Does A Bricklayer Lay Bricks Frog Up Or Frog Down?
When laying bricks, it is important to ensure that you do so in the correct manner in order to achieve a stable and sturdy structure. Some bricks have what is known as a frog; no, we aren’t talking about a small, green amphibian. We are referring to the indentation found in some, but not all bricks.
But if you find yourself building a brick wall or other structure with frogged bricks, you might be wondering if a bricklayer lays bricks frog up or frog down.
It is widely accepted that bricks with a frog should be laid with the frog facing upwards. This is because the frog must be filled with mortar in order to avoid problems with structure, acoustics and insulation. If a brick is double frogged then it is common practice to lay the brick so that the deeper frog is facing upwards.
The reason that some bricks have frogs is two-fold. This indentation is where the manufacturer will place its stamp but this isn’t the main reason that a frog might be included.
A frog is used to reduce how much material is needed to make the brick. Doing this makes it easier to remove the brick from the form. A frog may also improve how easily the heat can reach the centre when it is in the kiln, therefore creating a stronger block from the inside out. With this shape, more mortar can be included since the frog must be filled and this creates a much stronger bond between bricks, resulting in a stronger overall structure.
Why Is It Called A Frog In A Brick?
It is believed that frogging a brick dates back as far as the ancient Egyptian times so how it got its name has obviously become something like Chinese whispers over the centuries. However, there is a viable suggestion that the term frog comes from a Dutch word kikker. This word refers to a kicker which is put at the base of a wooden box that would have been used to make bricks. This kicker forced the material outwards as the brick was being made. Makes sense, right?
So, back to the Egyptians; they invented this feature of the brick when making Nile clay bricks, into which they formed a hollow. The reason for this hollow was so that they could put a live animal inside the bricks before using it to build. There were many different animals used in this process and the theory as to why the Egyptians did this is vague. Although a lot of experts will tell you that it was believed that in the afterlife, the animals would help the Pharaoh. In any case, one of the most common animals used was the frog since it was believed to be a symbol of fertility.
Another theory about the reason behind the name is that, in the early days of making bricks, what is now known as a frog looked very similar to the indentation found on a horse’s hoof. While this information doesn’t make a lot of sense on its own, when you learn that this indentation is known as a frog, all suddenly becomes clear!
There are also suggestions that the word frog can mean to fasten something. This is usually used when referring to the loop on a belt or similar type of fastening. However, since the frog of a brick is filled with mortar to ‘fasten’ or hold it to the neighbouring brick, it doesn’t seem too much of a stretch of the imagination to believe that this is why it has this name. Of course, we also have to consider the fact that the frog of the brick simply looks very similar to a crouching frog. It’s often the most simple explanations that make the most sense!
Why Frog Is Provided In Bricks
One of the main reasons that bricks have a frog is so that the manufacturer can use less material when creating the bricks. This allows them to make more bricks out of one batch of clay; it makes pretty good business sense, if you ask us. There’s also something of a suggestion that this frugality is where the frog got its name (as a bonus fact!)
Using less material might help to save money but the way that it is done does not affect the structural integrity of the brick so you still get something that is equally as strong as a non-frogged brick.
Moreover, during the manufacturing process, it can be difficult to remove a non-frogged brick from the form. This indentation makes it simpler and therefore easier for the manufacturer.
You’ll also consider that, during the firing and drying process, including a frog vastly reduces how long this takes. Heat is much more easily able to get to the centre of the brick and when it comes to drying, this structure means air can better circulate around it.
What Is The Correct Way To Lay A Brick?
Frogged bricks are excellent for structures that need to have very secure and solid bonds. The frog must be filled with mortar and this will allow it to bond more firmly with the neighbouring brick. So, when laying frogged bricks, you should always have the frog facing upwards for the simple reason that this makes it easier to fill with mortar.
In some cases, bricks may have two frogs. When this happens, you will need to ensure that the deeper frog is facing upwards. You’ll still need to fill the lower frog with mortar but doing this with a deeper one will mean that some falls out and things get much more fiddly than they need to be. If mortar is not added in the frog, then the wall will not be as solid and there may be thermal or acoustic problems down the line.
When filling bricks frog down, it is best to load your trowel with an adequate amount of mortar and lower the brick onto it before putting it into position.
Related Article: How Do Bricklayers Take Care Of Their Hands?
Conclusion
Not all bricks have frogs but those that do must be laid with the frog facing upwards as this allows the bricklayer to fill the gap with mortar. Failing to do this will have repercussions in terms of the bond between bricks and the strength of the wall. Thermal issues and problems with sound transmission may also arise when bricks are placed frog down and not filled.