Perfecting a floating floor

[0Floz0]

Hi,

Keen not to cowboy this part of my build so looking for some advice. Seems impossible to find anything on school of youtube but maybe i'm using the wrong terms.

Room is small, so 2.1m x 4m. Will be used as an office/gaming room. Desk and a sofa will be the heavy furniture.

Floor construction (top to bottom layer):

Laminate
Underlay
Chipboard 22mm T&G
(Some sort of slip layer or vapour layer at this point?)
EPS70 75mm
EPS70 75mm
EPS70 75mm
DPM
Concrete slab

I'm constructing a floating floor, so solid concrete base (3+inches deep). Then will be using EPS70 to build up what is a 225mm gap. So it'll be 3 layers of 75mm EPS. I'm nervous about using 3 layers but assume as long as I mix the pattern up so joins don't sit on joins below I should be ok?

I seem to read a lot of bad stories about floating floors but hoping thats more down to poor construction than anything else...

On top of the EPS will be 22mm T&G chipboard, then some underlay and finally some laminate. Do I need something between the EPS and the chipboard? Guessing some sort of vapour control layer? Would the roll of tyvek housewrap i've got suffice or is it likely to break? Would I need a slip layer so the insulation doesn't squeak?

Any other advice for construction? I assume I need a 10mm gap between the wall and chipboard. Does the laminate then overlay this exactly as that also needs a 10mm gap.

Thanks all

 

[23vc]

I’d ensure the slab is bang on flat before putting the insulation on, as any issues will manifest themselves when you do the laminate. I’ve done these without a VCL, foil taping the joints will probably do, but I’m sure others will be along with the science.
You also likely want another dpm below the slab.

 

[0Floz0]

I’d ensure the slab is bang on flat before putting the insulation on, as any issues will manifest themselves when you do the laminate. I’ve done these without a VCL, foil taping the joints will probably do, but I’m sure others will be along with the science.
You also likely want another dpm below the slab.

Thanks. Forgot to say there is a dpm below the slab. It’s already in place as I’m converting a garage. Though they’ve not brought it up to the dpc so I’m getting damp spots round the edges. But that’s why I’m putting another dpm down on top of the slab.

So you can tape the joints even though there isn’t any foil on the EPS?

 

[23vc]

Sorry, missed the fact that it wasn’t PIR. Yeah I’d assume you want a VCL then.

 

[noseall]

GLUE ALL JOINTS

With foaming floor glue.

 

[0Floz0]

GLUE ALL JOINTS

With foaming floor glue.

What about the eps? Would you glue those together or just pressure fit them?

 

[noseall]

What about the eps? Would you glue those together or just pressure fit them?

Tape the joints (foil tape).

 

[0Floz0]

Tape the joints (foil tape).

Even though there is no tape on the eps itself?

 

[noseall]

Even though there is no tape on the eps itself?

Sorry thought you were on about Celotex type. I stopped using polystyrene many years ago.

 

[0Floz0]

Sorry thought you were on about Celotex type. I stopped using polystyrene many years ago.

I was going to use celotex type originally but its less than half of the price to use EPS70. Given i've got 220mm I can get away with it. But there is very little info out there on how to construct it. Any time I put floating floor in I just get info on laminate floors.

 

[noseall]

Given i've got 220mm I can get away with it.

Two layers?
Make sure you bond the joints and that you avoid straight nick when you fit the deck.

 

[0Floz0]

Two layers?
Make sure you bond the joints and that you avoid straight nick when you fit the deck.

Was going to be 3 layers of 75mm which I’m slightly nervous of. What would you bond the joints with and what do you mean by straight nick?

 

[noseall]

Was going to be 3 layers of 75mm which I’m slightly nervous of. What would you bond the joints with and what do you mean by straight nick?

You don’t want any of the joints to clash. So when setting out the first layer, have the final layer of chipboard deck I’m mind. The obvious scenario would be to offset the long joints by say 300mm.
So if you had a 300mm cut along the wall directly below the deck, the long joints should never clash, as long as you start with a full 600mm sheet off the wall.

 

[0Floz0]

You don’t want any of the joints to clash. So when setting out the first layer, have the final layer of chipboard deck I’m mind. The obvious scenario would be to offset the long joints by say 300mm.
So if you had a 300mm cut along the wall directly below the deck, the long joints should never clash, as long as you start with a full 600mm sheet off the wall.

Ah ok, I see what you're saying. The plan was to alternate the laying pattern so no long joints sit on it. Its 2.1x4m so was planning to alternate layout of each of the layers. I just worry that having 3 layers may lead to some sort of bounce?

 

[noseall]

No idea about bounce. I’ve only used PIR boards and then it’s only been one layer. The chipboard at 22mm thick and glued, should be quite stiff. I’d just worry about any bow memory in the sheets