Tiling concrete floor without damp-proof membrane

[Roger Moss]

I am about to tile the concrete floor of a boiler hut. The floor is dry

- it is on sloping ground and well drained - but reading the instructions on the bucket of tile adhesive for concrete floors, they are quite particular that the floor should have a damp course.

Is this because once the floor has impermeable tiles over it, it will get damp and the adhesive will dissolve back to a sticky state? Would I be better sticking them down with mortar?

Thanks Roger

[meow2222]

yes, no more large evaporation surface.

no, it just loses some strength and fails early

Most tile adhesives are modified cement mortars.

You could go the modern way, but there are plenty of old tiled floors that have lasted a century plus with no dpc. A simple way to help them achieve this is to use a grout that will evaporate any damp.

NT

[mail]

Dear all =2E.or you could use a water-"proof" epoxy mortar that acts as a dpc (many on the market - consider Sika or Ardex?) Chris

[Roger Moss]

[e-mail] wrote:>

The stuff I've got is Unibond's "Tiling for concrete floors" extra strong waterproof tile adhesive & grout - sounds just the stuff until one reads the warning about needing a DPM. Presumably being waterproof this wouldn't let damp evaporate?

- Roger

[Stuart Noble]

If the adhesive was waterproof, why would it need a dpm? If the floor is dry now, I'd tile away. It's only Unibond trying to cover their arses. If there is any damp in the future, precious little is going to evaporate through the grout anyway