Looking for advice - Slate cleaning and re-sealing


New Member
Dec 6, 2019
Real Name
Justin Nicholas
Hey guys, I am going to bid a job later today and wanted some advice. Customer has slate floors, and says they were sealed about 15 years ago. She wants them cleaned, and then re-sealed. Will they need to be stripped first?

I keep a stock of GM for tile jobs, can it be used on this with my turbo force? I have yet to re-seal slate, what is a good product for that? How should I go about pricing this?


Well-Known Member
Sep 28, 2014
Real Name
Peter Dymond
Depends on what sealer was used before.
Go by and do a couple of tests to see.
Water drop test to see if there's even any sealer left.
Scratch test to see if its topical
Stripper test (floor wax stripper) to see if it comes off.

If its an impregnated sealer, it beads up water but no surface topical sealer present, then just clean and reseal.
If its topical it will need to be stripped first.

Groutmaster is fine. Slate is acid resistant too, so an acid cleaner can be used if there us effloresence or water mineral staining.

Then use a good quality impregnating stone sealer.

Pricing varies significantly by region.
Try to estimate time and multiply by your hourly rate.
Add 10% for supplies, like sealer, more if its a small job and you don't have sealer in stock.

There are many great stone sealers available.
Stone Pro or find it locally.
Just make sure its impregnating not topical!

Also find out if the customer wants wet look or not, as enhancing impregnating sealer will do that.