Mortar Joint Thickness: How Big Is A Mortar Joint?
The mortar joint is one of the most common building materials used in construction. It is usually made from brick or concrete. It consists of two pieces of mortar joined together with a small gap between them.
It is not uncommon to see mortar joints in old buildings. They are often found at the corners of walls and other places where it is necessary to have a certain amount of space between two adjacent walls. Mortar joints can also be used in new construction to create a decorative effect.
The thickness of a mortar joint is usually about one or two inches but may be smaller or larger depending on the situation.
The mortar joint has a number of functions. It acts as a filler for an area between two walls where the structures meet. In older buildings, it can help provide structural support to the building.
Mortar is usually made from a mixture of sand, water, and cement. When the mixture dries, it hardens into a solid mass that is sturdy enough to hold up the weight of a wall or roof. The gap between the two pieces of mortar prevents the walls from rubbing against each other and weakening or destroying them. The larger the gap, the more strength the walls receive. For this reason, mortar is a very important part of any wall. It is usually the first thing that begins to deteriorate as well.
As the years pass, mortar joints often get larger cracks in them.
Without a proper sized mortar joint, the walls could begin to crumble and weaken. In new buildings, the width of the gap is usually standardized according to building code requirements. The longer a building stands, the larger the cracks become.
Rain and snow get in the cracks and eventually cause the whole wall or structure to fall apart. Over time, mortar joints generally get larger. If a wall begins to crack, the gap can be filled in with more mortar. Old buildings do not usually have this luxury and require specialized skills and tools in order to repair them.
In the past, masons used trowels to spread mortar evenly in the joint.
The spread was usually less than one inch and allowed the two pieces of masonry to touch at certain points.
The larger the mortar gap is, the stronger the wall is and the longer it will last. A smaller gap will decrease its strength. The width of the gap can also be standardized or even customized to fit the building code in your city.
Widening the gap can be beneficial in some situations. It allows easier access for repairs, for instance. The disadvantage is that it decreases the wall’s strength.
If a wall needs to be thicker, concrete “re-enforcing bars” (or “re-bars”) can be embedded into it to provide extra reinforcement. This is usually done in the foundation before the wall is even built. The wall is essentially “floating” on these bars, which are then firmly anchored to a concrete foundation. This method is usually only used for garage walls and other areas that don’t bear as much weight.
A gap is needed between the two pieces of masonry for several reasons. If the two pieces are touching, there is no room for expansion. As the temperature rises and falls, the material will shift slightly.
If there is no room for this to happen, the wall could be damaged. This is especially true with brick structures where the mortar acts as “glue” that holds the bricks together. If the “glue” dries out and shrinks, the structure could fall apart.
A properly sized and placed mortar joint is an essential part of any wall or structure. The gap provides several benefits, including flexibility and strength. It also allows repairs to be made easily and quickly.
A poorly sized or placed mortar joint could cause major problems with a wall’s structure.
In some cases, it can be beneficial to reduce the size of a gap and increase its strength. This can be done by using a “gap filler.” There are several on the market that can be used.
They are typically made from a foam-like material or cork. These materials can compress under pressure and prevent the wall from shifting. They are most often used in the joints of pre-cast concrete panels. These panels are usually held together by steel rods and expanded metal cages. The panels are fairly rigid but, without a gap filler, they can’t withstand much force. Using a gap filler will increase the strength of the joint and allow it to withstand much more pressure.
Types of Masonry Joints
There are several different joints used in masonry. Each has its own advantages and disadvantages. Choosing which one to use depends on several factors, including the material, the size of the wall or structure and its purpose.
The most common joints are described below.
Brick on Bond
The brick on bond is the simplest joint there is. It’s done by simply placing bricks next to each other, with the ends perfectly aligned. This creates a straight edge that is often attractive to the eye and easy to work with.
It’s mostly used on load-bearing walls or other parts of a structure that need to be vertical.
Brick on Header
A brick on header is another common joint. It’s done by placing the bricks on top of a single row of bricks laid on their ends. Again, the joints between the bricks are aligned perfectly.
This joint is fairly strong and is used on most load-bearing parts of a wall. It’s fairly easy to work with and creates a very sturdy structure.
Stretcher on Bond
A stretcher on bond is done by placing the bricks with their long sides face up. They are laid next to each other with the joints aligned. This joint is also fairly strong.
It’s mostly used on the non-load bearing portions of walls. One disadvantage of this type of joint is that it can sometimes draw water toward it. This can be a problem in cold or wet climates, causing the wall to weaken and even fall apart over time.
A header is simply a brick with the long side facing up instead of down. It’s laid over two rows of stretchers. A header on a bond is done by placing a header brick on top of two bricks laid on their ends.
It can also be done by placing a header brick on two bricks laid on their long sides.
A header can be used to create an arched effect, especially when placed on two small bricks laid on their long sides. It can also be used to span wider gaps than any other type of brick.
The disadvantage of headers is that they have a much smaller surface area than other bricks. This can cause them to break if they are not laid in a row that is properly supported on both sides.
The broken bond is fairly simple. Instead of laying all the bricks in a row so that the joints are aligned, they are laid alternating with their joints. For example, instead of having two rows of brick with aligned joints, you might have a row of headers, a row of stretchers, another row of headers and then another row of stretchers.
This creates a fairly strong wall, but it’s also fairly easy to work with. This type of joint is often used in the concrete blocks that form the foundation of many homes.
The random bond is similar to the broken bond. Instead of alternating the joints of the bricks, they are aligned in a seemingly random pattern. This creates an interesting visual effect.
It’s fairly easy to lay and provides decent strength, but isn’t quite as strong as some of the other joints.
The bonding pattern is the same as the random bond, but with headers added. It’s fairly easy to lay and provides good strength. One disadvantage is that it can be difficult to work with on a large scale project.
It’s also not as strong as some of the other joints.
The header Bond is done by placing bricks on their ends in a alternating pattern similar to broken bond. It creates a fairly strong wall, but it can be difficult to work with and not as strong as some of the other joints.
The common bond is the most popular. It consists of laying the bricks in a alternating row pattern so that they all have aligned joints. It’s fairly easy to work with and is quite strong.
This is the most common pattern for bricks in most homes.
The bed joint is a simple pattern that is fairly easy to work with. It consists of an alternating row of stretchers and headers. This type of bond is fairly weak and not often used in walls.
It is mostly used in floors, fireplace hearths, and similar structures.
The English bond is fairly common in England, but less common in other places. It consists of three rows of stretchers with a row of headers at the top and bottom of the wall. It’s fairly easy to lay, but it’s not very strong.
This type of bond is quite popular in walls that aren’t bearing any weight such as in garden walls.
The Flemish Bond is a strong and fairly easy to lay pattern. It consists of two rows of stretchers and a row of headers. Then this pattern is reversed with two rows of headers and a row of stretchers.
It can be laid in such a way that the headers all begin and end on a corner to help strengthen it.
The Random bond creates a very strong wall. It consists of laying the bricks in seemingly a random pattern so that the joints don’t align row by row. It’s a fairly difficult pattern to lay, but it’s quite strong.
This pattern is used in the construction of some of the older buildings in cities such as New York.
The Running bond is fairly easy to lay and creates a strong wall. It consists of laying bricks in a staggered pattern so that they form vertical rows that run from one end of the wall to the other. It uses a lot of bricks, but it’s quite strong and very popular.
The English Bond is a fairly simple pattern that’s easy to lay. It consists of a layer of stretchers, then layer of headers and then another layer of stretchers. It’s fairly strong, but not as strong as the more complex patterns.
The stretcher is the most basic brick that can be laid. It’s a simple square block that’s laid with the length running up and down the wall.
Now that you have your materials it’s time to start building. You’ve already got the foundation laid and the walls built up a few courses high. You need to decide what type of bond you’re going to use because that will determine how you lay the bricks.
Building something is a group effort. You and your team will be building a wall together in real life. You’ll also be building a wall together in a simulation.
In both instances, whether it’s real life or a simulation, the stronger and better the foundation is, the better the finished structure will be.
A group of four is gathered at a table with pencils, papers, an envelope, and bricks. They are told the following:
The group is divided into two pairs of students. Each pair of students are given ten bricks to build with. They are told to use the bricks to build a structure of some sort.
They have twenty minutes to build and their structure must be at least three bricks high. The groups are then left alone to build. After twenty minutes, they are told the following:
What types of patterns did you see used and in what order?
The groups used a total of 6 different types of bond in their creations.
Sources & references used in this article:
- Inelastic behavior of sand-lime mortar joint masonry arches (BT Rosson, K Søyland, TE Boothby – Engineering structures, 1998 – Elsevier)
- Homogeneity and strength of mortar joints in Pearl-Chain Bridges (MSM Lund, M Arvidsson, KK Hansen – Fib Symposium 2015: Concrete …, 2015 – core.ac.uk)
- Experimental Study of Mortar Joint Bond Strength of Autoclaved Aerated Concrete Masonry Prism (F Ma’arif, S Widodo – Proceeding of Annual South East Asian …, 2013 – eprints.uny.ac.id)
- Steel corrosion induced by chloride or carbonation in mortar with bending cracks or joints (S Miyazato, N Otsuki – Journal of Advanced Concrete Technology, 2010 – jstage.jst.go.jp)