Wooden floor on UFH

voodoo

Hi all,

Please, Please help...

We have UFH installed and ready to be turned on in the next 2 weeks or so and finalising what floors to put on the Living and Sitting rooms. When we speak to our plumber, he said that he has semi-solid floors installed in his house for the last 5 yrs with no problem...

However, when we go to floor providers, we are getting mixed messages... some say we can only install semi-solid, others say it has to be solid and today, when picking tiles from a store and enquiring about their wooden floors, we were told it can only be engineered floors (not laminate)...

Can someone please put this to bed for us as it's annoying us both! Also, once the heating is on, should we bring in the wooden floors to the house to get them "accustomed" to the heat of the house before we put them down...

Thanks

CJhaughey

I will give you my experience with UFH and wooden floors.
I was also told that I couldn't use all the flooring you describe above.
However I have 20mm solid red deal down for the last 5 years and no issues at all with the UFH.
Now I would strongly advise the fitting of a plastic vapour barrier below the underlay on a concrete floor.
I have a friend with semi solid on UFH and he has also not had any problems with it or heat not entering the house.
Just make sure your floor has adequate clearance around the edge so that when it expands and contracts it can move and not bind.
Cork underlay is supposed to be very good for UFH, saying that I used the cheapest PE foam you can buy and it has been fine.

mr_edge_to_you

We put in UFH upstairs and downstairs.

We have walnut engineered floor in the sitting room, and tiles everywere else downstairs. The engineered floor is glued down. Fairly powerful stuff. Everyone we spoke to told us that engineered or semi-solid were the only natural timber options for floors with UFH.

Upstairs (and in a spare bedroom downstairs) we have laminate. We were advised to put down a vapour barrier and a rolled foam insulation layer under the laminate.

We bought all out flooring from a large Irish chain. The manager of the shop told us that in advance of putting down any floor coverings on UFH, you should turn on the heat and gradually increase the temperature over 4 or 5 days. Then leave it alone for 2 or 3 days and then switch it off. When the floor has completely cooled down then it is safe to start. He also came out to the house with a device to measure the moisture levels in the screed which is very important before we started flooring.

troyh

Im assuming the UFH is laid in a Screed above 100-120mm Insulation and has edge insulation around the perimeter of the room to finished screed level.

A few technical aspects to laying wooden flooring over UFH.
1. In general the surface temp below a wooden floor should not exceed 29 Degrees C and this MAX temp should be checked against the wooden to see if this limit is sufficient.
2. Hardwoods (Oak, Maple, etc) are a better choice over Soft Woods (Pine, red deal, etc) as the do not suppress heat as much.
3. The wider the boards the more suceptable to expension/shrinkage - best to stick to a board less than 70mm or so.
4. Moisture. Concrete screeds should be fully cured (must be verified using moisture tester) and the heating should be utilised for at least 1 week prior to laying floor. This will set up the temp and moisture levels to normal conditions. Overall the building moisture content should not be above 10% and I would leave the flooring packs (unopened) in the room for two weeks at least.
5. When laying turn off the heating and bring it back up to user levels over a few days.

In general I prefer engineerd flooring as it's sub-base is multi-cross layers of ply and should (in theory) shrink/expand the same in all directions (Except for the top layer) I also prefer to fix the floor to either a plywood base (not an ideal option for UFH) or 50x50 battens with the screed laid between these. Finally, for UFH I like to leave a wider gap at the perimeter of the room for expansion and use a wider skirting to cover this gap.

Hope all this helps.

voodoo

Hi guys,

Thanks for the feedback... Interesting about the "glueing" the floor... I would have thought it wouldnt react well to the heat...

With regards to the screed, yes it's on 100mm insulation with 20mm around each room. The screed itself is 80mm (including the UFH pipe).

We are thinking of Oak anyway so that should be fine. So it seems we need to go an with an enginered floor...