How Much Grout Do I Need? What professionals say

Grout is one of those things you don’t think about until you need it. And when you do, you realize you have no idea how much of it you should use for your repair or renovation project. If this sounds familiar, you’ve come to the right place.

You can figure out how much grout you need using an online grout calculator. The tool will ask for data such as tile size, spacer dimensions, and the total area to be tiled. Then, it will calculate the total amount of grout required in kg or pounds.

This article dives deep into the mathematics of grout estimation so you can work it out even if you’re unable to use a grout calculator for any reason. Also, you’ll have a better understanding of the process and figure out whether the calculator you’re using is accurate.

What Is Tile Grout, and What Does It Do in Construction?

Grout is a construction paste used to seal the spaces between tiles. It’s typically made of Portland cement, water, sand, and colorants. 

Grout has three main purposes:

  • To physically support the tile
  • To waterproof the spaces between the tile
  • To provide a clean, finished look

In case you’re wondering why you need to leave spaces between the tiles, it’s because tiles tend to expand and contract due to temperature changes. Otherwise, if the space is too small or large, the tiles may suffer damage such as cracks. 

How To Calculate the Amount of Grout You Need

Calculating the amount of grout you need is relatively simple.

Here are the steps to manually calculate the amount of grout you need.

  • Step 1: Add the tile width (mm) to the tile height (mm) and label this number A.
  • Step 2: Multiply the size of spacers (mm) by tile thickness(mm) and label the result as B.
  • Step 3: Multiply A, B, and 1.2 to get C. The reason for the 1.2 multiplier is that it’s the coverage ratio of most grouts.
  • Step 4: Multiply the tile width (mm) by the tile height (MM) to get D.
  • Step 5 Divide C by D to get E. E is the amount of grout you’ll need in kg per meter squared.
  • Step 6: Multiply E by the total area being tiled (meter squared) to get the total grout required (kg).
  • Step 7: Convert the answer in Step 6 from kg to pounds. Of course, you should only do this if you’re from a country that uses the imperial system.

I get it. This formula can be a little confusing, so let’s break it down with an example.

Suppose you are tiling a kitchen backsplash that’s 2 feet wide and 4 feet long. The tiles you’ve chosen are 8 mm thick with 3 mm spacers. 

To calculate the amount of grout you need, follow these steps:

       A = 8 (tile width in mm) + 4 (tile height in mm) = 12

       B = 3 (spacer size in mm) x 8 (tile thickness in mm) = 24

       C = 12 x 24 x 1.2 = 288

       D = 8 (tile width in mm) x 4(tile height in mm) = 32

       E = 288 / 32 = 9 (This is the amount of grout you’ll need in kg per meter squared)

       F = 9 x 2 (total area being tiled in meter squared) = 18 (total grout required in kg)

       G = Convert 18 kg to 40 pounds (1 kg = 2.2 lbs)

So there you have it! You’ll need 40 pounds of grout to tile your kitchen backsplash.

How To Use a Grout Calculator

If all of this math is giving you a headache, don’t worry. You can use a grout calculator to do the work for you.

There are many grout calculators available online. All you need to do is enter the dimensions of your tile and space, hit “enter” (or the equivalent in the calculator you’re using), and the calculator will do the rest.

I particularly like the Omni calculator because it’s very user-friendly. Just enter the width and height of your tile, spacer size, and the total area being tiled. The calculator will give you the amount of grout you need in pounds, eliminating the need for manual conversions.

Types of Grout and When To Use Them

Now that you know how to calculate the grout you need, it’s time to learn about the different types of grout. Grout comes in many different colors, textures, and formulas. The best type of grout to use depends on your project.

The three most common types of grout are as follows.

● Cement-Based Grout

Cement-based grout is the most common type of grout. It has Portland cement as its base, albeit thinner. That means it can flow better into cracks and crevices and is perfect for most tile jobs.

The issue with cement-based grout is that it’s susceptible to staining. It’s also not as strong as epoxy grout, so it may not be the best choice for areas with a lot of traffic or moisture like the bathroom or kitchen.

● Furan Resin Grout

Furan resin grout is similar to cement-based grout but is made with furan resin instead of Portland cement. This grout is stronger and more resistant to staining than cement-based grout.

However, furan resin grout is also more challenging to work with because it sets quickly. For this reason, it’s best used by experienced tile setters.

● Epoxy Grout

Epoxy grout is the strongest type of grout. It’s made with a two-part epoxy resin that gives it superior strength and durability. This grout is perfect for areas like kitchens and bathrooms because it’s resistant to staining and won’t crack or crumble over time. 

The downside to epoxy grout is that it’s the most difficult type of grout to work with on this list. It also tends to be the most expensive.

Over to You

Maybe you’ve been putting off tiling your kitchen backsplash because you were intimidated by the grout selection process. But now that you know more about grout, you’ll (hopefully) feel confident enough to tackle that renovation project. Just take your time, don’t be afraid to use a little elbow grease, and you’ll have beautiful results.

When choosing a type of grout, always consult with a professional tile setter or your local hardware store. Chances are they can recommend the best kind of grout for your project.

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