REPAIRING MINOR HOLES IN A CEMENT FLOOR BEFORE LAYING TILE

Source:www.stonediamondtool.com Date:2020/1/8 Read:313

Smooth your cement subfloor before laying tile to ensure that the tile has a flat, even bed on which to rest. Dips and cracks in the subfloor can cause tile to tilt, settle or crack. Filling minor holes in the cement can be time-consuming, but it saves you time and money later by improving the quality of your tile installation.

Preparation

Before you fill the holes in the cement, make sure the holes are fully clean. Dust and sand can prevent the filling compound from setting properly and bonding to the original cement, so vacuum the floor thoroughly. Then, wet the inside and top of the holes with a mop or sponge. Cement is absorbent, and it will suck the moisture out of the filling compound if it isn't already wet itself, causing the compound to dry out and crack. Wet the cement enough that it feels damp but not enough to flood it.

Filling

You can fill small holes most easily using a premixed concrete patch. Some products require you to add water, while others only need to be stirred; follow the manufacturer's instructions to determine how to use the compound you choose. Apply the filler to the holes with a putty knife or trowel, and press it into the holes so they are packed full. Scrape the excess off the surface of the cement so the patch sits level with the rest of the floor. If the cement has cracks as well as holes, fill them the same way.

Troubleshooting

If you can't find premixed concrete patch, you can make your own by mixing one part cement to 2.5 parts fine sand. To fill holes deeper then 1/4 inch, apply at least two layers of the cement patch. To make sure the patch sets properly, cover it with plastic sheeting for about five days. Once a day, wet the patch with a small amount of water to make sure the cement doesn't dry out the compound.

Other Considerations

To repair larger holes in cement, undercut the area before cleaning and filling it. Chisel the bottom of the hole until it is flat, and enlarge it slightly so the bottom of the hole is wider than the top. This creates a lip of the original cement over the hole, so when you press in the filler, the original cement holds it in place. Before tiling the floor, level any raised patches with a handheld concrete grinder. Grind slowly and carefully -- if you remove too much concrete, you'll create another hole to patch.