To self-level or not garage concrete floor with "grooves/waves" to convert to home office

[alex889]

Hello,

I'm trying to figure out if self-levelling for my garage floor is needed for my home office conversion. There are grooves all the way which some are up to 5mm deep. I'm planning to insulate the concrete floor on top with PIR boards of around 100mm and I was wondering if these grooves will affect them. In theory, they should take some of these grooves into the board once I step on top, but also there are so many and the weight on top may not be enough to make them sit properly now, but maybe later with furniture on top it will and then that will cause some movement on the floor. What do you guys think? My plan is to add a damp proof membrane on top of concrete, 100PIR boards, foil tape in between them or perhaps another DPM sheet to avoid any moisture from above sinking into the boards, 18 or 22mm chipboard on top, then a thin plywood layer as I'm planning to carpet on top. What do you guys think?

 

[Deleted member 174758]

Dry sand to fill the grooves, DPM, PIR, floating floor. Where do you think you'll be getting the moisture from above from?

 

[sxturbo]

As job and knock said,

The moisture will be coming from the floor not from above, unless you have a leak, which as your turning it into an office one would assume not.

 

[dazlight]

Put a coat of ardex NA or any moisture tolerant smoothing compound over it. Then a liquid Dpm.

 

[alex889]

Dry sand to fill the grooves, DPM, PIR, floating floor. Where do you think you'll be getting the moisture from above from?

Floating floor you mean floating chipboards?

Moisture from bellow and above the insulation, I heard any moisture can ruin the PIR boards, but also I was trying to be pro active with any water cup being dropped on the floor, but maybe that is me being paranoid

 

[Deleted member 174758]

Yes, floating chipboard. Use P5 tongue and groove chipboard. It's moisture resistant. Good brands include Egger and Caber (both manufacture in the UK). Use D4 flooring adhesive and flooring straps, or a flooring slide hammer or a pull bar and hammer to assemble the boards in a brick pattern