25mm or 50mm ufh edge insulation

Cushtie

hey folks,

very quick one. will be laying the insulation for the UFH on the ground floor this weekend. I am putting 75mm polyiso (xtratherm) over the subfloor but am wondering what should I put as the edging strip 25mm or 50mm.

also UFH company guy said I should also put the strips on the internal walls also. is this a bit of over kill. It is no hassle to do it when I am doing the rest but was just wondering.

any thoughts or ideas most welcome.

Cushtie

yop

Cushtie - We put 25mm on the external walls of ours only, have to tape the joints though.

But I presume the more you put on it the better, only thing is that your final floor will probab finish flush with the top of the strips so with 50mm of a strip you have a nice area exposed.

patrido

the edge insulation acts an an expansion joint on internal walls, around door frames etc.

if you're using a sand/cement screed (as opposed to an anhydrite one) there will be a lot of expansion and contraction, so to avoid cracks put it in. this is required by bs1264, it's not just your ufh company trying to sell you more edge insulation.

tribesman

The internal walls act as a thermal bridge down to the foundation so its important to insulate the screed from the internal walls to prevent heat-loss.

I used 25mm polyiso

iplogger1

Out of curiosity.

Say I engage a company such as warmfloor (Tyrone?) to supply and install a UFH system do their guys pour the screed mixture and install the edge insulation or is this undertaken by the concrete floor laying contractors ?
Sorry if this seems naive. I've seen Yops posts and maybe Yop bought
the UFH system and installed it himself. I'm not going the direct labour
root for obvious reasons (I am a complete hack when it comes to
building technology)

Guys. Have any of you used solid wood rather than semi solid wood
fllors in conjuction with geothermal/UFH system?

Slightly OT but...
Also. I saw somewhere someone was mentioning to avoid ash as a
solid or semi-solid wood possibly in the context of UFH systems.
I am very inexperienced about timber types, etc. Is this a red herring?
Any reasons to avoid ash ? We were advised by a wood lover who
mostly advocates solid wood to use ash in the hallway as it is a nice
bright wood which is also heavy wearing.

CJhaughey

I am installing solid pine 17mm over UFH.
I have been monitoring water content over the last few weeks and it is dropping all the time.
I will float the floor over polyethylene and foam as soon as the moisture drops to 9% or below.

iplogger1

HI CJ

Was your decision to go for pine influenced in any way by the UFH ?
All I know about pine is that it is an attractive wood with aesthetic
natural look (eg, nice knots,etc) and that it is softer say than
oak or beech, etc. Are there some timbers which just don't
make good candidates for use with UFH ?

Do you feel that say as long as any good quality solid wood flooring
is at 8-9% moisture level and has acclimatised that you can float
it without introducing too many thermal inefficiencies when used in
combo with UFH and very reduced risk or warpage,etc ?

CJhaughey

No my decision to go for the pine was influenced by price and the fact that it was able to be supplied by my builder as part of a kit when the whole house came.
I am not 100% about no warpage, my supplier says that he fitted the exact same boards in his house and encountered slight cupping which was sanded down.
The boards have flutes on the back to reduce the tendency to warp.
I would suspect that the heat in my UFH is low enough to cause few problems 15w/m2 and that if you fitted a ufh system powered by a small heatpump that you would be talking about a similar output.
I have come to the conclusion that may of the problems that UFH and wooden floors have is because of oil fired UFH and the resultant high temps on one side of the board.
This is where engineered wood will be better than solid as it is basically plywood with a nice finish, and the plies will all pull in different directions rather than solid wood trying to curl up.
My suppliers advice to me was to run the heating for as long as possible with the windows open to dry the floor and wood.
Open the shrink wrap and stack the planks with battens between them and acclimatise them.(some of my planks are about 4m long)
Check moisture content and when it is 9% or below start laying.
Lay with a layer of plastic below and jiffy foam.
I intend to white oil the floor and make people remove their shoes. Of course with UFH it is not unpleasant to have socks on.
Thermal inefficiency is hard to define, I don't want a hot floor, but I want a warm room.
It is my personal opinion that people like to have their floors too hot, as long as the room is warm the heat is being transferred efficiently.

patrido

iplogger1 wrote:

Out of curiosity.

Say I engage a company such as warmfloor (Tyrone?) to supply and install a UFH system do their guys pour the screed mixture and install the edge insulation or is this undertaken by the concrete floor laying contractors ?
Sorry if this seems naive. I've seen Yops posts and maybe Yop bought
the UFH system and installed it himself. I'm not going the direct labour
root for obvious reasons (I am a complete hack when it comes to
building technology)

Guys. Have any of you used solid wood rather than semi solid wood
fllors in conjuction with geothermal/UFH system?

Slightly OT but...
Also. I saw somewhere someone was mentioning to avoid ash as a
solid or semi-solid wood possibly in the context of UFH systems.
I am very inexperienced about timber types, etc. Is this a red herring?
Any reasons to avoid ash ? We were advised by a wood lover who
mostly advocates solid wood to use ash in the hallway as it is a nice
bright wood which is also heavy wearing.

the ufh company will not do the screeding, and may not do the insulation either. check beforehand (though all that detail is usually in the small print).

they will pressure test the system, and give you a written record of the pressure test, and once you sign off on that, their part is done. any damage or pressure drop after that point is not their responsibility.

i have not heard any bad things about ash in terms of ufh... it is quite hard wearing, and has a lower coefficient of expansion than oak, maple, beech, etc. it's always best to ask the floor supplier/manufacturer if their particular product is suitable, but i see no major reason why ash should not be.

patrido

CJhaughey wrote:

I would suspect that the heat in my UFH is low enough to cause few problems 15w/m2 and that if you fitted a ufh system powered by a small heatpump that you would be talking about a similar output.

15w/m2 is very very low output - are you sure you can heat the room with that low output? do you have another heat source like blown air? if it is correct, you should have no problems... it's only when you approach 90w/m2 that floor temp might become an issue.

CJhaughey wrote:

I have come to the conclusion that may of the problems that UFH and wooden floors have is because of oil fired UFH and the resultant high temps on one side of the board.

you might be misunderstanding how ufh works. regardless of the the boiler / heat pump temperature, the ufh loop water temp will not exceed 45-50 degrees. the high oil boiler temp (possibly 80 degrees) water is mixed with colder water to achieve the correct working temp.

CJhaughey wrote:

It is my personal opinion that people like to have their floors too hot, as long as the room is warm the heat is being transferred efficiently.

a properly designed system will not exceed 29 degrees floor temperature outside of bathrooms or peripheral zones. hot floors should only occur where it has been designed incorrectly, sush as where the heat loss in the room is too high, or the usable floor area is too low, so the output per m2 is too high, resulting in an excessive floor temp.

Cushtie

thanks for the replies folks. I ordered the 50mm anyway. better to put it in all the walls now than regretting it later.

CJhaughey

patrido wrote:

15w/m2 is very very low output - are you sure you can heat the room with that low output? do you have another heat source like blown air? if it is correct, you should have no problems... it's only when you approach 90w/m2 that floor temp might become an issue.

Sorry my calculations are a little wrong I have 2 electric loops 1 of 2.3kw and another of 2.6kw totalling 4.9kw
Floor area of 99m2=20w/m2
I also have a 6kw solid fuel stove installed and Heat recovery ventilation,Plus a large part of the south side is triple glazed low emission glass.
I hope it will be enough!!


You are correct on the other points re Floor temp.