Expansion of an aperture in a bearing wall: maximum dimensions, GOST requirements and work technique

01.09.2019 House, Repair
Expansion of an aperture in a bearing wall: maximum dimensions, GOST requirements and work technique

If you want to install a door in the load-bearing wall or make it arched opening, you will certainly need to increase it. In an interior wall made of lightweight material, you can cut an opening of any shape, while an opening in a load-bearing wall requires some attention.

What are the risks. Documentation

openings in load-bearing walls

Not all factory doors are suitable for installation in the interior doorway, which is especially true for those apartments that were lined up in Soviet times. Only the expansion of the existing opening will save the situation. The new door blocks have standard sizes, which makes them very different from older products that have stood still for several decades.

Height or width can be excellent parameters. It is possible to solve the problem due to the functional and decorative arrangement of the interior passage. The hole in the wall can be enlarged or reduced. Expanding the opening in the load-bearing wall is not always safe. If you are planning to restore the partition, which is not the functional basis of the building, nothing bad will happen. In this case, we are talking about walls made of aerated concrete, drywall or any other building material. But the work can be troublesome when it comes to the need to transfer the metal profile.

If you want to increase the passage in the load-bearing wall, then such a reconstruction will be a redevelopment. Work in this case should be carried out in accordance with a separate project, which contains an engineering calculation of the redistribution of loads on the floor after the volume of changes. When expanding the opening in the load-bearing wall, it is necessary to collect some documents that are prescribed by regional requirements. This should include:

  • documentation on the property of housing;
  • a certificate from the local BTI;
  • extract from the house book;
  • reconstruction plan from the architectural organization;
  • floor plan for construction;
  • plan for all stages of work.

In the end, the decision to increase the passage can be a real red tape . This list of documents is not necessary for a tick, but for the safety of people who live in and around the apartment. If the supporting partition is unauthorized damaged, this can lead to the collapse of the wall and the collapse of part of the house. It is necessary to avoid irreparable consequences by strengthening the opening.

Calculations of expansion parameters

doorway device in the load-bearing wall

If you have a door structure under which you can fit a hole in the wall, you can calculate the exact parameters. Cut out the opening by eye, it is necessary to carry out accurate marking. You must measure the width and height of the existing door, the width and thickness of the door frame that comes with the kit.

The next step will be to find out what is the width of the platbands that you plan to install. It is important to choose the right sills and measure its height. It may not be. Before you begin to expand the opening in the load-bearing wall, you need to determine the width of the passage, which will be composed of the thickness of the rack, the width of the door leaf and the technological clearances on each side of 2 cm. You can determine the height of the doorway by adding the height of the door to the thickness of the box . The technological gap should be added to the obtained value.

Typically, the wall thickness is 75 mm. If other indicators are available, add extras when the walls are wider. An alternative solution is to purchase a box with a narrow beam. Before proceeding with the expansion of the opening in the bearing wall, measurements and marking should be carried out, conducting work with high accuracy. If the gaps are taken with a margin, they may not overlap the wide platbands for decorative decoration.

Calculation of the arch according to state standards

If you want to remove the arch arch when moving to the next room, you can’t avoid the extension of the transition. Before making an arched opening, it should be calculated. The opening can have any type of configuration. The shape of the arched arch can be any, while the curved curve can be attributed to a creative look.

When arranging the opening in the load-bearing wall, it will be more difficult to make a classical arch with the correct bend of 45 cm, so you need to stock up on certain equipment for calculations on a scale of 1 to 50. Among the tools and materials you should select paper and compasses .

When calculating, you will need to use the Pythagorean theorem from the school curriculum: R² = L² + (R²-H²). The well-known formula of Pythagoras made it possible to deduce, and the masters of the construction field - use the formula for calculating the radius of the circle of the arch in the opening. You will need to use the calculation based on the following formula: R = L² + H² / 2H.

To determine the radius of the arch, you can use simpler, but not entirely accurate calculations. For this, an extended doorway is shown on paper. Previously, a section of wallpaper was used for this. After that, a compass should be installed on the axis of symmetry and, changing the radius, draw several arcs. So you can choose the best option, the remaining radii are then erased.

Where to start

Before installing the opening in the load-bearing wall, dismantle the old door structure and strengthen the opening. If the work is carried out in an old prefabricated house, then reinforcement can be done after concrete cutting is completed. As for the brick openings, they require special attention. When manipulating a brick wall, certain tools and materials should be prepared, such as:

  • coupling bolts;
  • coupling channel;
  • studs;
  • metal corners;
  • steel plates;
  • cement mortar;
  • gas cutter;
  • electric drill;
  • grinder.

The coupling bolts must have a diameter of 20 mm. The diameter of the studs is 16 mm. Steel plates should be made of sheet steel. Instead of a grinder, an electric cutter or a gas cutter can be used. Diamond wheels should be prepared for the angle grinder. You can cut concrete using a variety of tools, but diamond cutting is the most suitable option.

You will need jacks or supports for the duration of the work. When you need to cut a brick wall, you should also prepare a punch. The class of material used for reinforcing and the cross-section of the beam should be determined during preliminary calculations of the load.

The figures obtained should be entered into the design documentation of the redevelopment of the room. The profile of the steel channel should enter the thickness of the brick wall by about 25 cm. With this in mind, its length is selected. To install the coupling bolts in the channel, holes are made, there must be at least 3 pieces. This will be enough for an average length opening. Channel ties are located at a distance of 50 cm.

Dismantling

extension of the doorway in the load-bearing wall

Before starting the doorway in the load-bearing wall, first you need to create a marking on the plane. The process will be slightly easier if you use diamond cutting. Circles that reach cut depths of up to 10 cm will be an excellent option. During operation, the walls are wetted with water, which will reduce dust formation. It is important to keep in mind security features, namely:

  • a protective suit;
  • a respirator;
  • gloves;
  • special glasses.

The device of a doorway in a bearing wall provides two-way operation. It will be necessary to cut from different sides due to the massiveness of the partition. Before dismantling, the opening is reinforced. The best option to increase the reliability of the load-bearing partition is to use welded frames that are pulled together with studs through the walls.

When expanding the doorway in the concrete bearing wall, you should work with small areas in the form of squares or rectangles. In brick partitions, a through cut is usually done, while the blocks themselves must be shot down by a puncher, after which you can use a sledgehammer if necessary. When it comes to concrete, do not use a hammer drill for it. Vibration can be damaging to the panel, resulting in microcracks and weakening the entire structure. Brick walls require a different approach.

Additional doorway requirements and standards

enlarging the doorway in the load-bearing wall

Before you start to enlarge the opening in the load-bearing wall, you need to figure out which building is being carried out. If the building is block or panel, but was not designed by MNIITEP or Mosproektomtul, then the doorway can be completed. But certain requirements will be imposed on it.

For example, the opening should be removed from the outer wall or from the existing opening in the bearing wall by a distance of 1 m. When arranging the opening in the bearing wall, masters quite often ask what the width of the box should be. Usually this value is 900 mm. Rarely, and in some series, the opening width is between 1000 and 1200 mm. However, this value should not be exceeded.

If you started a widening of the doorway in the load-bearing wall, and the building was designed by MNIITEP, then such work may be prohibited if the apartment is located on the first or second floor. This is due to the fact that in these cases, the remaining sections of the wall will not correspond to the calculations for strength under load from higher floors. MNIITEP can authorize and expand the doorway in the load-bearing wall in only one partition. From this it should be concluded that the capabilities of the opening device and its location, as well as the size will be determined by the organization that is the author of the project.

The owner of the property will need to receive a technical opinion on the safety and permissibility of redevelopment. On the basis of the conclusion and design documentation, the relevant coordinating authority will issue a repair permit. When expanding the opening in a brick supporting wall, SNiP 3.03.01-87 should be used, where the requirements for enclosing and supporting structures are specified.

Methods of expansion and features of the work

increase the opening in the load-bearing wall

You can use one of several methods to expand the opening. The method can be crude, in this case the following are used:

  • hammer;
  • punch;
  • jackhammer.

At the first stage, it is necessary to outline the contours on the wall, and then use the tools to bring down the excess material. Such a process is quite laborious, and microcracks formed due to shock loading can cause a decrease in the strength of the wall. An increase in the opening in the bearing wall can be carried out by dry cutting. Here you will need a grinder, with the help of which it is quite simple to increase the opening along the intended contour. The disadvantage of this process is that the wall should be cut on both sides.

Dry cutting entails the formation of a large amount of dust, in addition, you will encounter rapid wear of the diamond blade. Cutting can also be wet. This method is accompanied by the use of a spray gun, with which you can irrigate the surface in the process of working with an angle grinder. More rational is the use of a construction cutter with a diamond blade. It should have a large diameter. You should also use the water tank.

Things to consider before starting work

Before enlarging the doorway in the load-bearing wall, you must make sure that there are no hidden wiring, pipes or fittings inside the partition. Perhaps there is a chimney inside. In order to obtain detailed information, you should use a metal detector. When any obstacles are found, they can be eliminated by moving the wiring to another place or by stepping 300 mm from the chimney. If there are pipes inside, they are dismantled and transferred, but for this you will need the help of a specialist.

The main stages of increasing the opening

Re-planning the opening in the bearing wall in the first stage involves the removal of extensions and platbands using nail clipper. From loops it is necessary to remove a cloth, having lifted it from below with a crowbar. Vertical racks must be cut off with a grinder and torn off with a nail clipper. If there is an increase in the height of the opening in the bearing wall, the upper jumper must be torn off. Otherwise, it remains in place.

The contour of the increase should be marked around the perimeter. Holes are made along the marking line with an impact drill to simplify dismantling. On each side, you need to cut the panel. After cutting the reinforcement with a hammer, it is necessary to eliminate the remains of the wall. The aperture should be reinforced with metal corners, pieces of rod or planks.

In conclusion

Now you know the parameters of the maximum aperture in the bearing wall. But this is not enough for successful work. For example, if you want to work with a brick wall, then you need to exclude its collapse. An overhead beam should be installed above the doorway. As it can be used reinforced concrete beam or metal channel. On top of the opening you need to perform a cut of a niche by going to the walls. A beam is laid there. All voids above and below it are poured with concrete mortar.

As soon as the concrete hardens, you can expand the opening. To do this, use a cutter to cut the brickwork along the contour. The cut-out opening should be less than the beam installed on top. The cutter should be directed perpendicular to the wall. If you want to transfer the opening in the load-bearing wall, you will have to cut on both sides, because the partition has a thickness of more than 10 cm.

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