Wet UFH and engineered wood

[mrpupsi]

Evening all,

I’m currently in the process of refurbing my house, and have opted to wet UFH for the whole of the downstairs.

The upstairs will be radiators.

The flooring I’ve chosen is 14mm thick engineered wood and I just wanted to know the best way to do things.

At current, the builder was going to use 20mm thick grooved panels for 16mm pipes, laid directly on the existing floorboards and existing concrete where the extension is.
His idea was to float the floor, but this doesn’t feel right under foot to me, and I’d prefer it to be glued.

Would we then screed directly on top of this with a 50mm layer, and when dry, glue the wood directly to this?
Would we need to lay a polythene sheet first, and then the panels, and then screed, in order to stop the screed pouring into the existing gaps?

Thanks in advance

 

[ShaunCorbs]

Any reason you can’t lay the pipes directly under the engineered floor ?

 

[mrpupsi]

In order to glue the floor down, I was under the impression that we cannot glue it directly to the panels, which I’m pretty sure are the same if not similar to EPS400 low profile panels

 

[IND_Nick]

We've just finished a 100sqm floor with the EPS400 low profile boards, they were glued and mechanically fixed to the floorboards below, then primed and screeded with a latex floor levelling compound (5mm ish) and finished with 12 mm glued engineered flooring.
Just made sure we had floor temp thermostats installed so wood doesn't get too hot.
Final floor looks great and is solid. Materials bought from Eddie @ Uheat who I believe sponser this forum.

 

[mrpupsi]

Cheers mate, that sounds pretty much like what we want to do.

Can you spread more light on the prep work you did laying the boards and screeding?
Just generally the whole process if you don’t mind, in a bit more detail.

Thanks

 

[IND_Nick]

Not much more detail I can offer really, we only installed the panels and run pipe. Screed and finish floor left to the flooring company, but they were happy with our bit. I've attached a photo of what we left.
The panels are light weight but have high compression values, we glued these down with supplied spray adhesive to the floorboards below. Then screwed the corners, middle length with large washers as a secondary method.
As above if you contact the UFH materials supplier they are normally very good at explaining methods and products to cover whatever you want to achieve.

 

[mrpupsi]

Appreciate it mate, was just curious if a polythene sheet had to be laid on top of that, and then screed on top, to stop it leaking out down the sides of the walls.

I’ll give UHeat a call, thanks again.

 

[IND_Nick]

Appreciate it mate, was just curious if a polythene sheet had to be laid on top of that, and then screed on top, to stop it leaking out down the sides of the walls.

I’ll give UHeat a call, thanks again.

No sheets, they used a small bead of foam all around the perimeter to keep the liquid screed in. They also primed the boards with a slightly gritty finish I assume so the liquid screed adhered to it. Fortunately it was quite a level floor to begin with so it was just a thin layer, to cover joints and any small undulations.