Concrete floor repair for small washroom

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Posted by: from Vancouver
5/25/2020 at 12:53:52 AM

Hello all, I have 4 questions about some concrete sub-floor repairs.

I recently pulled up the linoleum in my washroom and am going to install vinyl planks so my plan for preparing the concrete floor is;

Clean up concrete floor surface with a wire cup brush on an angle grinder.

Brush on a bonding adhesive.

Pour down floor leveling concrete.

1st question:

I am only at the 1st stage of cleaning the concrete floor with the wire brush and am wondering how far down I should be taking it. Currently I have made the surface smooth and shiny, so taken off the grey, rough part of the concrete. Was this correct or too much ?

2nd question:

Also, as shown in the pictures, when I pulled up the linoleum some concrete sub-floor came up with it.

My question is, should I keep chipping away and remove this layer of concrete (which I suspect is self leveling type) or should I leave it and pour the self leveling concrete down?

3rd question:

As shown in the pictures, the drywall has a gap about 1/2" from the floor. Is this ok, and if not what should I do to fix this?

4th question:

As shown in the pictures, around the toilet flange there are big gaps.

Should I be filling these in or just leave them as is ?

If I do need to fill it in, what method and materials should I use to do this?

Answers for any of these questions would be greatly appreciated along with further tips and advice. Thank you.

Concrete floor repair for small washroom
Concrete floor repair for small washroom
Concrete floor repair for small washroom
Concrete floor repair for small washroom
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Herver from 3A Contracting in Regina
Date/Time5/25/2020 at 11:39:01 AM

To answer your questions.

1- if you have a smooth floor you are good, the point here is to not have any bumpy or old chunks of glue, try a heat gun to soften it, and then pull it off. The remaining glue can be scraped with a floor scraper or soaked overnight with water and dish soap, which helps soften the glue. Again, use a paint scraper to remove the linoleum glue that is remaining.

2- I would encourage you to remove any loose sub-floor, this way you are not jeopardizing the structure of you new sub-floor once you poor the new self leveling concrete.

3- The drywall is ok, the gap that you see is normal to have this allows for expansion without cracking the drywall. Also, this protects your walls from water damage and allows the walls for air circulation ( basically, many great reasons why to leave that little gap there ) . NEVER put a drywall against the floor.

4- just leave it as it is. (remember, concrete expands and contracts )

Note: Make sure you vacuum the surface before pouring the cement. make sure to put a wood or stiff cardboard to stop it from running into areas you don't want it to go.

best of luck with your project!

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Date/Time5/29/2020 at 8:18:37 AM

The wire brush will not work. It just melts and spreads to glue around. Even if it looks clean, there is still a residue on the surface which will effect the bond of your top coat. Get a concrete surface grinding cup for your grinder $50 and a vacum attachment $80 (Milwaukee makes a nice one). Grind the entire area until your down to clean concrete.

Any loose concrete needs to be removed. If it's not bonded correctly, chip it all away.

The drywall gap is normal and will be covered by the baseboards.

The most important things is that the toilet flange is mounted solid. If you can't move it side to side or up and down, then it's fine. If it does move at all then you need to chip the concrete all the way around it and pour new concrete around it.

PS don't forget the bonding adhesive when pouring new concrete products.

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