Underfloor heating

Underfloor heating plans

Underfloor heating plans

Now we’re getting to the really interesting part, the point of no return with the floor! Putting in the underfloor heating is a job involving three different teams from Stan’s building firm, and slowly (well, quite quickly really!) the inside of the house takes on another guise.

The story so far: you may recall when we put the foundations in, we dug out the shape of the house and poured a concrete slab into the space. That slab has been the floor ever since. But now we’re ready to get a bit closer to the finished floor height.

The stack of insulation ready for laying down.

The stack of insulation ready for laying down. Nearly 100 square metres of 6 inch thick foam boards.

Pete getting stuck into laying the floor insulation boards

Pete getting stuck into laying the floor insulation boards

So on top of the 150mm of compressed hard core and 150mm of reinforced concrete, we’re now about to add 140mm of floor grade foam insulation, more than half a kilometre of underfloor heating pipes topped off with another 60mm or so of concrete screed.

The idea with underfloor heating is to pass warm water through the pipes covered in the screed and warm the rooms like that rather than with a radiator. Although it takes longer to heat a room up from cold, it does mean you don’t have to have the water quite so hot (45 degrees instead of 70) which is just perfect for our ground source heat pump. It takes a bit of tuning though, but with thermostats in each room controlling a different loop of pipework, we will eventually get it all under control.

Underfloor pipework on top of 140mm insulation

Underfloor pipework on top of 140mm insulation

Here you can see the 8×4 sheets of insulation laid down and taped together. These went down everywhere on the ground floor except under the hearth in the living room for the wood burning stove. (This means we can have a hearth the same level as the wood flooring rather than a raised hearth.)

Then Brian and Nicky paid a flying visit and installed the underfloor heating manifold and all the pipework. Brian said he wasn’t looking forward to pushing in all the plastic staples by hand but much to his delight the supplier (Myson) had included a dedicated staple gun that could dispense the staples while the operator just walked along the pipe. No kneeling down and the job done in 5 hours.

The manifold will eventually be hidden in a cupboard under the stairs.

 

The underfloor manifold - just needs a pump to be connected up (wires above and pipes below right)

The underfloor manifold – just needs a pump to be connected up (wires above and pipes below right)

Brian wielding the staple gun

Brian wielding the staple gun

Stapling the pipes down to the insulation - a quick job with two people and a staple gun

Stapling the pipes down to the insulation – a quick job with two people and a staple gun

Brian wrestling with the plastic pipework

Brian wrestling with the plastic pipework

The finished pipework in the dining room

The finished pipework in the dining room

Another pile of sand ready to mix concrete

Another pile of sand ready to mix concrete

So, now with all the pipework in place, we’re ready for the concrete screeding. Some builders use a very liquid self levelling screed and pump the mix into the house. From experience, Stan prefers to use a very dry mix, mixed on site and trowelled over the pipes. If required, a thin level of self levelling mix can be applied at the end where it’s needed.

Brian and Seely contemplate the dry mix

Brian and Seely contemplate the dry mix

Trowelling a dry mix is hard physical work

Trowelling a dry mix is hard physical work

Careful use of the spirit level required!

Careful use of the spirit level required!

Another barrow load

Another barrow load

The pipes are surprisingly robust - you can walk on them but better to lay battens just in case ...

The pipes are surprisingly robust – you can walk on them but better to lay battens just in case …

The resulting floor is remarkably level (although I wouldn’t expect anything less from Brian who is a bit of a perfectionist in these things). Examining it the day after, the conclusion is that there’s no need for any screed adjustments – ready for flooring, just as soon as it’s dried off enough.

Share Button
Posted in Updates  |  2 Comments

2 Responses to "Underfloor heating"

Leave a reply