DIY Renovation Project Guidelines: Should I Use Grout or Caulk?

Pin it button big

I learned a lot by working on my first bathroom remodel. One of biggest was where and when to use grout versus caulk. Grouting and caulking, although very similar, serve different purposes and shouldn't be substituted for one another. Follow these guidelines and get it right every time.

Pin it button big

Let's take a look at the differences and purpose for each joint sealant:

Grout

According to Wikipedia, Grout is generally a mixture of water, cement, sand, often color tint, and sometimes fine gravel (if it is being used to fill the cores of concrete blocks). It is applied as a thick emulsion and hardens over time, much like its close relative mortar.

  • Cement based grout without any latex added to it means it's porous and not waterproof.
  • Grout should be used in between joints of the same plane.
  • The space between tiles should be small enough for unsanded grout or large enough for sanded grout.
  • Grout won't stick to face of tiles. It needs a crevice to hold into.
  • Epoxy grout is strong enough to withstand structural movement and can be use in corners, but is not as flexible as caulk.
  • Grout helps prevent the edges of tiles from chipping or cracking.
  • Grout helps fill voids and keep debris out of spaces in between tiles.
  • Application method: Scrape is all over your tile and jam it into crevices. Then wipe off excess with a sponge. (It's a very messy process).

Caulk

Defined by Dictionary.com, Caulk is the material used to fill or close seams or crevices in order to make watertight, airtight, etc.

  • Caulk is silicone, acrylic, or latex based, which is flexible and can help absorb movement, whereas grout can crack.
  • Caulk is used to waterproof joints for space like bath tubs, showers, windows etc.
  • Caulk is strong enough to adhere to tile surfaces without crevices.
  • Caulk is flexible enough to adhere to two different materials such as glass and tile.
  • Caulk may shrink or dry out over time, which is why it shouldn't be used in large installations or as a replacement for grout.
  • Application method: Use a caulking gun to carefully and tediously lay a bead along nooks and corners.

Grout and caulk can be purchased in the same color and with or without added sand for a seamless installation. Caulk is usually applied to areas where movements occur, like corners and a change in materials. You may think this movement would only occur during earthquakes (and then, you'd have more to worry about than a crack in your grout line), but movements occur all time even if you don't feel them. Wood shrinks and expands with out us noticing. If we bump into our glass showers or our vanity, it's likely to cause some vibration. Caulk is used for two very important reasons in the bathroom: 1. To prevent cracking by absorbing movement along two different planes/materials. 2. To waterproof/seal areas/corners that are susceptible to mildew and mold damage.

Have a tiling project in mind? Visit our "How To" tutorials on Tiling, Grouting, and Caulking.

(Image credits: June Bhongjan)