Why do house bricks have holes in them?

Factual Questions
1

Pavers are solid. Construction bricks have two or sometimes three holes. I’ve seen old time bricks made on tv reno shows. Wood forms with red clay packed in. Then placed in a kiln and fired. But can’t recall them making the holes.

years ago I saw a mason working on a house. It looked like he was threading a steel band through the bricks and nailing it to the wall. I was watching for just a few minutes from a distance and never saw it up close. Anyone familiar with that in brick laying?

So are the holes designed for that steel band? Or is that just something masons did later?

2

This website says, “A defining characteristic of extruded brick is the core holes running through the bed. Despite rumors, core holes are there only to lighten the brick and aid in drying the clay before firing and does not assist or take away from the structural strength of the brick.”

The Wikipedia article on brick says something similar.

3

the holes allow the bricks to dry faster, use less material, weigh less, provide a key for mortar to lock the bricks together.

the steel bands are called brick ties. the bricks aren’t tight to the building (in wood structures) and this helps secure the brick veneer to the building. these can lay straight on the brick or mortar into a hole.

4

A quick Googling of “Why do house bricks have holes in them?” reveals that the holes save material and weight, provide for quicker and more even firing, and provide lateral stability since mortar squishes into them. Rebar can be put in the holes for added strength.

5

I thought saving material was just a myth. Seems like making the holes would cost more time than saving a spoonful of clay.

<shrug> I guess it is worth it after all.

My uncle had his chimney pull away from the house. It eventually fell. The ground there cracks and shifts every summer. One of his neighbors had his chimney fall and got it rebuilt. It fell again within five years.

6

The bricks aren’t shaped by hand. There’s not a guy with a tablespoon or brace and bit who makes the holes. The wet clay is extruded (with the holes already there), sliced every four inches, then dried.

7

In the movie “My Bodyguard” (a long time ago…) the kid in pottery class is making a big round blob with lines on it. The other kid asks him, “waht are you making?”. He replies “a grenade”.

A while later in the movie, the tacher announces - “unfortunately one of the pieces exploded in the kiln and all your piecs were ruined.”

Obviously, they can make bricks without the moisture being trapped inside steaming (Tera cotta is more pourous?) and bursting the bricks - but holes in the brick reduce the size of the clay lump. I’ve seen both solid and holy bricks.

8

Brick (and masonry in general) construction is traditionally used much more in Spain and Latin-American countries, as well as other Mediterranean and Arab countries, than in northern countries.

While it is rare today to use brick for load bearing walls it was quite common in the past. Nowadays most often a building will have a concrete (less often steel) structure which does all the load bearing, then the outside walls are composed of an outside wall of solid brick, an insulation gap and then an inside wall of double hollow brick for a total thickness of 10 to 12 inches. Interior walls and partitions will be hollow brick and plaster.

Still, building with concrete and brick makes for a much more solid building than American frame homes which are easily destroyed by tornados as we often see in the news. It is possible but I do not know that frame homes may better be able to withstand earthquakes.

I do not much see the point of using brick cladding on a lumber frame building. I would rather have a stronger structure.

Solid brick without any kind of perforations can be used as pavers or similar uses but are not normally used any more in building where perforated bricks are far superior.

Perforations are not about saving material at all as the perforations will mostly be filled with mortar which is more expensive.

“Solid, perforated” brick is normally used for load-bearing walls or exterior walls which need to be very solid even if not load-bearing. The perforations run vertically as the brick is laid and the purpose of the perforations is to allow the mortar to penetrate into them so the mortar is placed on the lower brick and then the next brick is laid and tapped so the mortar runs into the perforations until the thickness of the mortar between bricks is uniform. The mortar running into the perforations results in a better and more solid bind between mortar and bricks and a more solid and airtight wall as a result. The main purpose of the perforations is to interlock the bricks with the mortar.

Also the perforations make the brick better withstand the stress of firing. If a crack develops it will be between two adjancent perforations and the brick is still good. A crack in a solid brick can easily mean a broken, unusable brick.

Solid, perforated bricks can be “rough” if they will not be visible in the finished work and will be covered with plaster or other finish. These bricks have a rough finish so that the finishing plaster will adhere to them.

If they will be visible when the wall is finished then they have a smooth finish and are called “facing” bricks.

Most of the time cement mortar is used with these bricks as it is the strongest. These walls have very little air voids left and are mostly solid with brick and mortar. Depending on the thickness and bearing capacity needed the brickwork (i.e.: the wall) can be thicker than just one brick.

Solid perforated bricks are mostly extruded now but they were also traditionally made in presses.

Solid, perforated, rough.
Solid, perforated, facing (smooth finish).

Then we have “hollow” bricks where the perforations run horizontally when laid and are not load-bearing. They are used for interior walls and partitions generally with plaster, not cement. They are always “rough” and need to be covered with some sort of finish, plaster, tile, etc. These walls have a lot of air voids and are not as strong as those made from solid brick. I have not seen these hollow bricks used in the USA where drywall is used instead (or lath and plaster before that).

Hollow bricks can be single, double or triple, depending on the number of perforations.

This page has photos of solid and hollow bricks.

Youtube video showing a wall being built with rough brick. You can skip to about minute 6:00

9

Cost, speed and ease of repair are the big 3 I can think of. I mean, in most parts of the country, we’re not looking at super-severe snowfall, and the actual risk of tornadoes is pretty tiny when looking at a single house, so why overbuild with a brick veneer over a concrete or steel structure? There’s no requirement for greater strength, and it would cost a lot more and be more trouble (i.e. not easily remodelable) to have a structure with load-bearing masonry walls and internal structure.

The brick veneer is totally an aesthetic thing- there are houses that are totally covered with siding.

There are also bricks common here in Texas, mostly cheap, soft Mexican ones used in the 1960s that don’t have the holes in them- I suspect they were made in molds instead of extruded and fired.

10

But in those countries where brick is used, it is not “a brick veneer over a concrete or steel structure”. The structure is cage-like and the brick fills the spaces in between. At least in modern construction, my house is built “the old fashioned way” and the load-bearing walls are about half a meter thick, but there is no concrete or steel structure.

11

Not entirely. It can be a matter of economics. A brick wall will stand up to weather better than just about any siding. Repointing a few bricks every fifty years, or so, is a lot cheaper than re-siding a house every thirty to forty years or repainting it every decade. (And when your kid is playing catch with himself, there are no unsightly ball scuffs as there are on wood or dents as there are in the aluminum or vinyl siding.)

While attaching the bricks better would have improved the situation, this was more likely due to a failure to begin the bricks on a solid, frost proof foundation. If the bricks start at the ground and go up, they are more subject to frost heave or settling than if they are as firmly planted as the rest of the walls.

12

brick veneer around a lumber frame building can be a lifetime maintenance free exterior. chimneys will likely need work.

if a location has clay near then there might be solid brick buildings as Nava stated.