Fixing semi-solid floor on top of ufh and screed

dcom

Hi,

Just a quick question about fixing a semi solid wooden floor.

We are putting in underfloor heating with some semi-solid wooden floors over the screed.

The options available for installation as recommended by the floor company are
1. Gluing the floor direct to the screed using a special glue
2. Fixing it using secret nails which I assume are nailed to wooden battens.

My question is: if the battens are laid on top of the screed will that not leave an airgap between the wood and the screed. and an airgap will negatively affect the performance of the ufh?

Would it be better to place the battens on the sub floor then pour the screed around them or sink them into the screed, so that the floor can be fixed to the battens and sit directly on top of the screed??

RKQ

Semi-solid timber is usually floated over underfloor heating slab. Secret nailing carries the risk of puncturing the pipes.

Solid timber floors can be glued to the slab. The primer and glue can be quite expensive.

dcom

Thanks RKQ.

I thought a floating floor, semi-solid or not, would leave an airgap between the screed and the timber and this would adversely affect the performance of the ufh?

RKQ

dcom wrote: »

Thanks RKQ.

I thought a floating floor, semi-solid or not, would leave an airgap between the screed and the timber and this would adversely affect the performance of the ufh?

This is true to a certain extent but hot air rises, so its not a problem.

Solid timber on battens would leave a larger gap.

I have oak semi-solid on my ufh and it works fine. I'd say the porcelain tiles are better as they hold the heat and are certainly warm to the touch but semi-solid is fine.

gummibear

Hi guys, just checking because i laying semi-solid in lounge and laminates in bed-rooms on UFH. so by floating you are saying the boards are not glued or nailed to floor? What kind of underlay should i use if any? Cheers

dcom

Thanks RKQ.
Gummibear, Im really only a novice but as far as I know a floating floor is one which is not fixed to the sub floor whether that is nailed to the battens or glued to the sub floor directly.
Basically a floating floor is all glued together and left 'floating' on top of the sub floor.

Im not sure about the underlay some of the floor suppliers were advising us to buy underlay others were not so hopefully somebody can advise you on whats the best for your floors.

Good luck with it.
D

RKQ

Floating the floor simply means putting the boards down on the slab - they "float" over the slab. A gap is left at the perimeter for expansion & contraction - which is extremely important.

The boards are not fixed in any way to the slab. The semi-solid t&g boards are glued to each other along all grooves. Some manufacturers "clip" the boards together with metal clips.

The main job of the underlay is to take the bounce / vibration out of the weight of your foot as you walk etc. It helps slightly to provide a level surface to lay the boards on.

There are special underlays for UFH but I remain to be convinced. Heat rises so standard underlay is probably fine.

Underlay also provides some sound insulation. I'd recommend it under semi-solid and laminate flooring.