On 20/05/2019 22:12, ARW wrote:
On 20/05/2019 21:43, Jeff Layman wrote:
On 20/05/19 16:55, Steve Walker wrote:
On 20/05/2019 16:38, R D S wrote:
I want to overboard a draughty, uneven floor.

And as I could do with raising it about an inch I was thinking about a
thick insulation inbetween.

Then I started thinking about UFH and there are pre-grooved polystyrene
panels that would be ideal.

So just wondering if anyone has any experience of DIY UFH or any
opinions of UFH in general.

The system we have in the conservatory is embedded in the screed, but
could have been used as you mention.

Our add-on system runs off the normal central heating, via a motorised
valve and unvalved return (like a radiator), but that is far too hot, so
there is a blending valve and a separate pump.

Water is circulated by the dedicated pump, from the floor, through the
blending valve and back to the floor. If the water is too cool, the
blending valve mixes it with some from the main central heating and the
excess naturally exits to the main system.

It works well, but there is about 4" of screed, so warm-up and cool down
are slow. You need to have the heating on well before you need the room
and off well before you finish using it.

Cats love it though!

We had a conservatory put up about 5 years ago. Floating floor with
concrete beams and breeze block, covered with screed and 75 or 100 mm
of Celotex (I can't remember the actual thickness). Then laminate.

The UF heating was by electric film - 1.8kW. At the time, we
considered hot water - either UFH or radiators, but connecting it up
to the current HW system required approval, and the boiler was running
pretty near to capacity anyway. But we find the UFH is not sufficient
to keep the conservatory warm in winter, and is very expensive to run.
Really, there aren't enough decent days in winter to merit using the
conservatory anyway, and when it is sunny that will supply a useful
amount of heat, and it can be supplemented with a fan heater. I'm not
sure that any type of UFH in a conservatory is justified unless the
conservatory is triple or quadruple glazed.


Jeff, I have yet to find any justification for a conservatory.

When you have a house with a hall, kitchen (small and only for cooking,
not eating) and a through living room, plus three children, you want
another downstairs space! Self-building a conservatory was the cheapest
option and, at the time, the only financially practical one. Insulated
cavity walls, partial solid roof, double glazing, triple-wall roofing,
blinds all round and under-floor heating, make it practical to use for
almost all the year - hot summer days are the only problem.

As the rules have changed, we may change the roof to keep some of the
sun out.

SteveW