Why Gypsum Plaster debonded from concrete wall

[Sumit Civil]

Hello friends we are doing gypsum plaster on concrete wall, at some location gypsum plaster get debonded or slips out from concrete wall.

The structure is made using Mivan formwork where all walls are casted of concrete.

We are using bonding adhesive as suggested by manufacturer before application of gypsum plaster.

We are facing issue of debonding, can anyone help me in solving this problem.







Why gypsum plaster getting debonded?

 

[Mangesh korpe]

As per the observation, gypsum thickness is more. U need back coat(cement mortar /1:4 ratio plaster) require before Gypsum work for ensuring min thick of gypsum plaster.

 

[amd007]

As from the photograph it is seen that bond coat has been applied however if you carefully see the bond coat there are coarse particles added which need to be properly stirred and applied whereby there is both a chemical bond between aluminum finished concrete and bond coat and mechanical bond between the coarse particle and gypsum.

In the bond coat supplied by Saint Gobain, the coarse particles being heavier than the adhesive settle down in the bucket and gypsum workers don't take the pains to stir the mix thoroughly.

As per my experience products from Sunanda, Wallplast are much better considering they have good bond strength as compared to Saint Gobain.

Secondly, it's a good idea to apply grinder before the bond coat application to clear the shuttering oil applied on mivan shuttering which also causes debonding of the bond coat.

Thirdly always get the bond coat checked by supervisor after application of bond coat and make a inspection checklist, only after checking should gypsum plaster be allowed ( most failures occur as there is no check done by building supervisors/engineers)

As regards if after doing gauge patches ( dhadas) if the extra thickness is seen then always go for a dash coat of cement mortar with a prior application of HACKAID from Sunanda Chemicals and rest for one day and then go ahead with gypsum plaster.

If thickness is upto 12mm - only bond coat is sufficient.

If thickness is 15mm to 25mm - apply dash coat of cement mortar with hackaid as bond coat

If thickness is more than 25 mm - Its always better to use gypsum board which can be screwed to substrate and then finished with gypsum punning

Wish you happy Gysuming.....

 

[VIDHYA SAGAR]

Hello friends we are doing gypsum plaster on concrete wall, at some location gypsum plaster get debonded or slips out from concrete wall.

The structure is made using Mivan formwork where all walls are casted of concrete.

We are using bonding adhesive as suggested by manufacturer before application of gypsum plaster.

We are facing issue of debonding, can anyone help me in solving this problem.



View attachment 2978

View attachment 2979

Why gypsum plaster getting debonded?

It is better to apply a 6 mm down aggregate+sand+cement mortar (rough coat) one day prior to apply gypsum plaster.