Why is my Grout Cracking?!

Hi Neighbors!

Why is my grout cracking?! This is a common problem that can easily be prevented in a number of different ways. All manufacturers provide installation information for each tile they make. The grout is the last piece of the puzzle and the first problem a consumer notices. Most of the time, there is an underlying problem with the installation or the subfloor rather than the grout itself being mixed or installed improperly.

It is important to understand there are many steps in a proper tile installation. It is imperative your contractor, and installer, is knowledgeable about your particular grout choice and your tile selection. Not all grouts are created equal, and not all tiles require the same grout.

The most common reasons for cracked grout are as follows:

1. Excessive Deflection in the Substrate - Movement in your subfloor can cause the grout to crack, and if severe, can cause tile to crack.

2. Grout that is insufficiently packed into the joint - If insufficient force is used while grouting tile, it is easy to "bridge" the joint, meaning the grout does fully reach the wall and/or floor between the tiles. This is especially true if sanded grout is used in joints narrower than 1/8". The sand grains can easily "bridge". This grout may only look complete on the surface and have little strength to stand up to movement.

3. Grout made with an excessive amount of water or polymer additive - The liquid that goes into the grout ultimately must evaporate to dry the grout. This evaporation can cause pinholing in the grout and a weak grout structure.

4. Grout packed after cement hydration started - All cement based materials have a pot life. If water is added to the mix after the grout begins curing in the bucket, the grout will be sufficiently plastic to pack but will not cure into a hard homogeneous block - it will be crumbly and weak.

5. Improper thinset coverage and/or improper thinset selection - When spreading thinset, your installer should first "burn in" the thinset to the subfloor using the back side of the trowel. Trowel notch size varies depending on the size of tile being laid. Notches should move in one direction across the subfloor. When a tile is set into the thinset, if you pull it for inspection, you should see 90% coverage of thinset on the back of the tile. There are several thinset choices. THERE IS NO UNIVERSAL THINSET. Selection must be made on the following considerations: tile size, traffic of the area, subfloor material, tile material.

6. Improper or lack of expansion joints - Because the subfloor in a home is constantly moving, you must have expansion joints for the tile to move. The perimeter of the room should be caulked rather than grouted. This includes a shower where wall tile meets floor tile and where wall tile meets wall tile. If you have a long room of tile, standards require a flexible joint, of either caulk or expansion strip, in every 20' of tile.

I realize there are many technical terms used above, and we are always glad to explain, in layman's terms, the possible reasons for your grout problems. As stated above, there are preventions for grout cracking. The flooring industry has realized this is a major problem for most consumers and we have worked hard to find solutions. Many times, finding a certified and knowledgeable contractor and installer is your best defense for cracking grout. Make sure to request referrals and references. If they are professionals, they will have referrals.

Below are a few options to help lessen the chance of grout problems:

1. Hire a professional tile installer - Professionals, with referral sources, have been trained to look for subfloor problems before installation. They understand the differences in tiles, thinsets and grouts. They will check your floor joists before deciding on a plan of installation.

2. Use an uncoupling membrane - This is a piece of material installed between the subfloor and the tile to help the tile move independently from the subfloor removing the pressure from the tile. Schluter's Ditra is one of the best examples of this flooring. Crossville Wholesale Carpet stocks Ditra and we cut by the foot for your project. Click here to learn more about Ditra or watch a short video.

3. Do not use a cheap grout - Why ruin your $2000 tile installation over a $15 bag of grout? You do not have to use the $150 bag to have something that will work well, but know that if it is cheap, it is cheap for a reason...

4. Select a grout with an anti-crack guarantee - Not all grouts are created equal. The more expensive grouts on the market offer anti-crack guarantees. The base materials and additives allow them additional flex. When pressure comes from the tile, they have some give, preventing the cracks from occurring. This is not a solution if your subfloor has extreme deflection. One brand we like is the TruColor by Bostik. This grout also offers antimicrobial additives to lessen the possibility of mildew.

5. If you purchase grout, ask about the need for caulk - Caulk is necessary in showers and areas larger than 20' of tile. It is recommended on backsplashes and the perimeter of your room. This means the perimeter of all rooms. Grout should never be installed against the wall, under your baseboard. This is an area which requires caulk or no material.

The Tile Council of North America has many recommendations for installing tile. Are all of them necessary? The answer is no. They are simply recommendations. If you follow their recommendations, or select and installer who will, your chance of having a failed installation is greatly lessened. Visit the TCNA website for more information on installation.

At Crossville Wholesale Carpet, we strive to deliver the best information to our customers. We want you to have a quality installation coupled with stunning products. If you have any questions or concerns, please do not hesitate to give us a call. Our sales staff is highly trained and committed to continuing education to provide you with the most reliable information on flooring products. 

 return to main page