Effectiveness of Underfloor Heating with Wooden Flooring

I am in the process of building a house that has under floor heating run in conjunction with a geothermal heating system. I have chosen to go with under floor on both floors as I believe the geothermal will run more effectively.

However I have now been left with the dilemma of what floor covering! Carpet is out because I suffer from asthma, so I am left with the options of wooden flooring (solid or semi solid) or tiling.

My preference would be to tile the hall, utility, kitchen/diner, bathrooms and put wood everywhere else (lounge and bedrooms) However the person that is in charge of my job is old school and believes (very strongly!) that wood is a poor conductor of heat, so by using this as a floor covering am I defeating the purpose of having warm floors, as it will take too long to heat.

It is of his view that the whole house should be tiled so as to work the underfloor heating though a product that is a good conductor of heat, thus making it cheaper to run

I just have a real problem imagining what the lounge could possibly look like with a tiled floor - however about the bedrooms!!! In saying that though the under floor heating has cost a lot to install so I obviously want it to work as effectively and economically as possible.

Has anybody had any experience with this?

Moved from .

tiles are the way to go. i have it in some rooms downstairs and these are tiled . ive rads upstairs which i think is better as 1 you dont want to be paying for all day heat in bedrooms and 2 i find it hard to sleep if the bedroom is too warm

Hi ClodaghK,
I'm confused about the 'conductor of heat' points. My understanding (which may be wrong) is that wooden flooring may have an insulating effect which may make it not the best for UFH. However, I have seen a lot of opinions to suggest that wooden flooring can work fine with UFH, especially if the wood is not too think.
I have UFH all over new 2100 sq.ft bungalow and plan to use wood in lounge and bedrooms with tiles everywhere else. I don't think I could have tiles everywhere. Anyway, I plan to use semi-solid wood which is relatively thin (about 14mm I think) which I believe is more appropriate for UFH than thicker full-solid.

semi solid works cos as its plywood with alternate grains at 90 degrees so it wont warp. id say youd have to glue it direct to the cement, no foam

What does he mean by 'conductor of heat'? - How hard it is to heat up?

this page might be of interest;
http://en.wikipedia.org/wiki/Specific_heat_capacity

I believe your post should read "wood is a poor conductor of heat"?

I have done this (geothermal--> UFH --> part tiled/part wooden floor).

No problem with heating through the wood - it's a lovely soft heat on the foot. Heats the house effectively aswell.

As underfloor heating takes about a day and a half to heat up properly, the speed of conduction isn't really a problem (it just takes a couple of hours longer). If the UFH is properly insulated below it, the heat is only going to go up, even if it takes a little bit longer to get through the wood).

You probably won't want the geothermal on during the summer (except for hot water), in which case the tiles will be cold underfoot, so wooden floors are a must IMO.

My floor man would only put Junckers solid down on the UFH. Cost an arm and a leg. No problems with it after 20 months. Brooks have a sale every six months (should be one in September/October?) where one can usually find something half-price that one likes! There are other threads on other wooden floor products that may also work, but I have no experience of them.

The following page, by one manufacturer/supplier of underfloor heating, discusses the suitability of a range of floor coverings (there is a link for deails of each floor covering):

http://www.nu-heat.co.uk/s.nl/sc.7/category.18/.f

From that it looks like wooden or laminate floors should be fine as long as they are no thicker than the recommended max that they state. The same advice should apply regardless of whose underfloor heating system you use.

Good luck with it. I have friends whose house has geothermal underfloor heating and they are very happy with it (wooden flooring too, as far as I can recall).

We have wooden engineered wooden flooring on UFH aswell, and have had no problems. It's 14mm mdf backed, as opposed to the plywood backed type. The denser board is supposed to conduct heat better. It's click flooring, so it's easy to lay aswell.

The tiles been cold during the summer is a very good point, as the heating won't be on much during the summer.

Just a couple of related questions...

Is it best to glue engineered wooden flooring to floor and if so what type of adhesive should be used ?

For tiles, what type of adhesive/cement should be used when going over UFH ?

Thanks

ennisjim said:

Just a couple of related questions...

Is it best to glue engineered wooden flooring to floor and if so what type of adhesive should be used ?

For tiles, what type of adhesive/cement should be used when going over UFH ?

Thanks

Click to expand...

I believe that it is a bad idea to glue wooden flooring for UFH. As the heating will be off during the summer, the boards will expand, while they will contract in the winter due to the UFH. The contraction and expansion is not very much, but if the boards were glued, it could be enough to bow/split them.

Our tiler used standard floor tile cement. Just don't tile with the heating on, as it dries out too quickly was his advice.

Note: I am not a builder, so you may want to wait for more than anecdotal advice before proceeding!