Do i need insulation boards

**B Endsor Tiling** · 13-09-2010

I have a kitchen floor to tile for a builder who is using the electric underfloor heating and was wondering if he needs to use insulation boards .the floor is 50mm sand and cement screed layed over 80mm kingspan

doug boardley · 13-09-2010

50mm screed seems a bit shallow for a screed imo, but insulation boards will help with the warm up to the floor surface as you won't be having to heat the screed as well.

**Dan** · 13-09-2010

The extra cost of insulation will always be clawed back through running costs, over time.

Though that aside, the performance of the UFH will be drastically increased if you use insulation. The warm up and cool down times are both improved meaning with a digitial thermostatic controller the heating will only ever be on when it needs to be.

**Phil Hobson** · 13-09-2010

Originally Posted by doug boardley

50mm screed seems a bit shallow for a screed imo, but insulation boards will help with the warm up to the floor surface as you won't be having to heat the screed as well.

Me to Doug, 50mm a bit tight. Maybe Ajax will give his unrivaled expertise on this. I would havt hought 70mm

**Ajax123** · 13-09-2010

Minimum BS for sand cement floating on insulation is 65mm.

If you don't use insulation the electric heating mat will have to work very hard as you will end up trying to heat the screed as well. That will significantly impact response times, costs and life span of the heating system. It will also act as an uncoupling membrane for the tile face so the defficient depth of screed won't cause a long term issue.