How to Install Tile Over Tar Paper Concrete Floor

If you seek the perfect subsurface on which you can lay your tile, tar paper concrete floor will be an ideal option. And it’s crucial that you learn the proper way it can be installed. 

A concrete slab is durable and very strong, making homeowners be at rest as it can give needed support to heavy tiles. Besides, this slab features fewer movement-related problems than a wooden subsurface, resulting in less stress to the tiles over time from contraction and weather-related expansion. However, one drawback is how concrete can be affected if exposed to moisture. So, with a layer of tar paper, a solution can be guaranteed.

So, how can you install tile over tar paper concrete floor? Please do this by cleaning the floor, marking some specific areas for later leveling, grinding the slab with a concrete grinder, cleaning the cracks, getting them filled, spreading the asphalt mastic along the edge of the tar paper’s width, spreading the tar paper, spreading the mastic on the tar paper, installing the tile on the mastic, grouting the tile after removing the tile spacers, and brushing the tile and grout sealer.

How to Install Tile Over Tar Paper Concrete Floor

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Can Tile Be Installed over Tar Paper?

An infused heavy-tar paper is a waterproof layer that helps seal off a surface and prevent anything beneath it from getting damaged by moisture during use. This implies that tar paper is the protective barrier between the mortar bed and the subfloor during stone and ceramic installation. 

Moreover, water can leak into the tiles via the slab if you don’t put between the surfaces a vapor retarder. Here, a tar paper layer will function effectively. After installing tile over tar paper concrete floor, the paper will protect the tile from water that could affect the bond between the concrete and the tile.

Steps to InstallingTile over Tar Paper Concrete Floor

Below are the step-by-step guidelines on how you can install tile over tar paper concrete floor:

Step 1: Clean the floor thoroughly

Start by cleaning the surface of the concrete floor. Do this by sweeping any debris or loose dirt away and using a pH-neutral cleanser to mop the surface. Use a concrete degreaser to wash any grease or oil from the floor, and use clean water to rinse cleanser residue away. Then leave the floor to dry before proceeding to the next step.

Step 2: Mark the areas for later leveling

Use a level bar to check the level of the surface. Drag the level bar’s long flat side across the slab’s surface while looking under the bar for any low or high area in the slab. Then mark the areas using a pen for later leveling.

Step 3: Grind the slab with a concrete grinder

Use a concrete grinder to grind the slab’s high level down to the surrounding concrete’s level. Then sweep away the ground concrete. Use a self-leveling compound to fill the slab’s shallow dips (1/8 inch or less).Use the flat of a trowel to spread the compound to make it even with the surface of the slab. Take the concrete mortar and fill the slab’s deeper depressions with it. Then, use the trowel to level the mortar to make the depressions level with the surrounding slab.

Step 4: Clean the cracks and fill them with concrete joint repair

Use a wire brush and concrete joint repair to clean the concrete cracks out and fill the cracks, respectively. Take the putty knife and use it to push the repair material into the cracks and drag the knife across the filled crack’s surface to scrape excess material away and level out the patch. Then leave the materials used to leveling and repair overnight to dry.

Step 5: Spread asphalt mastic along the tar paper’s width

Use a notched trowel’s flat to spread an asphalt mastic row along the width of the tar paper (the edge of the slab). Before going over the mastic to use the notches to raise the ridges in the mastic, you should till first the trowel to a 45-degree angle.

Step 6: Spread the tar paper

Proceed by rolling over the mastic a layer of tar paper–where it’s necessary to get full coverage of the mastic row, ensure you butt together the ends of the paper. You need another row of mastic, spreading it alongside the first. Do the coverage step again with the tar paper– ensure you only overlap each row edges by 4 inches.

Step 7: Spread the mastic on the tar paper

To notch the surface as it’s done with the underlayer, spread onto the placed tar paper a layer of mastic.

Step 8: Install the tile on the mastic

Install the tiles into the layer of mastic directly. Please do this by pressing them down firmly, ensuring full coverage of the tiled rear. To get even grout lines and rows, place between the tiles your tile spacers. Leave around the tile surface edges a 1/4-inch space between the wall and the tile-covered floor for expansion. Then leave overnight to make the mastic dry.

Step 9: Grout the tile after removing the tile spacers

Get the tile spacers out and grout the tiles. After spreading the grout over the tile, use a grout float to push it into the joints between the tiles firmly. Use a damp sponge to wipe the surface of the tiles to get rid of excess grout from the surface of the tiles. You need to wait for about 2 hours before using a clean, lint-free cloth on the surface of the tile to remove any leftover grout. Then leave the grout for about 36 hours to cure.

Step 10: Brush the tile and grout sealer

The final step is brushing over the grout a layer of tile and grout sealer to avoid staining the material.

Frequently Asked Questions (FAQs)

Please, review the questions below:

Do you need to put anything under tile on concrete?

Although it’s not compulsory to put anything under tile on concrete, the surface may need preparation for the tile placement. This is because uneven areas and cracks can damage the tile above, and the moisture in the concrete can affect the mortar and the tiles.

How long should concrete cure before installing tile?

Based on people’s suggestions, you will need a minimum of 28 days before installing tile under normal conditions. Nonetheless, most thinset manufacturers recommend 14 days if you use a premium latex-modified thinset.


You don’t want to see your concrete getting damaged by moisture. Since you are in for the protection of your tar paper concrete floor, try to follow the steps above. If you find it challenging to do it yourself, you can get in touch with the professionals.

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