What's the Difference Between Grout and Mortar?

Construction terminology can and will get confusing. It takes some time to learn about the metric ton of materials, equipment, and tools, so don’t feel too frustrated when you can’t tell the difference between grout and mortar. Sure, both are used in construction as adhesives and gap fillers, and while they do accomplish relatively similar tasks, they are by no means the same.

If you’re getting ready for a DIY remodel or construction project, it’s important to know the difference between grout and mortar lest you make a mistake that costs you more time and money in repairs. Both grout and mortar are widely used in a variety of construction projects, so knowing how they function can help you decide on which one to utilize. 

How Grout and Mortar Are Similar

The Similarities of Mortar and Grout

Before we can compare the differences between grout and mortar, it can be beneficial to first understand their commonalities. The first similarity comes in how the two are used. They are both construction adhesive compounds, as they are used to either adhere two materials together or to fill in gaps.

Both are cement-based, meaning they harden as they dry, which comes in handy for construction tasks such as putting together a brick wall or plugging up the voids between tiles. In fact, the main difference between the two materials is the amount of water that is mixed into them. Grout, for example, typically has much more water than mortar, though the base ingredients of the two are pretty much the same.

Grout

What Is Grout and What Does It Do?

Grout is a type of filler that is used to close voids between tiles, bricks, and other construction materials. It’s not so much a binding agent as it is used to plug up holes and crevices or strengthen construction bonds and joints. One of the most common uses for grout is smearing it over tiles and filling in the gaps between them. This not only fills up these crevices, preventing moisture and dirt buildup, but it also helps keep the tiles in place. Additionally, grout blocks out mold and mildew from developing, keeping the tiled surfaces spick and spam.

Due to its greater water content, grout is significantly more liquid making it even more convenient for filling in holes and gaps. It’s easy to smear grout over surfaces with a lot of gaps and have it seep into the deeper pockets that more solid binders, like cement or mortar, cannot as they are too stiff.

What Can Grout Be Used for?

You will find grout commonly used on tiled floors and walls. Those white or grey lines you see between tiles are hardened grout. It is smeared over the tiles using a rubber float after the tiles have been installed. This keeps the gaps between the tiles closed off to any dirt and moisture, and the grout acts as additional structural support to keep the tiles in place.

Grout is used in foundations where it fills voids and gaps left behind by the rigid construction material and the less liquid binders. This helps with the structural integrity of the foundation joints and increases their longevity. Depending on the kind of project you’re working on, you’ll be using one of the many grout varieties out there. There’s masonry grout which is used to fill in empty spaces in other construction materials, such as concrete blocks. This extra filling can help with structural integrity and even be used as sound insulation to drown out the outside noise. There is also brick grout or even commonly referred to as fireplace grout, which is used to line the mortar on brick walls and fireplaces. This filler evens out the mortar between the bricks of fireplaces and walls, making their exterior more attractive.

Durability and Maintenance

How to Maintain Your Grout

Once it dries and sets completely, grout is very durable. However, it is not invulnerable and will slowly lose its strength over time. This is especially true with tile grout, which is regularly exposed to water and steam that decrease its strength. As a result of water damage, grout can crumble and break apart, creating little holes between the tiles. Grout maintenance involves cleaning it with warm water and a brush with stiff bristles. For a deeper wash, there are specialized cleaning products that clean stains and brighten the grout to look good as new.

For a more proactive approach, you can also try one of the many grout sealers on the market. Sealers are a special compound that covers the grout and protects it from water, heat, and other kinds of damage. Some grout sealers may also give it a bright glow if this is what you’re looking for in your tiled surface. With regular cleaning and maintenance, as well as using a good grout sealer, your grout can last you up to 15 years before needing replacement. 

Mortar

What Is Mortar and What Makes It So Useful In Construction

By mixing water, cement, sand, and a bit of limestone you get mortar, one of the most versatile binders in construction. This concoction creates a material that is spreadable and malleable when wet, but when it dries, it turns into one of the most durable adhesives your construction project could ask for. Mortar may not be as strong as its cement-based cousin concrete when combined with other construction materials, but it can really get the job done in terms of durability. 

What Can Mortar Be Used for?

The main use for masonry is helping to adhere bricks to one another in the construction of walls, columns, and other structures. Bricks on their own are strong, but require something to hold them together. This “something” is mortar, which is smeared over the bricks, with another layer of bricks adhered to it. At first, when the mortar is still wet, the structure is not all that strong. But once the mortar sets and the bricks are all stuck together, you have yourself a sturdy structure.

Some mortar variants can also be used to strengthen joints and even fill in gaps. Much like grout, these have to be slightly more liquid types of mortar that can seep into these deeper crevices and plug up holes. This not only further enhances the structural integrity of your construction project but also creates water-tightness that protects it from moisture damage. 

Durability and Maintenance

How Strong Mortar Is and How to Maintain It

Mortar is quite durable when it hardens. Look around your neighborhood and find all the various structures and construction projects that utilize mortar and see for yourself how sturdy they are. You will find walls and chimneys that are centuries old, yet the mortar still holds up quite well. Obviously, this is not always the case, as poor mortar or bad craftsmanship can lead to weaker structural integrity, but regardless, using mortar is a time and tested method of binding various kinds of construction materials.

While mortar is used to waterproof walls and surfaces, water damage is still going to get the best of it if you leave your mortar without any sealers. Water can seep into the cracks of the mortar. During the winter, when these little drops freeze, they expand. When this happens, the ice pushes the mortar and causes it to crack, which in turn allows more water to seep in and the cycle continues. Using a mortar sealer, you can prevent water or any other corrosive substance from making its way into the inner layers of the bricks. Other aspects of mortar maintenance involve getting rid of any plant growths inside the mortar layers, restoring its color by painting it with special caulk, and once in a while refreshing the mortar in areas where it has deteriorated.