Underfloor heating

[Phoenix]

Would appreciate some advice from those who get involved in this, as it is not something I've had any dealings with other than providing supplies. But I am planning on putting electric underfloor heating in my new conservatory. Not intending it to be the primary source of heating, just to take the chill off the tiles.

1) How important is insulated backer board, considering there is 100mm of king span in the floor slab, would I be looking at unacceptably long warm up times if I omitted it? The reason I ask if the floor has to fit under a step. Laying the tile directly upon the floor slab I measure a 10mm gap, which has to cover the heating element, adhesive and any insulation. It sounds like 6mm of insulation would not leave enough for the rest?

2) I have seen on here that many recommend feeding the floor probe into a piece of 15mm HEP20 pipe to enable removal, Obviously to fit this under the heating the slab is going to have to be chopped out a bit especially to accomodate the bend radius. So this would put the probe halfway between the floor and the stab (which isn't heated due to the insulation) This doesn't result in inaccurate control?. Also, The probe does not need to be bedded in the adhesive to acheive thermal contact with the floor I guess?

3) What power level would one recommend. 150W/M² or 100, or 200?

Sorry for the 101 type questions, never laid the matting myself before :Blushing

 

[steptoe]

Deffo put the probe in a bit of 16mm copex, or similar,

Screed over the UFH before adhesive, use a plastic trowel.

Power depends on floor size and how fast you want it to recover,

 

[NozSpark]

Deffo put the probe in a bit of 16mm copex, or similar,

Screed over the UFH before adhesive, use a plastic trowel.

Power depends on floor size and how fast you want it to recover,

+1

If you have no room for backer board then you can't fit it,,, but you will have a larger thermal mass to heat up

 

[Phoenix]

Cheers Gents,

Looks like its just going to heating element screeded over and then tiles. If it takes too long to heat up I'll just not use it that often and the missus will have cold feet

 

[Murdoch]

Deffo put the probe in a bit of 16mm copex, or similar,

Screed over the UFH before adhesive, use a plastic trowel.

Power depends on floor size and how fast you want it to recover,

which means?

 

[OnOff]

You'd maybe better to get over to www.buildhub.org.uk (the resurrected eBuild) and ask over there about all things UFH. I did. My probe is in an off cut of the 16mm Pex-Al-Pex. I just crimped the end flat. Brought it up into what's going to be a "riser" by the door:







You'll get more info than you'll ever need on buildhub and no doubt be told 100mm PIR isn't really thick enough!

 

[steptoe]

which means?

How fast you need it to heat from cold,

 

[Murdoch]

How fast you need it to heat from cold,

To what temperature? from what temperature?

 

[steptoe]

To what temperature? from what temperature?

Exactly,

If you only want a couple if degrees in 2 hours then a low W will be fine,

If you want 10degrees in an hour then it needs to be a LOT more W

 

[Murdoch]

Exactly,

If you only want a couple if degrees in 2 hours then a low W will be fine,

If you want 10degrees in an hour then it needs to be a LOT more W

Sounds like a recipe for a moaning client....

 

[Phoenix]

I went for the 150w/ m² mat in the end, after all I just want to take the chill off the tiles and am not trying to cook them or heat the room!

The bad news is, that APC have lost it. Was supposed to be delivered today, so sign of it, so phoned them they checked with driver and says its been signed for by (name that isn't mine) by a bloke who was working in the garden and then went round the back of the house. I pointed out that my fences are such that clearly is impossible and only the missus has been in all day. They phoned the driver again who now reckons they have taken it to the same address in the next village (The road is an  A road that runs through many villages and keeps the same name)

No one is in, but have pushed a note with my phone number on. He cannot go far, when I nosed around the back to see if he was there, garage door was open... so guess he must have gone to one of the pubs

If no joy APC morning shift are going to ring me tommorrow and they are going to try and send a driver out to work out where the first one took the parcel!

Bloody muppets

 

[Sharpend]

I've always said heat mats are more trouble than they're worth!!

 

[steptoe]

Sounds like a recipe for a moaning client....

How come,?

Spec the job properly and everyone is happy,

I'm only trying to help the OP,

You just seem to be fishing for a fight,

How do you spec your ufh W then,? 

 

[pewter]

alot of the heat matt manufacturers are happy to specify what you need, and be quite helpfully.