Cracks occurred after internal wall / re skim over sand and cement

Hi, if you had to apply pva 5 or 6 times your pva was too weak. I use unibond pva, it contains more polymer which is the glue. You should always do a test for suction first, then apply a sealer coat of pva if it needs, followed by a neat coat and apply your skimming when it's tacky for reskim work. Sometimes it pays to put the sealer coat on the day before. When you talk about cracking do you mean crazing? This is the term for drying out too soon. Cracking is normally movement which is solved by expanding metal or scrim depending on the size. This is only a guide as different backgrounds vary.

The original sand cement dried out to quick, in years gone by Central heating was bad for this, sand cement may have a crust on next day, but it needs to dry at a much slower pace to cure itself, once these cracks appear, which I would call crazy paving style, they are due to shrinkage, so just skimming. These is allowing same to happen, solution, pva the wall. Mix up purple bag of bonding coat, while doing so place webbing into whole wall, this will stitch it all. Fibro glass webbing draws in the bonding nice, then apply 2 layers of multi finish, the webbing from webbor, gives a min of five years guarantee external so its great for this, remember phd plasterers, thanks