Problems&Solutions

Common problems in construction of wall putty and solutions

Blistering

▲Phenomena

Bubbles are generated during the construction process and after a period of time, the surface of the putty foams.

▲Cause

① The base is too rough and the speed of scraping is too fast;

② The putty layer is too thick for first construction, over 2.0mm;

③The water content of the base layer is too high, and the density is too large or too small. Because it contains abundant voids and the putty has a high moisture content, it is not breathable, and the air is enclosed in the void cavity, which is not easy to eliminate;

④After a period of construction, bursts and blisters appear on the surface, mainly caused by uneven mixing. The slurry contains powdery particles that are too late to dissolve. After construction, a large amount of water is absorbed and swells to form bursts.

1

▲Solution

① When appear a lot of bubbling putty surface, use a spatula to directly crush the small blisters, and use a suitable putty to scrape the foamed surface layer;

② Putty is generally mixed evenly, then let it stand for about 10 minutes, then use an electric mixer to mix it again and put it on the wall;

③If there is blistering on the second or last surface of the construction, a spatula should be used to remove foam before the watermark is removed to ensure that no blistering occurs on the putty surface;

④For particularly rough walls, generally choose thick putty as the base material;

⑤In the environment where the wall is too dry or the wind is strong and the light is strong, first wetting the wall with clean water as much as possible, and after the wall is without water, scrape the putty layer.

Drop powder

▲Phenomena

After the construction is completed and dry, the powder will fall off when touched by hand.

▲Reason

①The polishing time for internal wall putty powder is not well controlled, and the surface has been dried and then polished will be powdered;

②External wall putty powder, the coating is relatively thin, in the high temperature in summer, the water evaporates quickly, and the surface layer does not have enough water to cure, so it is easy to take off the powder;

③The product exceeds the shelf life, and the bonding strength is decreasing;

④The product is stored improperly, and the adhesive force drops significantly after absorbing moisture;

⑤The high water absorption rate of the base layer causes the putty to dry quickly, and there is not enough moisture for curing.

2

▲Solution

① When appear a lot of bubbling putty surface, use a spatula to directly crush the small blisters, and use a suitable putty to scrape the foamed surface layer;

② Putty is generally mixed evenly, then let it stand for about 10 minutes, then use an electric mixer to mix it again and put it on the wall;

③If there is blistering on the second or last surface of the construction, a spatula should be used to remove foam before the watermark is removed to ensure that no blistering occurs on the putty surface;

④For particularly rough walls, generally choose thick putty as the base material;

⑤In the environment where the wall is too dry or the wind is strong and the light is strong, first wetting the wall with clean water as much as possible, and after the wall is without water, scrape the putty layer.

Fall off

▲Phenomena

The bond strength between putty and base layer is poor, and it falls off directly from the base layer.

▲Reason

① The old wall is very smooth (such as tempered putty, polyurethane and other oil-base paint), and the putty powder has poor adhesion to the surface;

② The new wall is cast with a template, the surface is smooth and contains a large amount of release agent (waste engine oil or silicone);

③ For wooden substrates, metal substrates and other non-mortar substrates (such as plywood, five-plywood, particle board, solid wood, etc.), putty is directly scraped, due to the different surface expansion and contraction ratios, and such products have strong water absorption and rigidity inner wall putty can't be deformed along with it, generally it will fall off after 3 months;

④ The putty exceeds the shelf life and the bonding strength decreases.

3

▲Solution

① Remove the peeling layer and deal with it according to the following conditions;

② Polish the old wall to increase the surface roughness, and then use the interface agent (10% environmental protection glue or special interface agent);

③ Use a degreasing cleaning agent to remove the release agent or other grease components on the surface, and then apply the putty;

④ Use two-component or special plywood putty for construction;

⑤ Please use special new putty for exterior wall surface of marble, mosaic, ceramic tile and other exterior walls. Use within the putty shelf life.

Peel off

▲Phenomena

Between the two layers of putty or between the putty and the substrate peel off each other.

▲Reason

① The old wall is very smooth (such as tempered putty, polyurethane and other oil-base paint), and the putty powder has poor adhesion to the surface;

② The new wall is cast with a template, the surface is smooth and contains a large amount of release agent (waste engine oil or silicone);

③ For wooden substrates, metal substrates and other non-mortar substrates (such as plywood, five-plywood, particle board, solid wood, etc.), putty is directly scraped, due to the different surface expansion and contraction ratios, and such products have strong water absorption and rigidity inner wall putty can't be deformed along with it, generally it will fall off after 3 months;

④ The putty exceeds the shelf life and the bonding strength decreases.

4

▲Solution

① Remove the peeling layer and re-select the special putty to scrape;

② For severely chalked construction surfaces, it is best to use 10% sealing primer diluent for sealing, and after drying, perform corresponding putty layer or other construction;

③ Putty, especially internal wall putty, shorten the interval between two putty constructions as much as possible;

④ Pay attention to the protection during the construction process. During the construction of the putty or within 8 hours after the construction, the putty should not be infiltrated by water.

Crack

▲Phenomena

 After putting the putty on for a period of time, the surface cracked. 

▲Solution

① The putty that has been cracked needs to be removed. If the crack is not too big, flexible putty can also be used for the first construction, and then the construction shall be carried out according to the standard construction method;

② Each construction should not be too thick. The time interval between the two constructions must be more than 4 hours. After the front putty is completely dried, the back scraping is performed.

▲Reason

① Construct before the base is completely dry, and the construction requires that the moisture content of the base is less than 10%;

② The bottom putty is not completely dried, just pass the surface, the surface layer is dried first, and the inner layer is still in the drying process, resulting in different degrees of shrinkage between the layers and easy to crack;

③ When the base layer is processed, if the mending and flattening materials are not completely dry, the internal wall putty with strong hardness is applied on it, which is easy to cause cracking;

④ The construction is too thick, the internal drying is slow, the surface drying speed is faster, and it is easy to cause cracking.

5

Turn yellow

▲Phenomena

After the putty construction is completed, part or all of it will appear yellow soon.

▲Reason

It mainly occurs on the old indoor walls. The old wall putty uses a lot of PVA glue. The glue is aged and decomposed to produce unsaturated acid. The unsaturated acid reacts with the calcium ions in the putty to generate corresponding yellow calcium salt.

▲Solution

①Roll coating twice with environmentally friendly glue, and then apply environmentally friendly water-based interior wall putty after it is completely dry;

②Roll on two coats of white seal primer, and then scrape the putty after it is completely dry;

③Use paste putty for construction, or use board putty for construction.

6

Technical measures to overcome cracks in wall thermal insulation project

7

①The crack resistance of the anti crack protection layer is the main contradiction, and the special anti cracking mortar must be used and the reasonable reinforcement net must be adopted,
Adding proper amount of polymer and fiber to mortar is effective for controlling cracks.

②By the plastering mortar and enhance the anti crack protective layer net composed of the whole system plays a more critical crack resistance effect. The deformation should be greater than the worst-case limit, the deformation of the flexible tensile mortar (dry shrinkage deformation, deformation, deformation temperature, humidity and chemical deformation) and primary deformation and the protective layer, so as to ensure the requirement of crack resistance crack resistance. Compound in the mortarreinforced network (such as the use of fiberglass mesh cloth), on the one hand can effectively increase the tensile strength of the anti crack protective layer, on the other hand, can effectively disperse stress, can be originally may have wider cracks (crack) dispersed into many smaller cracks (cracks) to form the anti cracking effect. It is important for early alkali resistance coating material and surface coated on glass fiber cloth, glass fiber varieties and has the decisive significance to the long-term alkali resistance.

③Decoration layer of materials not only to crack, but also breathable (moisture) and with the insulation layer coordination, it is best to choose elastic exterior wall coating.
Other Interface layer, insulation layer, bonding and reinforcement materials should also be supplied by professional manufacturers to improve the traceability of quality problems.

Why does the paved tiles crack?

Generally, there are three reasons for tiles cracking: one is quality of tiles itself; the other is the problem of tile paving construction, and the third is the base layer and external forces. Below we will introduce the specific reasons in detail:

8

Tiles problem

Some tiles have high water absorption rate and insufficient compression resistance, which causes the tiles to crack; The tiles are not burnt through during the firing process, and they crack during transportation, storage, and use. The quality of the tile itself is problematic, and the cracking texture is generally mesh-like, such as the size of fine hair, the proportion of cracks is relatively high, and there may be multiple cracks in a tile. This situation generally occurs in relatively low-end products.

Paving problem

①High-grade cement is used: Ordinary No. 425 ordinary Portland cement is generally used for tile paving. The mixing ratio of cement sand is 1:3. If the cement grade is too high, the cement will absorb a lot of water when the cement mortar is solidified. At this time, the tile moisture is excessively absorbed, it is easy to be cracked. Generally, it is manifested as multiple tiles cracking, and the direction of the cracking texture is irregular.

②Ceramic tiles are laid on hollow drums causing tiles to crack: hollow drums and non-hollow drums, cement mortar and ceramic tiles have different expansion coefficients, which cause the tiles to deform and crack. Generally, the distribution of cracked tiles is irregular, and the cracks are also irregular. The cracks are linear and have different lengths. The percussion is low, muffled and muddy.

③No seams are left in the paving, the expansion and contraction of the ceramic tiles and the base layer are inconsistent, and thermal expansion and contraction cause the ceramic tiles to crack. Generally, there are cracks in the corners of the tiles, small cracks on the surface, and relatively short textures.

④ The ceramic tiles are cracked after cutting : dark cracks are formed during the cutting process. After a period of time, the ceramic tiles are affected by shrinkage of cement and external forces.

Base layer and external forces

①Wall deformation and cracking Due to its own geological problems, a certain degree of subsidence will occur, which will cause the wall to deform and crack and also cause tile cracking. Generally manifested as continuous and regular cracks.

②Cracking the tiles caused by the wall vibration caused by smashing the wall

③It is too close to some heat sources, and the temperature changes due to over cooling and overheating, and thermal expansion and contraction cause the tiles to crack. This phenomenon generally occurs in kitchens, boiler rooms, etc.