How to repair cracks in gypsum board

At present, the ceiling decoration in family decoration mostly adopts light steel keel gypsum board ceiling. When the ceiling is covered with gypsum board with high-grade latex paint, after a period of time, cracks may appear, big or small. So why are there such cracks? How can we repair these cracks? This paper introduces the causes of cracks in gypsum board ceiling and how to repair them. Causes of cracks in gypsum board ceiling How to repair cracks in gypsum board

At present, most of the decoration projects use light steel keel gypsum board ceiling, which is widely used in various decoration projects because of its advantages of low cost, easy modeling, good fire resistance and easy construction. Gypsum board coated with high-grade latex paint will have large or small cracks, especially on a large area of gypsum board ceiling. Although this crack does not affect the functional use, it does affect the appearance. It was also listed as a rectification project in the project acceptance. How to prevent this kind of crack, this paper discusses several problems that should be paid attention to and takes corresponding technical measures from the perspective of construction:

First, the position of the expansion bolt fixing the steel hanger is wrong.

This situation mainly occurs in perforated plates. When determining the distance between suspenders, according to the size of the floor module, part of the fixing points of expansion screws fall into the floor holes. At this time, the expansion heads of expansion bolts are in the holes and cannot be fixed, resulting in movable gaps in the ceiling fixing points. This hanging point looks like a stress point, but in fact it will deform when it is stressed. How to avoid this problem:

Causes of cracks in gypsum board ceiling How to repair cracks in gypsum board

1, when the Modou line is fixed on the roof, look for the joint of the floor first. In civil construction, joints are usually filled with concrete, so this joint is chosen as the first line.

2. The construction specification requires the spacing of lifting points to be 900- 1200mm. In concrete construction, the spacing of lifting points can be determined according to the width modulus of the floor within this range, so that the movement of lifting points can be avoided, and the prestressed reinforcement of the floor will be interrupted when the electric hammer is punched, which will affect the stress of the floor.

In case a fixed point falls on the floor hole, there are two ways to deal with it: 1, and re-punch holes in the surrounding space. 2, with 50 x 50 thick 3-4 mm iron plate nut spot welding fastening.

Second, the lifting point and the lifting point appear false stress.

This situation is mainly due to the quality and technical reasons of construction personnel. This kind of problem in the construction of light steel keel ceiling has the following situations:

1. When the bolts and nuts on the hanger are connected with the screws and nuts for fixing the crane, the bolts and nuts are not paid attention to, resulting in kinking and thread damage.

2. The lower part of the expansion screw is hung with hanging steel bars, and the upper opening is not fixed with fixing nuts.

3. Hangers of 6 and 8 have many projects, especially at the end of the project, buy some round steel bars for workers to straighten on site and use as suspenders.

4. The crane is connected with the main keel. Due to the deformation or mismatch of the crane, the main keel is clamped in the middle of the crane and is not stressed at the bottom of the crane.

5. The middle part is connected with the main keel, and the lower part is connected with the main keel, resulting in a movable gap between the main keel and the auxiliary keel.

Under the above circumstances, the leveled keel gypsum board ceiling will become uneven under the action of external force, resulting in tension, deformation and cracking of the facing gypsum board. The solution to this problem is to attach importance to structural construction and take some necessary measures. This situation is more harmful and difficult to repair, so we must pay more attention to it in construction. Measures to solve these problems are:

1. Tighten the bolts and nuts along the thread, and don't damage the thread with excessive force.

2. Before the disc steel bar is used as a suspender, it must be qualified new steel bar, which can only be used after cold drawing or straightening with a straightening machine.

3. The deformed parts of the main and auxiliary keel pendants and large cranes must be processed with wire cutters during construction to meet the applicable requirements of construction, and unsuitable or uncoordinated accessories must be discarded.

4. When hanging the auxiliary keel, make sure that the main keel and the auxiliary keel are close together. When the pendant is connected with the main keel, clamp it with wire cutters so that there is no gap between them.

Three, fixed gypsum board self-tapping nail spacing is too large or part of the self-tapping nail false stress.

When installing gypsum board ceiling, self-tapping nails must be fixed on the keel. During the construction, the workers did not spring the thread on the gypsum board according to the keel spacing size, which led to some screws not being fixed on the facing keel. When fixing the self-tapping nail, the electric screwdriver is not used, but the hand electric drill without speed regulation function is used, which leads to the self-tapping nail penetrating the paper surface of the external gypsum board because of the too fast construction speed; At the joint of two gypsum boards, especially when cutting burrs, because the width of the keel is 5cm, a single gypsum board is placed on the keel, and only 5cm is deducted for the joint, and the tapping nail does not pay attention to or bias the burr of the gypsum board, resulting in the gypsum in the gypsum board bursting; Self-tapping nails are not in accordance with the specified size. , only in the process of operation is easy to find. If the operator's consciousness is low and he doesn't rectify it in time, it is often not easy to be found in the subsequent mutual inspection and hidden inspection. Once the gypsum board is damp, it will be deformed by external force, resulting in cracks at the joints of gypsum board. Solutions to such problems:

Causes of cracks in gypsum board ceiling How to repair cracks in gypsum board

1. Strengthen on-the-job training of operators.

2. If the self-tapping nails are not driven into the keel, they should be returned in time and repaired and reinforced at intervals of about 2-3 cm.

3, gypsum board fixed self-tapping nails, edge spacing size is less than 180mm, middle spacing size is not more than 250 mm ..

4, gypsum board tapping self-tapping nail burr, as far as possible to the board, from the edge seam is greater than 15mm, so as to ensure the nail on the keel, and can reduce the gypsum burst inside the gypsum board.

Four, large area gypsum board flat roof construction

Due to physical reasons, such as thermal expansion and cold contraction, dry contraction and wet expansion. Especially in the rainy season, when the air humidity is high, the gypsum board ceiling will fall off, wrinkles will appear at the joints, and the top will gradually level off after the weather is fine. After several iterations, cracks will appear at the joints. How to avoid this phenomenon:

1. Like a construction project, according to the plane size of the ceiling, natural contraction joints are left, and two opposite keels are set at the expansion and contraction joints. Gypsum board joints are fixed on two facing keels respectively, and the joints naturally leave a seam of 8- 10 cm. This joint is repaired with elastic caulking putty of the same color as latex paint.

2. For the main keel of a large-area suspended ceiling, the spacing is about 10m, and the lateral uneven stress of the main keel is adjusted with two diagonal tie rods in different directions of about 10.

Five, caulking putty and tape construction technical problems

Gypsum board ceiling is affected by temperature expansion and air contraction when it is wet. When plasterboard is patched, a seam of about 5mm is usually left to fill the seam of plasterboard. It has been repaired successively with oily gypsum plaster, water-based gypsum plaster, putty putty for elastic joint filling, all kinds of adhesive gypsum for gypsum board factory, and sewing tape, including medical cloth rolls, polyester cloth strips, paper tape with fibers, glass fiber mesh belt and perforation in earlier years.

At present, there is no unified approach to the treatment technology of gypsum board joints. The effect of mending the joint with elastic putty is good, but the cost of large-scale construction is high, so it is only suitable for small-scale use. In engineering, it is suggested to repair the joints with adhesive gypsum provided by gypsum board factory, and then stick perforated kraft paper tape with adhesive gypsum, which is relatively less cracked. In this construction process, we must pay attention to two problems:

1, joint filling putty to repair the joint, let it dry thoroughly as far as possible, and then stick joint tape.

2. During the drying process, a small amount of caulking putty may dry and crack. It is suggested that putty should be mended before caulking, and polished with fine sandpaper after drying.