Electric Underfloor heating and tiles – why you should insulate
When you are considering using this great innovation don’t kid yourself about the need for insulation.
You do need it, and it is worth the extra spend.
Tile/stone flooring feels lovely when it’s warm – just imagine standing barefoot outside on your patio when the sun has been shining on it all day – how nice is that?
1 . Reflecting heat upwards
Heatmats/cables will warm up what’s beneath them by transmitting heat downwards, as well as upwards so if that’s into a concrete floor, or a screed of any kind then unless you use insulation boards your heating will be wasting your money trying to heat what’s beneath your tiles.
It will take ages for your floor to get nice and warm and you will waste energy along the way before the ambient air temperature is affected and rises to a pleasant level.
Even if you have Kingspan or similar domestic insulation below a screed, if you are installing the heating onto that screed you still need to insulate.
2. Thermal barrier
The efficiency of any heating is about how rapidly that heat is LOST, not about the power of the heat.
A bonfire is a very strong heat source but a field loses its heat everywhere around it very rapidly!
When you press your hand onto a window – it feels cold this is because the warmth in your hand is being transferred into the glass – heat loss!
If you are tiling onto a suspended wooden floor with a void beneath it, that void will suck heat out of the room above in the cold winter months.
Cold is allowed to penetrate from below unless there is something to stop it.
Kingspan or similar insulation will help however these are commonly screeded prior to tiling – see above
Insulating boards like Thermalite or Marmox create a thermal barrier that stops cold penetrating from below and makes your underfloor heating more efficient.
Thermalite board is non-structural and only suitable for solid concrete floors. It is a low-cost option
Jackoboard is structural and waterproof, as well as insulating so it can be screwed to wooden flooring instead of plywood to provide strength, it’s an excellent substrate to tile onto, and it has very high insulating properties. The perfect answer for a first-floor bathroom when tiling over a wooden substrate.