What is the reason for the ceiling cracking? How to prevent the ceiling from cracking

We all know that ceiling is a common decoration step. Many people have ceiling in their homes, especially in the living room. The style and specifications of the ceiling are different, and the decorative effect will be different. Some people will find cracks after the ceiling is installed. So why are there cracks in the ceiling? Let's take a closer look!

Why is the ceiling cracked?

In fact, this problem is relatively complicated. The following are some common reasons for ceiling cracks.

①Caused by keel deformation: Most of the deformation is caused by wooden keels, or the wooden keels in the light steel keel part will cause the wooden board to deform. It is recommended that you use light steel keels as much as possible, and then evenly place anchor points every 30 cm.

② The gypsum board is not cut correctly, the paper surface should be scratched at the joints, and L-shaped gypsum board should be used at the corners to prevent cracking.

③There is no bandage or expansion joint between the ceiling and the wall.

What to do if the ceiling is cracked

Ceiling cracks caused by material reasons

Conventional indoor ceilings include light steel keel ceilings, wooden keel ceilings, aluminum gusset plate ceilings, etc. If it is for home decoration, due to the relatively small quantity, whether from the perspective of strength or moisture-proof, anti-corrosion, durability and aesthetics, except for the kitchen and bathroom area, it is recommended to install light steel keel gypsum board (or Et board) ceilings for home decoration, so the main discussion here is light steel keel gypsum board ceilings. There are two types of materials for ceilings due to material reasons, namely base material reasons and surface material reasons. The base materials include light steel keel base (hanging rods, keels, pendants), base plywood, gypsum board, anti-cracking treatment materials, and the surface materials include putty and latex paint.

① The cracking of the ceiling is caused by the base material of the light steel keel. This problem rarely occurs in home decoration ceilings, unless the quality of the purchased hanging rods or keels is extremely poor (the extreme here means no strength at all). Why do I say this? Because unless it is a large villa, the ceilings are often not for people to live in. The selected hanging rods are φ6mm~φ8mm and the keel thickness is not less than 0.8mm to meet the strength requirements of the base;

② The ceiling cracks are caused by the base plywood and gypsum board materials. This problem is relatively rare in home decoration ceiling cracks. The amount of suspended ceilings in home decoration is generally small. In order to better prevent cracking caused by long-term slight settlement or vibration in the future, I personally recommend making a double-layer gypsum board ceiling or a flame retardant board + gypsum board ceiling, especially in larger corridors or shaped ceiling areas, it won’t cost much more.

③ The cracking of the ceiling is caused by the anti-cracking treatment materials. The fiber mesh strips or kraft paper used are not strong enough, and the anti-cracking sealant has insufficient bonding strength, which can easily cause the ceiling to crack during the daily construction process. It is recommended to choose qualified products;

④ Ceiling cracks are caused by surface materials such as putty and latex paint. We know that the main functions of putty are beautification, leveling, and overcoming cracks. If there is a problem with the ratio of putty powder or the quality of cementitious materials is unqualified, it is easy to cause the putty layer to peel and crack. Don't buy putty that needs to be added with glue. Not only is the quality poor, but the formaldehyde content is excessive and it is not environmentally friendly. The same is true for the latex paint of the finishing layer. I personally recommend choosing latex paint with a certain elasticity and toughness of the paint film, which will better overcome the effect of fine cracks.

In view of the ceiling cracks caused by the above material reasons, we should keep our eyes open when purchasing materials and not be lucky enough to save a few money, otherwise the gain will outweigh the loss, because if the ceiling cracks due to material problems later and needs to be repaired again, apart from the repair materials, the labor cost may be more expensive.

Construction process problems cause ceiling cracks

According to experience, construction process problems are often the most common cause of ceiling cracks.

If your home ceiling is cracked, don't rush to repair it, because the gypsum board ceiling has to go through a cycle. After the decoration is completed, it will go through a winter and a summer, which is a cold and hot cycle. If cracks appear in the middle of this cycle, don't deal with it yet. After a cold and hot cycle, repair it. At least it will take a long time. If it is done well, it will not crack for many years.

How to prevent ceiling cracking

Solid construction

First of all, the construction must be done in a solid manner. The skeleton must be ensured to be horizontally and vertically pulled firmly without looseness. Before installing the gypsum board, you must first brush glue on the contact surface of the keel frame and the gypsum board as a bonding and fixing treatment. The screws for installing the gypsum board must be accurately in place and evenly distributed. They cannot be too far apart or too dense. The screws must be accurately placed on the skeleton, must be firm without looseness, and the screw cap head must not be higher than the gypsum board surface. There must also be a drop of about 2 centimeters to facilitate scraping and filling the nail head. The overhead joints must be connected with screws on wooden squares or wrenches to connect the overhead gypsum board joints.

Gypsum powder for ceiling joint filling

Fill the joints of the suspended ceiling with plaster. Gypsum powder must be used as the filling material for the joints. Gypsum powder shrinks little, hardens quickly and has a high hardness. If it hardens too quickly and is difficult to construct, you can add some putty powder to mix and use it. The plaster powder for filling joints must be dry before you can brush it with white latex and stick it on mesh tape or kraft paper for anti-cracking treatment. The nail holes in the gypsum board ceiling must be filled and dried before the first coat of putty powder can be applied. If the nail holes are not filled first and the first coat of putty powder is applied, there will definitely be potholes at the nail holes due to drying and shrinkage. The first coat of putty powder is a covering treatment, and the second coat of putty powder is a very good leveling treatment. Generally, a skilled master only needs to scrape the ceiling twice. Do not rush when scraping the ceiling. The second coat must be done after the first coat is dry.

Sand the ceiling after it is fully dry

After the ceiling putty powder is scraped, it must be fully dried before it can be sanded. After sanding, roll it with clean water to collect the dust. This will also reveal some small potholes for appropriate repairs. Then simply sand it and you can apply the first coat of latex paint. After the first coat of latex paint is dry, simply sand it with fine sandpaper to remove some fine particles attached to the surface. Then you can apply the second coat of latex paint. Two coats of latex paint can generally achieve the paint thickness and paint effect. Too much is not good.

Finally, the indoor ceiling must be constructed according to the above requirements and cracks must not appear. The construction of ceiling filling, putty powder and latex paint must not be rushed. They must be fully dried over and over again before the next construction can be carried out. If you do not follow such strict requirements, problems are bound to occur sooner or later.