Joe needs help [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : Joe needs help

seeing the sights
06-28-2019, 05:31 PM
Hello all, I'm new here. We have a basement floor that is 5 inches of concrete with wire reinforcement in it.
After 32 years, it shows no cracks and I plan on tiling over the concrete.

I have enclosed some pictures that show my over the top method of determining the flatness of the floor. After taking elevation shots I have a high spot about 6 ft by 6 ft. I plan on grinding that area down. After that my high to low elevation will be maybe 1/2 inch at most, and that is at the worst over 8 ft or so. Most areas show as little as a 1/4 inch over 12 ft or so.

I think if I try and use SLC I will make it worse. Also, I plan on using some type of tile leveling clip. I understand the leveling clips will not help with a floor that is not flat.

I have 2 questions: 1. Do I have to grind the whole floor or will the thinset stick to the floor as is (note the area that has a little vinyl glue left).

2. I plan on using 6 x 24 plank tiles, is the right trowel a 1/2 x 1/2 square notch. Also, is this project doable with an imperfect floor?

Thanks, Joe

Sponsored Links

06-28-2019, 06:17 PM
Should be beautiful. Level isn't important. Flatness is. Or planer. I see an old level. Cool. Reminds me of my survey days. Tell us how much it's out of plane? A string works well. SLC is expensive but can work well if your shooting for level and flat. You just need flat for those big tiles.

06-28-2019, 07:28 PM
I like to grind the whole slab just to make sure I'm down to raw concrete without paint or adhesive. But, grinding the actual concrete down 1/4 or more in places is gonna be quite a job.

I like using an 8 ft straight edge (or longer) to check the slab. Crawl around the floor and mark the low areas.

seeing the sights
06-28-2019, 07:29 PM
The marks on the floor are for level shooting ever 2 ft plan on useing 6x24 plank tiles. Will be grinding a high spot about 6ft x 6ft more pics to come.

Thanks, Joe

06-28-2019, 07:40 PM
I thought the lines were old carpet squares . Find the deviation from the plane. And let us know. A big floor grinder rented at HD can grind off 1/4" in a 6 x6' area pretty easy.

06-28-2019, 07:42 PM
Welcome, Joe. :)

FYI, tile industry standards require your substrate for those large format tiles to have no deviation from intended plane of more than 1/8" in ten feet nor 1/16th" in two feet. That's a very flat floor, but you'll be glad to have it come time to set the tiles.

My opinion; worth price charged.

seeing the sights
08-28-2019, 09:32 PM
Hello all, Its been a learning experience. I used SLC around the perimeter of the one side of the room that made it only about 1/2 off in 10 feet was 7/8 so Im good to go...........well not so thanks to dumb luck the way I laid the tile I could slowly drop the level of each row of tile with out lipage so not to be up in the heat register

Yes I know this is not the right way if I had to do it over 32 years ago when I was building the house would of had elevation stakes ever 2 feet when they pored the floor and would have used SLC before installing the kitchen cabinets they were installed 23 years ago.

This is a basement den/kitchenette

What I have learned is when you are told that a flat floor is needed it is if I would have laid the tiles 90 deg from the way I did I would not be able to do what I did to correct the un-flat floor.

Thanks for looking. Joe

08-29-2019, 10:09 AM
no decoupling membrane?

08-29-2019, 01:07 PM
Although I like using an anti-fracture membrane over slabs, he says there's no cracks after 32 years so hopefully he's okay.

08-29-2019, 02:22 PM
If I ever have another concrete slab poured. I'm going to have it written in the contract about some kind of off level monetary penalty and I'm going to hold half the payment back until the cement cured and I can get on it with my laser and I'm going to end up having them owe me money

seeing the sights
08-29-2019, 02:28 PM
Hello all, I understand that to alot of you its a hack job and it could be alot better but for the value of the home $300,000 and how far out of flat the floor was its ok.

We all see worst tile jobs everyday in public places.

When I see guys spending a day just to straighten out a wall before installing large tiles I know you guys are in a different league then me.

If I had to do it over I might have removed the cabinets and used SLC over the complete floor.

Thanks, Joe

08-29-2019, 02:59 PM
Joe, don't be so hard on yourself. This flatness thing takes a lesson like yours to really appreciate. We all bend tiles on the floor and walls like you did. Just take time on the wall painting and the trim and baseboards and it will really pop. I hope that wall paint color is going? haha IT is best to paint before tile so maybe your almost finished. Is there a pool table?
SLC for a room so big would be have been at least 1200$ for materials. 3/4" low spots then maybe 2000$

08-29-2019, 04:14 PM
Teddy, good luck finding a concrete man that will sign your contract. :deal:

seeing the sights
08-29-2019, 06:41 PM
LOL my wife picked that color and yes I painted the walls before tile.

I just install she picks colors and yes after my first tile floor on concrete job I have a new knowledge about when you guys say the floor has to be flat Thanks, Joe

08-29-2019, 07:27 PM
What Davy said.