Insulating garage's concrete floor for electric underfloor heating

2 years ago

Hello!

I have a 12m2 garage with a concrete floor that I would like to insulate and use electrical underfloor heating as it will become a home office. I'm doing it all myself but I’m not sure what is the best procedure and/or order of putting it all together.

My first idea was first to repair cracks and holes with mortar, then self level it as the concrete surface is full of tiny waves/grooves, lay a damp proof membrane, lay the 50mm PIR boards on top, then electric underfloor heating mats stick to the PIR boards, self-level again and then a laminated or vinyl floor.

The concerns and questions I have or were raised by talking to some people

* I may not need to self level the concrete slab to take these waves/grooves imperfections, the PIR boards once layed on top of them and walked on top should absorb these. True?

* 50mm PIR boards for a 12m2 garage could be overkill?

* PIR board should not be in direct contact with electric underfloor heating, I guess it can be burnt/melted by the wires? It seems I would need to add a separation layer, some suggested some concrete faced insulation boards so the heat from electrical wires would spread more evenly on the surface and not damage the PIR boards underneath

* Should I chipboard on top of the PIR boards (which has the wires and self level already in place) as they are weak and could get damaged easily with point pressure even with the self-level on top?

* Is chipboard the best option to add a hard layer between the PIR boards and the laminated floor?

* I was checking screed, but the requirement seems to be 50mm of screed on top of underfloor heating wires and that with already 50mm PIR board means a fair bit of headroom gone, plus the curing time for screed of several weeks. I was checking liquid screed with faster drying times, but I'm not sure it is worth the costs

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Insulating garage's concrete floor for electric underfloor heating

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