Make wall opening yourself – preparation and instructions

Make wall opening yourself – preparation and instructions

A wall breakthrough is a measure to make your living space more flexible. There are numerous reasons why a wall breakthrough can be practical or even necessary. However, there are numerous dangers that, in the worst case, can endanger the statics of the house. Read in this text what you have to look out for when breaking through a wall.

Reasons for a wall breakthrough

Walls separate the individual rooms and the interior from the outside world. As planned by the architect, the apartment is basically optimally tailored to the needs of the residents. However, the existing openings in the walls may be no longer sufficient. Reasons can be:

  • Openings for supply lines
  • Widening of doors (e.g. for residents who are dependent on a wheelchair)
  • Window enlargements
  • Installation of hatches and skylights

In these cases, the desired level of comfort in the home can be achieved with a wall opening. Unfortunately, just grabbing the pry hammer does not work. Such a wall breakthrough must be carefully planned.


Three questions must be answered before the wall breakthrough can begin:

1. How big should the breakthrough be?
2. Does the breakthrough pass a load-bearing wall?
3. Has the landlord/homeowner approved the breakthrough?
4. Does the breakthrough violate local building regulations or other laws (e.g. fire protection)?
5. Will electricity, gas, or water pipes be injured if they break through?

Small holes in the wall for power or data cables are usually completely unproblematic. If you want to mount your satellite dish on the outside wall, no static certificate will be required for the conduit cable. In most cases, core drilling is also not a problem. However, you should know exactly where to start the drilling. If you pass a steel beam on the way through the wall, damage to it can very well affect the statics of the house.

However, if windows, doors, or hatches are to be broken into walls, you must clear all other questions in advance:

1. Nothing works without the approval of your landlord. If you simply break through a wall in a rented apartment, your landlord has the right to both immediate termination and full repair of the damage – and all subsequent damage. This damage can range from a damaged parquet floor to the collapse of the entire house. It is also better to discuss all drillings with the landlord in advance. As a rule, they are cooperative and at least very grateful that you asked beforehand.

2. You should refrain from opening in load-bearing walls. Load-bearing walls are all walls over 12 cm wide. If you want a breakthrough in a load-bearing wall, commission a construction company with a structural engineer with the project. Otherwise, you will end up in the “devil’s kitchen” very quickly. You have to reckon with costs of up to 1000 euros per square meter of perforated wall.

3. There are local building codes regarding optics, privacy, and fire protection. For example, you must never break through a fire protection wall. Neighbors to the side can also defend themselves against additional windows that point to your property. First, clarify all legal questions before you carry out a wall breakthrough on a larger scale.

Everything approved and clarified – now you can start

When you have clarified all questions about the wall breakthrough, you can get down to work. In the case of load-bearing walls, you have at least the report of a structural engineer, which shows how you can safely create a wall breakthrough.

To do this, you should first know how to properly build doors and windows:

When building a building, the sides of the doors and windows – the so-called “reveals” are bricked up straight. A so-called “lintel” is inserted over the door and window opening. Lintels are long concrete beams. They have an integrated reinforcement and can therefore easily absorb pressure forces from above. For this, the lintels must rest well on the sides of the reveal walls. The minimum dimension for the lintel from a normal door or window is 25 cm. So if you want to enlarge an existing door or window, you also expose the lintel. The support becomes too narrow or falls away completely. Therefore, in addition to the wall breakthrough for the window or door, you also have to lift new support for a larger lintel.

Since the lintel is a statically load-bearing element, you have to support the wall for the duration of the opening and installation of the new lintel. Two props and a straight, stable wooden beam are sufficient for this.

Preparation and material

To save costs, you can make the wall opening yourself. Follow these instructions. In terms of craftsmanship, it is not particularly difficult. However, it is very noisy and very dirty. That must be clear to you beforehand.

For a successful wall breakthrough you need:

  • Folding rule
  • Spirit level
  • Construction pencil
  • Large angle grinder with a stone saw blade
  • Mortise hammer with a flat chisel
  • Personal protective equipment: safety shoes, work gloves, protective goggles, and a hard hat
  • Foil for covering
  • Wheelbarrow to pull out the rubble
  • If necessary, props and long squared timber
  • Concrete fall
  • mortar
  • Joint iron
  • bucket
  • Trowel

Due to the sensitive statics of a house, the mortising hammer is not the first, but the last tool that you use when breaking through a wall. Prepare the construction site well beforehand, otherwise, the whole project can end in complete chaos.

Instructions for your wall breakthrough

Wall openings generate enormous amounts of dirt and dust. You should therefore empty the room completely. Also, cover everything in the next room with foil. Cover the floor with old carpeting and also with foil. Ideally, cover the area around the floor with thick styrofoam sheets. In this way, falling fragments cannot damage the floor covering.

Now use a folding rule, pencil, and spirit level to draw the exact dimensions of the opening you want. Now at the latest, you have to set the emergency supports so that the ceiling is supported during the construction work.

Switch off all fuses for the room and turn off the water and gas supplies to be on the safe side.

Cut into the wall along the drawn line with the angle grinder. If available, first pre-cut with a small grinder and then retighten with a large angle grinder. Every inch that you now penetrate deeper into the masonry saves you tedious chiseling work. If the breakthrough is to be made inside the apartment, you can now use a trick: drill the wall completely through the corner points with a long stone drill and a hammer drill. You can now see the dimensions of the opening on the other side. Mark the desired opening there and repeat the cutting work. Place safety supports on this side as well.

Now the wall is cut according to the instructions. Now use the caulking hammer and an attached flat chisel to remove the masonry from the INSIDE OUT. The less you injure the outer area, the less work you will have to clad the newly created reveal. It is best to first chisel a hole in the middle and enlarge it steadily. That makes the job a lot easier.


When the wall breakthrough is so far finished, the fine work follows. First chisel out the support for the new lintel. Then chisel away as much material along with the reveal that the previously cut edges protrude or are level with the inner surface.

Now put the new lintel in a bed of mortar. Make sure that the lintel sits straight and has sufficiently large support. Press in as much mortar as possible with the joint iron above the lintel. Let the emergency supports stand until the mortar has completely set. This can take 48 hours. Use the time to clear away the rubble and dust the house again.

If you want, you can now plaster the inner surfaces of the reveals. In the case of a door breakthrough, this is usually not necessary, as you will put a new frame there.

You can check more content in our category ” indoor “

Structural engineer

If you want to make the wall breakthrough yourself in order to save costs, consult the structural engineer again after finishing the work. He will take a close look at your building and tell you whether the work is OK. So you are on the safe side.

Despite instructions: liability committee for our safety

These instructions were made available to you by a trained construction worker. However, we would like to point out that we reject any liability that may arise from following these instructions. Breaking through a wall is an intervention in the statics of a house, which should only be carried out by trained construction workers. The costs for such a project are kept within reasonable limits and are disproportionate to the damage that can result from an unprofessional breakthrough in the wall.