Can You Thicken Runny Grout?

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The formula appears simple on paper, but putting together the correct amount of liquids to dry for a cohesive adhesive for tile can be a difficult endeavor. If the grout is too dry, then it won't allow the tile to get a good purchase on the filling. There are a few tips to ensure your grout is the correct consistency for a long-lasting binding relationship with the tile you've so carefully chosen to lay down.

Can You Thicken Runny Grout?
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The Purpose of Grout

Grout gets a bad reputation for being difficult to create, slop down and maintain. The putty-like filler is vital to a well-crafted tiled project. It keeps the tile, no matter its shape, firmly in place and in line with its fellow shining shingles. Make sure you are using the correct grout for your job. If you have joints that are less than 1/8 inch thick, an unsanded grout will make the job easier and offer better adhesion for those narrow nooks and crannies. For thicker joints between tiles, a sanded grout offers less shrinkage for a cleaner finish and a longer-lasting bond between the grout and the tile.

Best Consistency for Grout

When you mix grout, no matter if it is sanded or unsanded, you are looking for a consistency that is thick and almost like wet clay. Mixing sanded grout to a consistency of peanut butter – and not the chunky kind – can ensure you won't have any cracks or shrinkage issues. You want a smooth, thick paste with no lumps or channels of dry grout running through the mix. If you don't mix it properly, it may still adhere to the tiles and keep them in place, but you will have pits and crumbling in patches around the tiled area. If it is too dry, it can cause cracks in the tiles as the house settles. If it's too wet, it won't adhere properly to the tiles and will leave you with a slanted mess.

Too Much Water in Grout

After following the grout manufacturer's directions and adding the correct amount of water and mixing, let the grout sit for at least 10 minutes. This is called slaking and will assist in not adding too much water or mix as you go. If you have too much water in the grout, the mix will be runny and will clump as it pours off the float. Add a small amount of latex additive into the mix. The sticky substance adds creaminess to the mixture. If the grout is more like a broth-based soup, you may need to ditch the entire batch and start from scratch. If the grout looks chalky, it could be that you need to let the grout cure for up to two weeks. Clean the surface with a commercial cleaner after it has cured.


Kimberley McGee is an award-winning journalist with 20+ years of experience writing for a variety of clients, including The New York Times, Las Vegas Review-Journal Home section and other national publications. As a professional writer she has researched, interviewed sources and written about home improvement, interior design and related business trends. She earned a B.A. in Journalism from the University of Nevada, Las Vegas. Her full bio and clips can be viewed at

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