Oh my! A crack in my wall, what is going on? Don’t look no further, in this blog we give you answers on the cause of the most common cracks. Also we will tell you if it’s bad or not. We will explain it nice and easy, so everyone can understand.
A horizontal crack in the plasterwork on the inside
Cracks in the plasterwork are in most cases not that bad because they are not ‘constructive’ (plaster doesn’t need to keep the house together) and because they are easy to fix. Ok, that makes it easier. The cause of cracks is in most cases the shrinking of material. You see this a lot with renovated houses and even with new-build houses.
A vertical crack in the stucco inside the house cause 1
These are usually caused by the use of different materials. Every material expands (by warmth) and shrinks (by cold). How much they do that is what we call expansion coefficient. When 2 or more used materials have a different expansion coefficient, then these kinds of cracks can arise. Fixing the crack is pretty simple. The plasterer can help you with this. They scrape the crack out, place a net over the crack and plaster it nice and shut. When the plaster is dry, you can paint the (preferably entire) wall. Pay attention: it can be that a crack will come back a little bit at some point. These cracks are in most cases not that bad, because they are not ‘constructive’ (they don’t have to keep the house together) and because they are easily fixable.
A vertical crack in the plaster inside cause 2
Another cause of a vertical crack in the plaster on the inside can be by setting. Imagine that you are standing on the beach with bare feet. Someone runs close by and after that you feel your feet moving in the sand. That’s called ‘setting’.
With your house, setting can have many causes. You may have a foundation type that is similar to the ‘barefeet on the beach’ (this is foundation that is on sand, also called foundation “on steel”). This type of foundation can find his ‘spot’ after a certain period (in other words: lower a little bit.) That’s not bad.
It’s also possible that there is placed an extension on the house. When this extension gets a bit of setting, it can pull the house, and because of that small vertical cracks can come in the wall. These cracks are in most cases not that bad, because they are not ‘constructive’ (they don’t have to keep the house together) and because they are easily fixable.
Vertical cracks in your inside walls
Often these cracks occur due to uneven loading on the interior wall. The important thing is what’s happening with the floor on above. What’s put there that is to heavy in weight? Is there some concrete somewhere, or are there heavy closets or something else? This can cause these cracks. It’s also possible that the cause is vibrations from above. No worries, these cracks are in most cases harmless. A plasterer can get rid of these easy. If you are handy you can do it yourself with flexible paintable kit.
Cracks in the ceiling of the bedroom/bedroomfloor
These are one of the most common cracks we see in old homes. They appear because there is still old stucco-on-reed at the ceiling of the bedroomfloor. In this ceiling there is reed with metalwires and these metalwires push on the plaster. The old atticfloors were not build to live on it. Because this has become commonplace over the years, the ballast in the attic floor is higher than originally envisioned. This extra ballast ensures that the metal wire then pushes through into the piecework. This creates the cracks you see. These cracks are not constructive and not bad. You can (if you want to leave the ceiling intact) apply fiberglass wallpaper and paint it. Because of this you mask the cracks.
Cracks in the concrete ceiling or floor
These are cracks you have to take seriously. Cracks in a concrete ceiling or concrete floor can tell you that there are problems with the metal in the concrete floor. It’s also possible that it’s just to heavy lifting. Especially in the middle of the floor/ceiling on the downside must be looked in to. This is because the greatest “bending moment” in the floor occurs in the middle of the span. This results in isues with the tention of the floor.
Dangerous situations in concrete floor appear when:
-there is not enough concrete steel in the floor or
-when the concrete steel is not attached properly or
-when the concrete steel is rusted as cause of the wrong material in the concrete (concrete rot) or
-if the floor has to bear a heavier load than it is designed for
The urgent advice when you find such cracks: immediately have a construction specialist carry out further investigations.
A vertical crack on the inside of the window frame
These cracks are caused by setting (see the explanation earlier in this blog). When the crack is only visible on the inside and on the outside you don’t see anything, then these cracks are not that bad in most cases. There came a natural ‘dilatation’. Short explanation about the word ‘dilatation’: with walls it means that they cannot be made out of 1 piece only. Pay attention with the facade of a new-build home. You will see that within every other meter from top to bottom there is a small space in between. This is necassary or else the wall will crack (dilatate) by the setting of the material. In many old houses this is missing, therefor a crack can appear that this ‘dilatation’ creates (in a natural way). So, a natural dilatation.
Diagonal cracks in the outside facade
Are there more than 1 diagnol cracks in the facade? Then these are the cracks to worry about. These cracks can tell you that there is ground subsidence or problems with the foundation. Often these cracks are going towards windows and facade openings. Immediately hire a architectural specialist to do more research.
Horizontal cracks in the outside facade/walls
Do you see horizontal cracks in the outside wall and are there also 1 or more diagnol cracks, then this can tell you about problems with the foundation. Another cause can be splash forces from the hood/roof of the house. In simple words about the term ‘splash forces’: this has to do with the weight of the roof that leans on the facade. If something is not right here structurally, horizontal cracks can appear under the hood/roof. Sometimes you recognize it extra good by bricks that come out of the wall on the outside. In both cases it’s definitely bad news. Hire an architectural specialist to do more research.
Vertical cracks in the outside wall
One or more vertical cracks in the outer wall may indicate a ‘thermal change in the length of the outer wall’. Don’t worry, we’ll explain what this means. Your outer wall expands and contracts due to temperature changes. When it’s hot, your outer wall lengthens, when it gets cold, it shrinks and shortens. It’s unbelievable, but true. As you hopefully understand, the total weight (mass) of an outer wall is enormous. A wall should not be too long in one piece. Gaps must be placed in the wall so that the wall has sufficient freedom of movement when it expands or contracts. In many old houses you see that gaps/dilations in the outer wall are missing. After a few weeks of warm weather, the wall has expanded considerably and has therefore become longer. If it gets cold quickly, the wall will shrink quickly. This is called “thermal length change” and this “shrinkage of the wall” produces enormous “tensile forces”. These tensile forces can result in a straight vertical crack in the outer wall. One advantage of such a crack is, that there is now a gap in the wall that they really should have put in when they built your house. It originated ‘naturally’ and is therefore called a ‘natural dilation’. In principle, such a crack is harmless. The point is just that it can get bigger over time. This is because crumbling pieces of masonry can remain in the crack. These can prevent the wall from closing again when the weather gets hot. This crumbling masonry then gets in the way and pushes the crack open even further. It is therefore best that you have such a crack neatly finished by making it a neat, clean expansion joint or, after having cleared it of crumbling masonry, by placing a so-called ‘back filling’ in it.
Diagonal cracks above the windows from narrow to wide (^)
Do you see these kinds of cracks? Sorry, but this is also bad news. Above your windows is a lintel. This is a wooden, concrete or steel beam that catches all the masonry above your window. These kinds of cracks indicate that your lintel can no longer handle the ballast it has to absorb. There is a chance that your lintel needs to be replaced. They often replace a lintel that is stronger. In this case, get a construction specialist involved.
Diagonal cracks above the windows from wide to narrow (V)
Do you see cracks above your windows that run like a ‘V’? Then this is less drastic to solve. This crack also has to do with your lintel (i.e. the beam above your window that absorbs all the masonry above). Such a lintel is therefore a wooden, steel or concrete ‘beam’. This expands with heat. So he gets longer. But if he gets taller, he should be able to. That is why there should be some space at the ends of the lintel. We call this a butt joint. If it isn’t there or if it’s jammed with something, the lintel won’t widen and it will crush your masonry above your window and cause cracks as shown in the illustration.
The solution is to open the butt joints. Often a so-called ‘lay-up felt’ or ‘sliding oil’ must also be applied so that the lintel can move better. For this, too, the advice, to use a construction specialist.