Anyone fitted their own under floor heating?

[vivienne wykes]

Hi All, Has annyone fitted their own underfloor heating and if so would there be any tips / pitfalls to pass on.

Regards

Jim Ascroft

[IMM]

First of all get the "design" right. If this is screwed up it is difficult to reverse. Is this to be in anew house? If in an existing house, what type of floors do you have?

[vivienne wykes]

Hi thanks for that,

I am converting a barn in the Scottish Borders. It has poured concrete on th ground floor and joists on the first floor. When I do the heating it will be justr the joists no existing floorboards due to woodworm....

[The Natural Philosopher]

Yes.

and if so would there be

Read up and come back with questions.

There are other sites too.

[The Natural Philosopher]

Do you mean that you are NOT doing the ground floor? That is the logical place to do it.

Under-wood-floor is harder, more expesnive and has a few issues.

Still the best tho, but not cheap...

[vivienne wykes]

[IMM]

Make sure the ground floor is very well insulated. The insulation should be like a tray wit the side running up the wall to poured concrete level.

Put as much insulation in the bar as possible, and then size up the UFH from there. You may only require UFH on the ground floor, if insulated well enough.

[The Natural Philosopher]

So fra so go, but teh 'wit' bit as usual leaves one confused..IMM trying being witless.

Thats to keep the ice from melting in your gin and tonic of course.

Whatever that means. I am sure its really profound.

Oddly, I find that wrapping UFH in insulation reduces its effectiveness, but grammar, punctuation and the ability to understand or communicate the fabulous ideas IMM has read about in glossy brochures has never been 'our Johns' strong point.

However, yes, attempting to remove the babble and concentrate on the facts (although I assumed you would glean those from reading up) its best under concrete ground floors over as much insulation as you can stuff UNDER the FLOOR (not round the heating pipes!) in order to maximise the losses to the room (wanted) to the losses into the ground (wasted, unless breeding earthworms for profit or protein)

Unless you are largely open plan however, upstairs will need heating: The amount of 'superinsulation' Our John would have you install along with completely sealing each upper room hermetically is simply infeasible.

I chickened out on a similar project and installed hot air blowers upstairs fed from hot water. But on reflection it would have been not too hard to do UFH on the upper story. The big problem is stopping heat going down to the floor below, (extra insulation between floors) and making sure that the floor structure can stand the variation between high summer humidity, and very low winter humidity (when heated) without deformation. Chip flooring is fine if carpetetd, though teh insulatin ofte carpet underla is undesirable, laminate is excellent from a technical point of view, but you may hate it, tiles are good, but you need to be wary ogf real wood planks: These can easily warp and cup massively. Its not insoluble, but it needs consideration.

You do need to think about thermostats and control systems tho. If the house is massive in thermal inertia and well insulated the ground floor is probably OK on a simple 'on all night' or 'on all the time' basis with a single overall thermostat to control it - I have this, and it works very well.

However upstairs where the all timber construction is much faster to heat up and quicker to cool, I find that individual room controls plus an overall different timing is required. Therefore I have a three zone controller (UFH, Upstairs hot air, and Hot water) and stats on each upstairs room. Its also nice to be able to disable unoccupied spare rooms.

For wet UFH heating upstairs I think standard TRV's on the feed to each room are probably no worse that electrical stats and wires coming back to the manifold. However you do need to consider the case where all upstairs rooms are essentially 'shut down' but there is no overall thermostat to cut the pump.

I have solved that one in the past by allowing one room - usually a bathroom of small dimension, to run unregulated with a massive heat input. I like hot bathrooms. This at least gives the pump something less than a complete blocked circuit to pump.

Or if you have e.g. an unheated upper corridorr, you can put a master zone stat in that. Esssentiall teh zone stat should be where the heating outptout is lowest so is the last bit to warm up.

The really class job is to split the house into two zones for two separate timers, and one circuit per room, use electrical 'stats in each room feeding motorised valves on the manifold, with an overall wired OR circuit so that any stats that demands heat will set the pump going.

Since you need a separate pump also to run DHW, you tend to need a relay in the control wiring as well.

None of this is rocket science, but if you are condsidering a class system, make sure you run wires from a stat in each room back to your 'control center' and don't understimate the size of that - all my stuff is in a large cupbiardd in the boiler room where it can be got at, and there us a lot of pipework and wire in there too :D

If you want to enter into detailed discussion its probably best to take this offline to e-mail, as it gets tedious

[:::Jerry::::]

Teh, Teh Mr Philosopher ! If you're going to criticise typographical error on Usenet then please make sure that you don't do any yourself !

[IMM]

You need professional attention. Reading what you installed I would advise all not to take any notice whatsoever. It is clear you only have half a clue. That is sad.

[The Natural Philosopher]

John, take half an aspirin in some warm ovaltine and have a little lie down.

This is all way above your head.

[IMM]

Our resident snot is at it again. A total amateur who thinks he knows more than the pros. That is sad. Keep taking the tablets.

[:::Jerry::::]

IMM, who are you talking about here, yourself, Mr Philosopher or both (perish the thought that you both might be the alter-ego of the other ! [1]) ?

[1] they do both have a similar style of insults...

[xenelk]

Wow, the woodworm have eaten all the floorboards! They *were* hungry!

[Pet]

Another company I feel worthy of mention is Nu-Heat. Only because I used them. :¬) You give them all room dimensions and measurements, joist widths etc etc etc and they work out exactly what you need, how many loops and rows and coils etc and, if time is more of an issue than money, it makes sense (did for me anyway) to have someone sorting out that side of things to make sure it's right first time. (leaving me to do he stuff I'm good at which pays the bills)

I must say, Nu-heat have been incredibly good with regards to every single aspect of our project. I should have a photo diary of the project when complete...... whenever that may be.

[Rick Dipper]

I fitted mine, I fitted it from the undeside of a ground floor, went down into the voild and attached it to the bottom of the floorboards.

1) get a good device for nailing the clips up 2) clean out the voild first 3) don't use rockwool to insulate it. 4) don't use rockwool to insulate it. 5) don't use rockwool to insulate it.

Rick

[Rick Dipper]

I used nu-heat when the supplied kee-tripple-tube. The tubs has burst, my guarentee is useless.

Rick

[G&M]

Yep

Yep

Why not ? Worked for us just fine. Pinned a plastic sheet at one end across the joists then moved along, stuffing the Rockwool in and pinning it up straight away.