the bottom of the garden after we’ve built the house’ problem.  I’m keen.