Use a trowel to apply and use the edge to ensure the patch has edges level with the surrounding concrete.
Concrete slab preparation for tile.
Cut the membrane so it s 1 1 2 times the width of your tiles.
With the cracks patched apply a latex modified crack resistant thin set.
Let the primer dry and then apply the membrane photos 3 and 4.
There are different kinds to choose from.
Some also keep water out of the installation area.
To prepare your concrete subfloor make sure that it can accept water penetration.
Ideally you want a rh of about 75 to 80.
Crack isolation membranes keep imperfections in the concrete slab from spreading up to the tile.
The basics the bulk of the work for a new slab is in the excavation and form building.
There are two reasons for this.
Before you get to work take the time to gather the supplies and tools you ll need.
There are epoxy coating systems for applying a vapor retardant over the concrete slab surface before you tile over it.
These cracks may eventually show up in tile or dressing applied before the 28 day curing period.
Then figure on spending a day building the forms and another pouring the slab.
The substrate for tiles shorter than 15 inches must be so flat that it varies no more than 1 16 inch per foot according to the ceramic tile education foundation.
If you have to level a sloped site or bring in a lot of fill hire an excavator for a day to help prepare the site.
With ceramic tile you might be able to get away with up to 90 depending on the tile and installation products you are using.
Cracks and depressions may create weak spots that cause tile to crack in the future.
New concrete must cure a minimum of 28 days before either tiling or putting a dressing onto the new concrete.
How to pour a concrete slab.
No matter how dirty or clean the concrete floor looks start the process by sweeping the floor.
1 as the concrete cures drying and shrinkage cracks could occur.
Additionally a steps must be taken to ensure that a concrete floor will create a solid bond.
Then prime the concrete see photo 2 with the recommended solution consult the membrane manufacturer s literature.
Patch little cracks or holes with a cement patching compound.
Test by sprinkling water on various areas of the subfloor.
As with a wooden subfloor a concrete subfloor must be level for successful tile installation.
Don t lay tiles on a concrete slab with cracks that appear to be spreading or irregularities that prevent you from leveling it.
Masons often use a crack isolation membrane when setting tile outdoors.