Insulation under porch floor?

[nuzuki]

I have some anti heave foam board left over from a recent project. This weekend I was going to concrete the new porch floor with around 8inches of concrete to get upto dpc. Would there be any advantages to throwing this board in and putting concrete on top?
Thanks for your help

 

[Ivor Windybottom]

It would add insulation and help absorb ground movement so why not, especially as you already have the stuff.

 

[nuzuki]

Thanks for your reply. Just to add this is the open cell foam a bit like an EPS sheet and not like the closed cell insulation stuff. Im not sure I can tread on this stuff without causing it to break unless I use a board to spread my weight and fill up half the area then move the board to do the other area. Still ok to use?

 

[noseall]

Thanks for your reply. Just to add this is the open cell foam a bit like an EPS sheet and not like the closed cell insulation stuff. Im not sure I can tread on this stuff without causing it to break unless I use a board to spread my weight and fill up half the area then move the board to do the other area. Still ok to use?

Yes.

 

[nuzuki]

Thanks for your advice

 

[Ivor Windybottom]

You'll need a level, smooth and compacted surface beneath it, otherwise it would get torn to bits by the weight of the concrete.

 

[nuzuki]

Yes I made sure the base was level. What is the minimum depth screed I can do, 20mm?

Thanks

 

[robinbanks]

20mm (of anything, but what do you mean by "screed"? Liquid? Concrete? S&C?) directly covering your foam is a bit skinny, I'd do 40 at least

 

[nuzuki]

The foam has at minimum 6inches of concrete on top. The screed would be for final adjustment prior to fitting a laminate floor. I was also thinking self levelling compound but have never used it myself

 

[Ivor Windybottom]

Check the specs of the self-levelling products you're looking at. They all have different recommended depths, most are quite low.

I've used it once, it's quite easy to use, you just need a paddle mixer and a powerful drill, or at least one you don't care about burning out.

 

[Dereekoo]

I've used it once, it's quite easy to use, you just need a paddle mixer and a powerful drill, or at least one you don't care about burning out.

But what if he does care about burning it out? whats plan B, buy one to burn out or mix by hand?

 

[Ivor Windybottom]

My old Bosch cheapo mains hammer drill got a bit smokey when I used it. But I didn't care as I already had a better cordless one. The £50 screwfix titan SDS one seemed to cope with tile adhesive recently, which is probably more challenging.

The proper way is to buy a mixer, which is specifically designed to be a low-speed high torque mixer rather than a high-speed low-torque drill. But that would be stupid for a little porch, or for most DIYers.

I doubt anyone would think mixing self-levelling screed by hand would be a good idea, or even suggest it.

 

[nuzuki]

Thanks for your help. I have a paddle mixer. Do I need a spiked roller?

 

[Ivor Windybottom]

I didn't bother when I did my garage, there were a small number of bubbles left after, so probably a good idea. If you're tiling then you can just pop/squash them after, they have no strength even after setting.