Putty is the basic material for wall decoration and is mainly used to level the wall surface so that the paint can show its perfect decorative effect. However, the process of puttingty construction can lead to phenomena such as blistering of the putty layer if the details are not handled properly. This causes uneven application of decoration, affects the aesthetics and burst bubbles can spread harmful substances to the body and other hazards.

HPMC for skim coat

Causes of blistering of putty

1. Uneven mixing.
2. Too much water is added to the putty and it is mixed too wet.
3. The water content of the base is too high, while the density is too great or too small. Due to the abundance of voids, the putty has a high water content and is therefore impermeable. It is easy to make the lower part of the putty layer contain air during construction, which is not easily discharged, so it is easy to blister.
4. There are tiny holes in the substrate, and the putty powder squeezes the air inside the holes when scraping, and the squeezed air bounces back into bubbles.
5. The air permeability of a well-sealed substrate is poor.
6. The single layer of scraping is too thick and the air in the putty layer is not completely squeezed out.
7. The substrate is too rough and has small holes. The putty compressed the air in the holes when scraping, after which the air pressure rebounded to form air bubbles.
8. The substrate is too rough and not polished smooth, and the speed of the wall is too fast during putty construction, resulting in uneven putty powder.
9. Impervious to blistering on water resistant paints, high grade concrete and other dense substrates.
10. The putty is prone to bubbling during high temperature construction.
11. The water absorption of the substrate is too low. This causes the putty to remain in a slurry state on the wall for a long time and not dry, making it easy to produce bubbles.
12. The wall is too wet.
13. not easily squeezed out by the mud knife! This is the reason why there are more bubbles on the top of the formwork than on the wall. The wall absorbs a lot of water, while the top of the formwork absorbs very little.
14. Excessive amount of cellulose added.
15. The bursting and blistering that occurs on the surface only after a period of construction. This is mainly caused by uneven mixing, the slurry contains powder particles that do not dissolve in time, after the construction, a large amount of water is absorbed and swollen to form a burst.

The solution to the problem of air bubbles in putty will be explained in the next article. HPMC from Landcel can effectively solve some problems in the use of putty powder. If you need it, please contact us.