Underfloor Heating- Single Zone System
The Underfloor Heating system can be fitted in both concrete and timber
suspended floors. For other floor constructions please contact us and we
will explain installation procedure, for example you can also do a floating
floor.
In concrete screeded floors, the screed acts to diffuse the heat across the
surface providing an even temperature at the floor surface.
Normally a concrete slab is laid over DPM. A 20 mm thick piece of insulation
is fixed to the perimeter walls, to a height to include the depth of floor
insulation and screed.
Whilst the edging insulation may be on show it is covered by wall plastering
and skirting boards. We do not supply the edging strip. Use 20 mm Celotex.
Floor insulation is laid to the whole area, joints are taped to prevent the
ingress of screed between the insulation boards. The floor is now ready for
the underfloor heating pipework installation.
We recommend a minimum of 50 mm Polyurethane insulation. If there is not
enough space for 50 mm insulation, 30 mm is recommended, but always check
that you apply to current building regulations. We recommend Polyurethane as
it out performs Polystyrene and it’s greater density allows for use of clip
fittings.
If you use Polystyrene insulation it is recommended that you install wire
mesh D49 on top of the insulation and tie the pipe with cable ties to the
mesh.
The pipe is laid at 200 – 300 mm centres dependent upon design. Care must be
taken to protect the pipework whilst laying the screed. Finally the floor
finish is laid.
Always check with the manufacturer of any floor covering that it can be used
for underfloor heating.
Timber suspended floors do not conduct heat as efficiently as screeded
floors. This means that the heat output is less.
Some manufacturers use heat emission plates to try and achieve an even
temperature on the floor. This is a very expensive way of installing
underfloor heating in timber suspended floors and at the end of the plate
the temperature is not going to be very high. Clearly there should be a
cheaper solution that works without using the very expensive plates. After
all, the first floor is usually timber suspended and on the first floor less
heat is usually required. Also note that the first floor is supplemented by
heat from the ground floor.
Our underfloor heating system is very simple and easy to install in timber
suspended floors. The system is based on thousands of installations that are
now working with total satisfaction.
Between the joists, a 50 mm Polyurethane insulation board is cut for a tight
fit. See picture above. It is advisable to use scrap battens from building
site to support the insulation from below.
The pipe is then clipped on the insulation with our special clips. Then the
floor boards are laid on top of the joists. Be careful not to leave too much
air space between the insulation boards and floor boards (25 mm is
recommended). The joists need to be notched where needed for pipe runs.
For ground floor timber suspended or buildings 20 year or older we
recommend;
To get the timber suspended floor to act as a screed floor and to give out
more heat, the air gap between the insulation and the floor boards should be
filled with a lightweight screed mix. This infill is normally also required
if you are mixing timber suspended floor and concrete floor on the same
floor level.
We recommend the infill for all properties that are not built to current
building regulations. The mix consists of 10:1 sand/cement mix or 8:1 Lytag
lightweight mix on top of the insulation, with enough water to hold the mix
together. The additional load imposed on the floor by the mix is approximate
18 kg/sqm. Note that the mix is not intended as load bearing, merely as a
heat conductor. The thickness of the mix should be 25 mm with the pipe
included in it.