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Cutting control joints in polished concrete floor
- Thread starter tookien
- Start date
Rusted Nut
Well-known member
To polish concrete, the concrete has to be cured; so cutting control joints at this point won’t do much good.
Walkers
Well-known member
Yep, iirc the concrete has to still be green. So just enjoy your concrete before it cracks.
ConCretin
Well-known member
Polishing and densifying typically occurs after a slab has reached strength. If that's the case, it's far too late to control cracking with control joints. Your slab has cracked as much as it's going to. If you want to cut some lines for decorative purposes, you shouldn't have any problems doing so but if it's not done well, you will have permanently messed up your new floor.
The reason I am doing it is mostly for aesthetic / decorative appeal primarily.
I won't be going more than 5/8th of an inch in.
I just want to know if the segmented diamond blade will be adequate as the polished concrete was densified, and thought maybe the densified concrete would give some trouble.
It seems ConCretin has answered my question though.
Thank you once more
I won't be going more than 5/8th of an inch in.
I just want to know if the segmented diamond blade will be adequate as the polished concrete was densified, and thought maybe the densified concrete would give some trouble.
It seems ConCretin has answered my question though.
Thank you once more
Yep, iirc the concrete has to still be green. So just enjoy your concrete before it cracks.
The concrete has already cracked long ago.
I am doing some maintenance to it.
It's just all about aesthetic appeal at this point.
ConCretin
Well-known member
Densifier isn't going to maker the concrete noticeably more difficult to cut. The question is the best type of saw to use and whether to cut wet or dry. Do you want to deal with dust or slurry? The other thing to consider is that the smaller the device & blade, the closer you'll be able to get to walls, etc but the harder it will be to get a straight cut. Is it a finished space? Can you use gasoline powered equipment or would electric be required.
As I sit here, I'm not sure what I'd use. Early entry saws are made for this but won't work well on hardened concrete. Larger walk behind saws would be fine for larger areas, are relatively easy to keep straight and work with water. If it's a small area, you might be stuck with a circular saw, which would be painfully slow and dusty. What's your plan?
As I sit here, I'm not sure what I'd use. Early entry saws are made for this but won't work well on hardened concrete. Larger walk behind saws would be fine for larger areas, are relatively easy to keep straight and work with water. If it's a small area, you might be stuck with a circular saw, which would be painfully slow and dusty. What's your plan?
Densifier isn't going to maker the concrete noticeably more difficult to cut. The question is the best type of saw to use and whether to cut wet or dry. Do you want to deal with dust or slurry? The other thing to consider is that the smaller the device & blade, the closer you'll be able to get to walls, etc but the harder it will be to get a straight cut. Is it a finished space? Can you use gasoline powered equipment or would electric be required.
As I sit here, I'm not sure what I'd use. Early entry saws are made for this but won't work well on hardened concrete. Larger walk behind saws would be fine for larger areas, are relatively easy to keep straight and work with water. If it's a small area, you might be stuck with a circular saw, which would be painfully slow and dusty. What's your plan?
Hey, thanks for the response.
My plan is to get some OSB cuts secured with a few concrete screws and line up the circular saw to ensure I get some straight cuts as I don't want to mess it up.
I want to avoid dust and use some water, so wet, going really slow and steady.
The area is about 18 by 20 feet.
I want to divide the 18 by 3 so 6 foot sections. and cut one in the middle of the 20 at 10 feet.
3 control joints in total across.
The plan after is to seal the joints up as well as the thin hairline cracks with epoxy, and then polish it out.
Walkers
Well-known member
Gotcha. I have cut deep and long with the diamond blades in a skillsaw, usually not for decorative purposes. Easiest with a helper holding a spray bottle of water and a shop vac.The concrete has already cracked long ago.
I am doing some maintenance to it.
It's just all about aesthetic appeal at this point.
Rusted Nut
Well-known member
Have a good supply of water and a shop vac handy, as the slurry will stain even polished concrete if it sits there at all.
Have a good supply of water and a shop vac handy, as the slurry will stain even polished concrete if it sits there at all.
Would it stain unpolished concrete?
Rusted Nut
Well-known member
Yes! Best to have two people, one cutting, one vacuuming. Rinse well before it dries.Would it stain unpolished concrete?
Yes! Best to have two people, one cutting, one vacuuming. Rinse well before it dries.
Thanks. What about polishing the concrete wet as I need to do some of that in some areas before moving on to higher grits. Does that need to be constantly vacuumed?
Rusted Nut
Well-known member
Not sure, never seen it polished wet.Thanks. What about polishing the concrete wet as I need to do some of that in some areas before moving on to higher grits. Does that need to be constantly vacuumed?