Anyone have underfloor heating under wood?

[swee'pea99]

We've been told we need 'engineered wood' or it'll all gnarl up horribly, but I'm still a bit baffled as to how the heat from the underfloor actually gets to be above the floor (where you need it), what with 20mm of wood in the way - wood being a pretty good heat insulator and all. Has anyone done this? Does it work?

 

[srw]

We've got engineered wood (essentially expensive laminate) above a hot-water underfloor system, and it works quite nicely. The general idea of underfloor heating seems to be that the flooring acts as a big storage heater - the floor "feels" warm.

 

[threebikesmcginty]

My next-door neighbours have electric underfloor heating under engineered wood - works well and they're very pleased with it.

 

[swee'pea99]

Thanks for that. Any thoughts on thickness? I'd been thinking of going quite thick - 22mm or so - because I'd like the floor to feel solid. I hate it when floors flex under your feet. But again, I'm concerned that that might put too much insulation between the heat source and my missus's tootsies.

 

[Ajay]

Engineered wood will be more practical than "real" wood, if using real wood make sure it's kiln dried or even reclaimed as it will be far less likely to move/warp with temp/humidity fluctuations.
Yes, wood is a good insulator and therefore would not be as efficient over UFH than say, ceramic tiles. The thicker you go with the wood the less efficient the system will be, maybe causing you to run the system at a higher temp, which would be more costly and also increase the risk of warping. Also, if you're adding a layer of sound insulation under the wood you'll also be increasing the TOG value of the floor, again increasing the workload of the UFH.
As SRW says, UFH acts more like a storage heater than a radiator, and isn't good for quickly heating a room.

 

[srw]

We were basically told (architect, so no real vested interest) not to even think about solid wood, even though it would be more expensive. The engineered board is tongue & grooved, about 20mm thick, and looks damned good. The top layer of wood is somewhere around 5mm thick - apparently it's thick enough to withstand two or three sand & reseals - so probably somewhere in the region of 30 years.

 

[swee'pea99]

Thanks for that. Do you happen to know if you need a bigger boiler? We're taking out three radiators (two full size, one small) and putting in about 20sqm of underfloor heating. Will the boiler be working harder, or less hard? (I've been trying to google for an answer to this basic question, but getting nowhere fast.)

 

[threebikesmcginty]

I'm interested in this as we're putting underfloor heating under engineered timber in some groundfloor areas and under solid boarding in 1 firstfloor room. Is hot water better than electric?

 

[Fnaar]

I just strap hot water bottles to my feet for that 'underfloor heating' effect. Also, it makes me wobble, like I've had too much to drink, so I save money there, too

 

[swee'pea99]

And there was me popping in to see Fnaar's words of wisdom. You'd think I'd know by now...

Re water v electric - I think it's basically down to running costs, water being a lot cheaper. As to putting it under solid boards, all the research I've been doing has flagged this up as a no no. They warp and twist and generally get very unhappy. 'Engineered' timber is the feller to go for. Like this

where you have a top layer of the wood you want - oak or walnut or whatever - bonded on top of a slab of ply.

 

[srw]

Thanks for that. Do you happen to know if you need a bigger boiler? We're taking out three radiators (two full size, one small) and putting in about 20sqm of underfloor heating. Will the boiler be working harder, or less hard? (I've been trying to google for an answer to this basic question, but getting nowhere fast.)

I don't have the faintest idea. It was done as part of a full refurb of the house, which involved replacing a very antiquated boiler anyway.

 

[User482]

We've got engineered wood (essentially expensive laminate) above a hot-water underfloor system, and it works quite nicely. The general idea of underfloor heating seems to be that the flooring acts as a big storage heater - the floor "feels" warm.

Laminate's actually a photograph of wood, which is printed onto paper and coated in melamine. It's much tougher than engineered wood (I have both in my house) and much cheaper, but it doesn't look nearly as nice. And it can't be repaired if you do dent or scratch it.

Swee'pea: the point about UFH is to run it at a lower temperature than radiators - so your boiler will be "working" less hard, but for longer. You'll also need to insulate below the UFH piping.

 

[threebikesmcginty]

I really fancy a caramel wafer for some reason!

 

[srw]

Laminate's actually a photograph of wood, which is printed onto paper and coated in melamine.

I didn't know that. No wonder it looks like crap.

 

[User482]

I didn't know that. No wonder it looks like crap.

But it's an ideal choice for a nursery - when it ends up covered in crap, you can't tell the difference...