If the water soaks in you re good to go.
Tile on concrete slab with cracks.
Sweep the concrete floor with a broom to remove any visible debris.
Concrete is similar enough to tile in terms of expansion and it doesn t flex so you don t need crack protection just use a decent polymer modified mortar.
Before you install any flooring material over a concrete slab it is important to inspect the slab for defects.
Applying tile in these situations is really quite simple.
If you watch them tile a commercial center or office building which are always concrete floors you never see them use crack prevention.
For small narrow cracks that do not show signs of moisture use concrete filler which can be.
In some cases the crack may instead occur in the grout joint.
But larger cracks especially those that are higher on one side than the other may telegraph through the tile and cause it to crack.
Dips bulges and cracks occur frequently as concrete cures and ages.
The drying would cause shrinkage or compaction of the dirt possibly enough to create a void under the slab followed by the slab cracking and settling over the area of the void.
Cracks are nothing out of the ordinary.
How to lay tile over cracked concrete cleaning the concrete.
Cracks in concrete floors or slabs occur in poured concrete slabs may be found both in basement and in slab on grade or patio home construction and have a variety of causes and cures that we discuss here as we explain how to repair cracked concrete floors and as we describe slab on grade construction or patio home construction cracks and as we review the diagnosis of cracks in ceramic tile over concrete slab floors.
Let the primer dry and then apply the membrane photos 3 and 4.
Concrete can support a lot of weight in compression but is weak in tension.
If you are placing tile on the slab it s important the control joint line up with a control joint in the tile easier said than done.
Using a scraper and a wire.
Tom meehan a tile installer and owner of cape cod tileworks in harwich massachusetts replies.
To find out if a concrete slab is clean pour a little water on it in spots.
Instead of a crack transferring from the concrete to the tile the crack isolation membrane absorbs the crack energy and spreads it over a large area preventing telegraphing through the tile.
With the cracks patched apply a latex modified crack resistant thin set.
Although it s unsightly it s very easy to fix and it s a much better alternative to a crack in the tile.
Then prime the concrete see photo 2 with the recommended solution consult the membrane manufacturer s literature.
Cut the membrane so it s 1 1 2 times the width of your tiles.
If tile were set on.
Small cracks caused by shrinkage usually do not present a problem.
So random cracking might be a better approach for tile.
