Hardwood flooring and Underfloor Heating: advise needed.

PH01

Got this detail for hardwood flooring and underfloor heating for my house.
I'm kinda nervous about it though - not sure about the way the battens go all the way to the concrete - doesn't that defeat the purpose of the insulation?

daveg

According to your diagram you have (from top to bottom):

Hardwood flooring - screed and heating - Kingspan insulation - conrete. In other words the heating lies between the flooring and concrete so the heat must escape upwards (correct?).

PH01

Yes that's pretty much it. It's a ground floor layout so I suppose it should be OK shouldn't it?

Victor

Timber is a relatively good insulator, so no particular need to worry. You also have a few thousand kilometres of rock below to act as an insulator. It needs to go all the way to the concrete to ensure adequate support, battens on insulation wouldn’t do this.

Make sure you follow the advice about drying out the floor and the acclimatising the floorboards properly - otherwise you are like to get shrinkage and / or warping.

Borzoi

It strikes me that 15mm hardwood is very thin if it's only batten supported. What's the distance between the battens?

The other thing that that I notice is that you will effectively loose 90mm of ceiling height. Will this be okay? Is this a new house pre build or is this existing and will you end up with 25mm of skirting left.

Like yourself PH01, I'm looking at the whole package and thinking hmmm, the main worry I have is that the floor is going to be more prone to warping because it's close to a heat source. I'd want to see examples of the style of installation, talk to people who have it a few years etc. Are the same people supplying and fitting for you? Is it a complete package? ie heating and timber floor.

As Victor say, the battens, being of wood will not conduct heat through to your concrete sub floor, that's not an issue:)

PH01

Originally posted by Borzoi
It strikes me that 15mm hardwood is very thin if it's only batten supported. What's the distance between the battens?

The other thing that that I notice is that you will effectively loose 90mm of ceiling height. Will this be okay? Is this a new house pre build or is this existing and will you end up with 25mm of skirting left.

Like yourself PH01, I'm looking at the whole package and thinking hmmm, the main worry I have is that the floor is going to be more prone to warping because it's close to a heat source. I'd want to see examples of the style of installation, talk to people who have it a few years etc. Are the same people supplying and fitting for you? Is it a complete package? ie heating and timber floor.

As Victor say, the battens, being of wood will not conduct heat through to your concrete sub floor, that's not an issue:)

Great to know that I don't have to worry about the battens - cheers lads. And I got the center of the earth to play with which is comforting

On the ceiling height, I don't think I'll have to worry as I got plenty of room to play with - about 2800mm.

On the supply and fitter, I haven't contracted anyone yet but I have talked to VFM in Castlebar and they seem pretty much up on underfloor heating and solid wood floors. They talked about acclimatising the timber and all that in the preheated house for a couple of weeks or was it 10 days. And the moisture content of the room has to be right as well.

And they said that they could glue the floor down rather than nail it down. Seemed a strange concept to me but I'm willing to give it a go. Yourman at the shop said that this would give the floor a better contact with the heated surface below - better for the transfer of heat, so he says. Sound convincing doesn't it?
If so wouldn't I be better removing the battons altogether as i won't need nails to pin the floor down?

Also, the flooring that VFM supplys is 19-22mm and not 15mm. They say there is more 'life' in the thicker board and better to work with. But with 15mm the heat conducts better.

Getting all confused now.

Borzoi

Originally posted by PH01

On the ceiling height, I don't think I'll have to worry as I got plenty of room to play with - about 2800m

ok, good in fact.

On the supply and fitter, I haven't contracted anyone yet but I have talked to VFM in Castlebar and they seem pretty much up on underfloor heating and solid wood floors. They talked about acclimatising the timber and all that in the preheated house for a couple of weeks or was it 10 days. And the moisture content of the room has to be right as well.

This has to be done for all solid on semi solid floors, but yours especially as it will be by the heat source

And they said that they could glue the floor down rather than nail it down. Seemed a strange concept to me but I'm willing to give it a go. Yourman at the shop said that this would give the floor a better contact with the heated surface below - better for the transfer of heat, so he says. Sound convincing doesn't it?
If so wouldn't I be better removing the battons altogether as i won't need nails to pin the floor down?

This sounded dodge to me, not nailing a solid hardwood floor, I'd never heard of it before, so I took a look at the VFM site:

'floating' the floor which means laying the floor on an underlay and glueing the joints with woodglue. Like glueing to the concrete floor, this minimises the height problem. Whilst many people have installed floors like this with no problems, VFM do not recommend it as a method of fitting, particularly where the floor area exceeds 20 Yd2 (17 M2)

Maybe you need to speak to them again...

Also, the flooring that VFM supplys is 19-22mm and not 15mm. They say there is more 'life' in the thicker board and better to work with. But with 15mm the heat conducts better.?

I suppose it is a trade off between heat conductivity, and floor strength, but personaly I'd go with the thicker plank

Getting all confused now.

I bet I haven't helped that:D , but I'm drawing on my own experience in putting down laminates, semi and solid floors, and the research I did into them.

PH01

Glueing sound dodge alright but the way they described it to me is that there is no underlay involved and the planks are glued directly to the concreate - kinda like the way you lay floor tiles.
It's suppose to be a special type of glue - one that conducts heat efficiently.
Sounds pretty technical doesn't it?

Borzoi

sounds iffy:D

what doo the guuys who make the underfloor heating say>?

Victor

Originally posted by Borzoi
It strikes me that 15mm hardwood is very thin if it's only batten supported. What's the distance between the battens?

Yes it does depend on distance between battens, but it is also part supported by the screed over the heating pipes. The thinker the boards the greater the insulation factor from them (which you don't want).

Originally posted by Borzoi
The other thing that that I notice is that you will effectively loose 90mm of ceiling height. Will this be okay? Is this a new house pre build or is this existing and will you end up with 25mm of skirting left.

Not a huge loss, but you may need to refit the skirting boards and adjust the bottoms of doors. You also gain floor space by not having radiators.

Originally posted by Borzoi
Like yourself PH01, I'm looking at the whole package and thinking hmmm, the main worry I have is that the floor is going to be more prone to warping because it's close to a heat source.

Not a real problem - the surface temperature of under floor heating is something like 26 degrees C. The lower temperature reduces the chances of burns to young children, the elderly, etc. It also means mopped floors dry quicker.

Originally posted by Borzoi
I'd want to see examples of the style of installation, talk to people who have it a few years etc. Are the same people supplying and fitting for you? Is it a complete package? ie heating and timber floor.

This would be an ideal situation, but get some sort of manufacturers guarantee for 3-5 years.

Originally posted by PH01
And they said that they could glue the floor down rather than nail it down. Seemed a strange concept to me but I'm willing to give it a go. Yourman at the shop said that this would give the floor a better contact with the heated surface below - better for the transfer of heat, so he says. Sound convincing doesn't it? If so wouldn't I be better removing the battons altogether as i won't need nails to pin the floor down?

My personal preference would be to do secret nailing (i.e. each nail is hidden by the next board) anyway, but leave it to their manufacturers instructions and demand that guarantee.

Originally posted by PH01
Also, the flooring that VFM supplys is 19-22mm and not 15mm. They say there is more 'life' in the thicker board and better to work with. But with 15mm the heat conducts better..

Yes the board will last longer, but how much more expensive is it? Is it the same species? The life / thickness of the board is important if you want to sand down the boards in a few years time.

'floating' the floor which means laying the floor on an underlay and glueing the joints with woodglue. Like glueing to the concrete floor, this minimises the height problem. Whilst many people have installed floors like this with no problems, VFM do not recommend it as a method of fitting, particularly where the floor area exceeds 20 Yd2 (17 M2)

17 M2 would be the size of an average to small bedroom, so I can imagine "stretch marks" and bumps arising in long rooms, especially corridors.

PH01

Rang up VFM again and asked again about the glue and the thickness of the planks.

They don't have solid wood flooring around the 15mm, but they do stoch semi-solids at that thickness. I don't really want semi-solids - won't wear as long as solids. So it looks like I'll have to with the 19mm to 22mm boards.

And on that glue, it's Sika Bond - says it can be used with underfloor heating.

And from Wooden Floor Services they say

Gluing:Used with solid floors, the timber is glued directly onto the existing floor using Sikabond T2. The T2 gives a totally naturtal feel. The adhesive is applied with a glue gun and provides a batton effect. Once cured T2 is fully elastic which allows for differential movement between bonded surfaces. This gives a less rigid and more natural feel, which is favoured by most of our customers and fitters alike.

Borzoi

Ah right, so we're talking a bit more than your standard PVA job.

Seems like a goer so

Milkman

hmmmm...
We did quite a bit of research on underfloor heating , for both tiles and timber floors, decided not to go with it in the end, as it wasn't right for our house.

But, I'm very surprised that companies are recommending glue for solid timber, or nails for solid timber. Solid timber will contract and relax slightly during the year, hence squeeky floor boards in houses some of the time. It is normally recommended to fix floor boards with screws, as these hold the boards in position much more reliably over time...
Sorry to throw a fly in the ointment, but its what I would use.

M.

Victor

It depends on the nail - floor brads would tend not to move much. Likewise with secret nailing, the nail has nowhere to go to be loose.

Capt'n Midnight

On one of Duncan's programs a while back I saw a device for central heating - it was a heat exchanger.

The idea is that when you turn on the heat, instead of hot water going into the pipes straight away you heat up the colder water first. - This would mean there is no sudden temperature increase under the floor - might help with warping - no idea if it was for wood or not.

Are you looking at real wood / laminate or the 4mm stuff ?

There must be a market or product there for 4mm wood on a conductive backing - best of both worlds.

PH01

Originally posted by Borzoi
Ah right, so we're talking a bit more than your standard PVA job.

Seems like a goer so

PVA?

PH01

Originally posted by Victor
It depends on the nail - floor brads would tend not to move much. Likewise with secret nailing, the nail has nowhere to go to be loose.

Going to be going with either the glue or the nails, and the 20mm Oak wide board.
And the nailing would be secret nailing - ie the nailing that can't be seen where it is nailed diagonally at the joins. I think?

Another thing that concerns me is how 'level' the floor will be before we nail/glue down the planks as I want to avoid air gaps. I'm afraid that with the battons that it will take quite a bit of skill to get the floor level without bumps and stuff. Where with a contrete floor you've a better chance of getting things flat and level.
Or am I worring about nothing here?

Borzoi

Originally posted by PH01
PVA?

General purpose wood glue. Probably stands for Poly Vinyl Adhesive, but I could just be making that up.

As for level, if you star level, it will continue that way. And i've seen concrete floors that are not level to begin with:(

Victor

Originally posted by PH01
Another thing that concerns me is how 'level' the floor will be before we nail/glue down the planks as I want to avoid air gaps. I'm afraid that with the battons that it will take quite a bit of skill to get the floor level without bumps and stuff. Where with a contrete floor you've a better chance of getting things flat and level.

Leave it to the professionals. Ask them are the happy the existing floor is level enough.

PH01

Originally posted by Victor
Leave it to the professionals. Ask them are the happy the existing floor is level enough.

Good point.

I'll ask them if they're happy with the levels considering that any 'bumps' will result in air gaps

Borzoi

The current issue of Building Services News has a 15 page spread on various methods and suppliers of underfloor heating.

Might be worth getting from your loacl supplier of HVAC material.

PH01

Is that "Irish Building Services News" magazine?

Where could I get it?

Tobi2

Hi PHO1 and all
Was doing a search for ufh and timber flooring and this thread came up.
Just wondering what you did in the end and how it worked out?
Am v.confused again re timber and ufh, for upstairs and what is best option?

Would really appreciate any advice or info from your personal experience.

Thanks so much in advance.

Tobi

unplug

I got underfloor heating installed 6 years ago and its been hardship it has never worked, The electrican blamed it on the plumber and visa versa the builder wasent any help and when I contacted the supplier of the heating system he told me my builder never paid him even though I gave my builder every last cent of my morgage.I was a young single girl 25 to be exact and trusted my builder who is a neighbour.(big mistake) Thankfully the supplier of the underfloor heating helped me he sent out an engineer who worked 2 full days on rewireing all the valves.my heating system is still not right and my house is always cold.Unfortunally I dont have any more money to spend on this.I have gone through hell the last 5 years so re think before getting underfloor heating installed.ID hate for anyone to go through what I had to.

Tigger

unplug wrote: »

I got underfloor heating installed 6 years ago and its been hardship it has never worked, The electrican blamed it on the plumber and visa versa the builder wasent any help and when I contacted the supplier of the heating system he told me my builder never paid him even though I gave my builder every last cent of my morgage.I was a young single girl 25 to be exact and trusted my builder who is a neighbour.(big mistake) Thankfully the supplier of the underfloor heating helped me he sent out an engineer who worked 2 full days on rewireing all the valves.my heating system is still not right and my house is always cold.Unfortunally I dont have any more money to spend on this.I have gone through hell the last 5 years so re think before getting underfloor heating installed.ID hate for anyone to go through what I had to.

since this has been resurected...

underfloorheting is not a good idea for ireland

our climate and habits suit rads

its a fad and will be gone soon spend yer money on renuable resuurse haeting sustems( rape oil burner and rads) and insulation

RKQ

Underfloor is great! Consistant heat all over the house.
We have it and are very happy with it.

We have semi-solid oak floor in our open plan living / dining area.
It works fine with underfloor.

We have porcleain tiles everywhere else - which are better IMO. Tiles are ideal for underfloor.

If you and your partner work from home, have young kids at home, then its great - toasty all day without the dry air of rads.

If you work away from home and nobody is at home during the day - then get rads!

bkbyrne

Guys,

Sorry if I'm hijacking this post but really need some advice on my undefloor heating system. When the stats on the walls kick out (IE rooms have reached their desired temperatures) the pump continues to run (Is set on a timer clock), also hot water continues to come in from the boiler........once the stats are satisfied should the pump turn off and outside boiler shut down? At the moment the only way i can turn off the boiler is at the fuse box! I feel that I'm burning oil uneccesarily?

any advice would be great