subfloor over concrete for hardwood - Page 2 - Contractor Talk - Professional Construction and Remodeling Forum

mrghm · 05-01-2009, 10:06 PM

Sika have changed the installation instructions to say not to be used with soild hardwood.

The T55 remains flexible but the T53 dries ridged.

a major job that used an engineered flooring also failed as the engineered floor was not stable and had to much movement.

the system works great when used with 3/4 ply & then hardwood.

ian@prosource · 05-02-2009, 12:47 PM

hi mrghm,

I have looked again at the spec sheet and they all say for use with solid & engineered woods,

we have a Sika factory on the next block and i have spoken to them again & also attened a training/info session with them on these adhesives some months ago as well as using them myself in the past,and never had this problem. we also have a part laid floor sample on display (made up six months ago) the adhesives when cured are still flexible even now,

sounds like you may have had a bad tub or two, as laying over 3/4 ply instead of concrete should not make any differance with how the adhesive sets, ie ridged/flexible. the adhesive should curl the same on either surface.