Mechanically Polished:
Not all concrete floors are ideal for polishing, in fact a high percentage of existing concrete surfaces will not produce the strength and high sheen exposed aggregate finish that the home or business owner envisioned or expected. Unfortunately most homeowners see a floor with a high gloss sealer on a ground concrete substrate and assume that this is polished concrete. However this is not the case and more often the application they are viewing is a “grind and seal”.
Polished concrete is not sealed. These floors are brought up to the higher grit levels and have been chemically hardened (densified). Polished concrete without the densification step will be much more susceptible to staining, dusting and abrasion. They will provide a high gloss finish that is relatively stain resistant for a surface without any form of sealer. Polished concrete floors are not stain proof as so many people are led to believe and even with a stain guard added, a floor may still stain. A stain guard will usually only give added time for the clean up….
In general, a mechanically polished floor is ground to the level of exposure required by the client, grouted then densified. After using the metal bond diamonds to grind the substrate it will be polished to the finish required using resin pads. The process generally takes some time, as there are many steps involved.
Grind and seal:
Is exactly as the name implies. The concrete substrate is ground back generally up to the 200 grit level and then coated with a topical concrete coating/ sealer. These coatings can either be acrylic, epoxy or polyurethane.
There are some benefits to a grind and seal over polished concrete:
o Less labor intensive
o Depending on the sealer used they may offer higher abrasion resistance.
o Cheaper per m2
New concrete is to be at 32 mpa and will need to be laid by a concreter ensuring it is flat with no screed marks or footprints. The mix and method laid is critical for a quality finish and will keep your costs down when grinding. Any additional grinds will cost you more….
If you’re thinking of having a new or existing floor polished or grind and sealed then do your homework.
It doesn’t hurt to quiz your contractor. Ask them about their process and what products they use. Especially for a grind and seal. Not all sealers are created equally and some may deteriorate faster or yellow over time…
Selling a polished flooring system and delivering a grind and seal is a common occurrence. Selling a polished concrete floor and not offering the advantage of the densification process while still charging top dollar is also a common occurrence.
So do your homework and quiz, quiz, quiz…….
Grrr ind
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