Underfloor heating...... upstairs

[Pet]

Don't laugh. Just wondering if it's possible to put underfloor heating upstairs in place of rads.

Our house is upsideown, so living area, kitchen etc are top level with floorboards.

The large living room has a large patio door (to a balcony) and 2 large windows. When the night goes off cold, we have to sit with feet on sofa as the cold air seems to collect above the carpet. Radiators keep the room warm, but don't heat the floor bit. (cold not caused by draughts)

We also want to do lots of internal modifications, knocking out an archway on the end wall where one of the 2 big rad's are.

Any other ideas? Seen those big spirally type radiators which could sit in the corners, but don't know if they'd be up to the job in hand.

[The Natural Philosopher]

Yes.

UF is definitely possible, but it aint cheap under wood floors.

see

for some of teh techniques and so on.

They are basically laying pipes over foil backed poly insulation between the joists, which will need notching of course here and there.

I chickened out and put wall mounted hot aor blower in, but underfloor would have been even better. If I had has a void to put it in...

If its only a chip floor now, wouldn't cost too much to lift it. Nice floorboards thouh? Could get damaged.

Also remember to run the water at even lower temps than under screed, to avoid warps. Again polyplumb do a kit of manifolds and temp reduction valves and pump etc.

To connect the whole lot to an existing circuit you need top create a zone and attach the pump, temp reducer, manifold and its UF pipes to existing system, add a zone stat, and a relay to fire up the main CH pump when your secondary pump is running (but not vice versa: Hence the relay)

Its only warm water running under the floorboards, not rocket science, but the insulation is a must to stop half the heat leaking downwards. I am not at all sure the foil really does anything tho.

If I were to do it here, I think I'd lift the floors, plan the layout, put celotext down and just flop the pipe in between joists in big loops. Maybe tie wrap it here and there to stop it moving. Laying in teh premade stuff looks to fussy and expensive

[Christian McArdle]

Yes, it is possible. Not particularly cheap, mind.

Christian.

[IMM]

If the bedrooms are below I can't see why its so cold on the floors. Heat may be running under the doors and dropping down the stairs.

If there is a loft above the top floor, consider installaing a small Johnson Starley forced air with ventilation unit. This can have all the supply and return air ductwrok in the loft and grills opened up on the ceilings below. You could have a large grill in the hallway ceiling to heat the rooms below. Bedrooms don't have to be that hot. No rads on walls and fresh air too. All you need do is get a gas pipe to the loft, take the balanced flue ut via a gable end wall, or through the roof via a roof tile. Check it out. J&S have small units just for this application. Ring them, they are in Northampton.

a small unit. another.. We also want to do lots of internal modifications, knocking out an

[Christian McArdle]

I wonder if the underfloor area is ventilated with airbricks, like a ground floor normally is? This could lead to unusual coldness from the floor, even with heated rooms below.

Christian.

[Owain]

"Pet" wrote | Don't laugh. | Just wondering if it's possible to put underfloor heating upstairs | in place of rads. | Our house is upsideown, so living area, kitchen etc are top level | with floorboards. | The large living room has a large patio door (to a balcony) and 2 large | windows. When the night goes off cold, we have to sit with feet on sofa | as the cold air seems to collect above the carpet.

This is probably due to draughts - try draughtproofing the patio door and windows and using door sausages.

| Any other ideas?

Furry lined rigger boots?

Owain

[The Natural Philosopher]

Mmm. Beneifits of Nu Laber education. By a process of spin, heat now sinks, instead of rising.

Amazing!

[IMM]

Exactly, amazing what the snotty uni's teach them. The cooler air in the room, which still maybe warm to a human, drops to the floor, it may also drop down the stairs too. Duh!

I suspect that cooler air, cooled by the large windows is running along the floor. Replacing the windows/doors with triple glazed low "e" and sealing them up may help. UFH will help as will a forced air vent system. I would seal up any air leakages in the room/s and assess a forced air vent unit in the loft. All the work will be in the loft and no disruption to the house below, aprt from a pipe being run up there.

[Pet]

Nope. definately not draughts. You could get the man from Everest in there and his feather would fall straight as a die. Even when blowing a hoolie straight on to the doors/windows, no draught is evidednt.

too noisy. Being a topsy turvey house, upstairs "downstairs" noise is very loud in the downstairs "upstairs" bedrooms.

I was thinking UFH might help dampen some of the noise that goes into the bedrooms. (What with Insulation and stuff)

[Pet]

got a UFH pack on it's way to me.

Nope it's crappy chip board flooring.... at the moment. I'm already going to replace one of the rooms with floorboards where it has big bodged access "craters" you can fall through, (though the lounge floor is sound)

Looks like the polyplumb folks do a unit that enables connection to existing system, that might be handy.

I'm hoping insulation will also help dampen the sound that echoes through the downstairs bedrooms

Hmm..... I'll see what the postman brings. Don't fance the forced air idea as suggested, even warm "blown" air feels cold.

[IMM]

Buy the slabs for thermal insulation under the floor. Use a 25kg/m3 high density mineral wool roll or rigid batt that fits properly, filling the depth of the cavity without compression.

Dedicated acoustic felts cost and arm and a leg and yet don't perform much better than good mineral wools.

Try:

them to send you their product details and dealers.

Wickes sell batts, but I'm not sure what the density is.

[The Natural Philosopher]

Yes. I did all mine from scracth, but tapping in to an existing system would not be hard.

The biggest headache was building a control and wiring box, and sourcing a relay. Which IS needed with a two pump etup as I said.

Dream on...one thing that half worked for me was re-layng teh chipboard on a bed of inuslation board - the soft fiber stuff. However you would have to strip-lay that over the joists so as not to impede the warmth.

Laying carpet and foam underlay is also good, but its yet another barrier toi warmth ins't it? This needing MORE UF temp to get heating effect, and MORE UF insulation to stoop it heating downstairs ceiling.

Back to sq 1

It does work, but its not as nice as UF. A lot depends on wall insulation. The beauty of UF is there is very little temperature gradient. The coldets part (floor) is warmed, and becomes the warmets part. Yo can even get temperature inversions :-) If you have draights and cold windows, you need to add extra heat to make areas near there acceptably warm. But its hard to GET cold spots with UF. That has been my overriding impression. You don't even notice the room IS warm. You just don't feel cold.

Polyplumb is good value on pipes manifolds and pumps, but not the little

plastic pipe trays - however if you want to do the job fast,

there is no doubt it works very well indeed.

[Rick Dipper]

The brocure say you can, but I would never again put UF under a planked floor, it dires it out and the boards warp, maybe it was my floor, but thays my experience. I guess I could swop the boards for chipboard .............

Rick

[IMM]

Gledhill do not recommend Ployplumb, and specifically state their name, for connection to many of their appliances.

[The Natural Philosopher]

it dires it out and the boards warp, maybe it was my floor, but thays my

It is a big risk certainly. Especially with new boards of uncertain humidity content.

If you get quarter grain boards - don't look so good sadly - and stack em in the room for a year, and then lay em :-)

Even the all-wood laminated flooring I have had enough humidity absorption to swell up badly in one place over the summer - its supposed to be fully floating but bits of wall got in the way of expansion - though since the heating came back on its almost back where it started.

If you lay a fully floating floor of something like Kahrs laminateed wood, it works. Boards nailed down? BAD trouble.

[John Stumbles]

...

Agreed, generally: I UFHed my kitchen floor with Rockwool insulation supended on garden netting laid between the joists, 50 metres of 15mm Hep2O laid in loops clipped to Screwfix 'builders band' fixed atop the joists and plywood on top and tiles on that. The room generally feels comfortable - not warm, not cold - but in bare feet there are noticeable warm and cold patches: generally colder over the joists but also over some areas where there should be pipework directly underneath. I'd expected the heat to spread more evenly, especialy with the tiles on top, and wonder if it would have helped to lay tinfoil over the pipes or between layers of the plywood.

Incidentally the heating loop is just connected across the flow and return of the downstairs heating circuit (one end fed from a TRV in the underfloor space, to turn it off if it's generally warmish there anyway - but not sensing the output of the UFH). I had expected to have to balance it against the other downstairs rads but it seems to be in quite good balance anyway - the UFH loop gets warm, and so do the rads.

-- John Stumbles

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-+ Pessimists are never disappointed

[Grimly Curmudgeon]

it dires it

The first use of the UF heating should be at a minimal temp (somewhere under 10deg C) for at least a fortnight to allow the floorboards to acclimatise.

[The Natural Philosopher]

NOT very kosher as you OUGHT to have temp reducing system, but under chip should get away with it. Apparently screed will crack if overheated...

But bears out many anecdotal storues I have heard 'just put insulation underneath, run some pipe on top, and floor on top of that and its OK'

[The Natural Philosopher]

it dires it

More like 6 months. AND when it goes off in summer, out they swell again...