Cut it out then put a skim coat of mud over it.
The ames taping system in used in conjunction with new plasterboard walls to fill the joints between each individual board, and also to FILL the gap at the top and edges. A full plaster skim in not nessessary for this system. Full skim coat only needs to be used if the surFace is badly damaged or uneven.
Could be a Cap coat or a thin coat is sometimes called a skim coat or feather coat
I use basic drywall primer over all of those.
They are the same thing. A skim means just a thin finishing coat of plaster about 3mm or so thick, just enough to cover any minor imperferctions on the wall.
Not recommended.A certain amount of skill is needed as a good finish is required.Not to mention the mess an amatuer would create.However,there are people about with skills that would cost less than a "professional"
The best base coat for painting walls is a simple primer, usually white that will cover the wall in a simple finish. A further coat may be needed afterwards.
Coat the walls with eyeliner.
Lime Based Skim coat (LSC) is made with lime in various formulation and there is no standard formulation. The same consists of mainly lime, oil and several other igredients which changes from place to place. Cement based Skim coat on the other hand is factory made and contains Cement as Binder along with Filler and Additive to support various properties. The basic difference between Lime Based Skim Coat and Cement Based are that the Lime Based Skim Coat are not water resistant and cannot be applied externally, whereas cement based Skim Coat(CSC) can be applied interiors as well as exteriors. They are water resistant. The adhesion strength of the CSC is much higher than LSC. CSC being cement based becomes an integral part of the base plaster hence the durability is very high. LSC on the other hand cannot tolerate any moisture and gets peeled off in contact with the moisture. The Skim Coats are generally done as a base coat for paints and the CSC provide a firm base for the paints. The CSC can be made water resistant which results in lower consumption of Paint by around 20%. The initial cost of application of CSC is slightly higher than the LSC which is compensated by the lesser paint consumption and becomes lower as no primer is required after application of the CSC. For any further information on the properties of the CSC if required I can be contacted in the following email ID: sumonc@adityabirla.com
If you can't solve the seepage problem, the next besrt thing is a water proofing product. Until you are sure you have a tight barrier against moisture, skim coating will be an exercise in futility because it will just bubble up.
I took my left over drywall and cut it into 12-15.5 inch sheets and glued it inside the wall (interior walls) between the studs I wanted to be more sound proof. I did it in the bathroom and my bedroom. Obviously you have to do it after one side is done and before you put the final sheets on the other side. You can do it to outside walls but you will limit insulation space and would have to glue it to the plywood or particle board.
Skim the gorund