Allow the thinset mortar used during tilework to cure for at least 24 hours before grouting. 48–72 hours of curing time is preferable, especially if temperatures are below 70℉ (21℃) or if you are working in a humid environment. If you grout before the tile adhesive has fully cured, your tiles may not fully adhere to the surface, leading to tiles coming loose. This rule should be followed whether you are tiling floors or walls, both indoors and outdoors.
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How Long Does it Take Thinset to Cure?
Thinset mortar used to glue tiles to surfaces requires at least 24 hours to cure. The reason this process takes so long is because air aids in the curing process. The mortar beneath the tile receives very little air, which makes the curing process slow. The spaces between the tiles will typically cure faster than the mortar beneath. Do not use visible mortar in tile seams as an indicator that your thinset has cured.
- Allow at least 24 hours for the thinset to fully cure.
- Portions of thinset exposed to air will cure faster. The spaces between tiles may seem dry, but the mortar may still be soft beneath individual tiles.
- If you are using a waterproofing layer beneath the tiles, allow 48–72 hours for curing.
Waterproofing layers underneath tiles, such as Ditra, keep tile floors moisture-safe and crack-free, but they slow the curing process. Because the waterproof barrier is non-porous, even less air reaches the thinset, slowing the cure time further. Thinset spread on top of a waterproofing membrane requires 48–72 hours to fully cure.
What Happens if You Grout Before Mortar is Dry?
If you apply grout before your thinset mortar has fully cured, you may halt the curing process. This leads to tiles popping free from your floor or wall, as well as cracked tiles. Additionally, the moisture in the mortar may disrupt the curing process of the grout, leading to discolored grout in areas.
- Grouting before thinset has cured leads to tiles popping free or cracking.
- Grout applied over uncured mortar will be discolored.
- Thinset that has not been given time to cure properly before grouting will crumble.
Uncured thinset reacts in unpredictable ways. A tile may come loose, taking part of the thinset with it. What you’re left with then is a useless tile and a floor with portions of hardened thinset fused to it. It is expensive and time-consuming work to replace tiles and scrape old mortar off the floor prior to reapplication.
Can You Wait Too Long to Grout Tile?
There is no harm in waiting more than 24 hours before you grout your installed tile. As long as the tile surface is kept clean and debris is kept out of the seams between tiles, you can allow your mortar to cure for as long as you wish before grouting. There’s no downside to waiting longer to grout, but it is a bad idea to grout too soon.
- You will not harm your tile job by waiting more than 24 hours to apply grout.
- If the tile is kept clean and debris-free, you can let mortar cure indefinitely before grouting.
- If you are not sure whether the mortar has cured or not, it is best to wait before applying tile grout.
Caution pays off. If your ceramic tile job seems damp or not fully set after 24 hours, wait longer before grouting. You will save yourself work by finishing the job right, rather than redoing a job ruined by uncured thinset mortar.
What Happens if You Walk on Freshly Laid Tile?
Walking on a freshly laid tile floor will disturb your tile installation, cause the tile to pull free from the mortar, and result in loose tiles going forward. Once you have tiled a floor, do not walk on it for at least 24 hours.
- Walking on tile floors that have not been allowed to set for at least 24 hours will cause tiles to shift, pop up, or dry improperly.
- Exposing tile floors to foot traffic too soon leads to loose tiles in the future.
- Do not walk on uncured tiles or expose them to water.
Similar to avoiding foot traffic, do not expose uncured tile to water or other liquid. Thinset mortar is diluted in water. Spraying freshly laid tiles with water will cause the mortar to turn into a thin slurry that won’t keep tiles in place.
How Long Should You Allow Tile Mortar to Cure Prior to Grouting?
24 hours is the minimum amount of time you should wait before grouting tilework. This amount of time allows the thinset mortar to fully cure and fuse to both the tiles and the floor. Waiting longer than 24 hours is advisable in cool and/or humid weather. Remember, there’s no harm in grouting your tile several days after you install it, but it is a bad idea to grout too soon. Applying grout too soon will stop the mortar curing process, leading tiles to pop loose from the floor or wall.
