How to fix a large hump in plaster under window?

[MichaelKuen]

   

I have been going through fixing cracks in the plaster around the house. One of them I noticed extra trouble applying the compound. I checked with a level and it is humped out by a considerable amount. What is the best solution here? How should I go about fixing this myself?

Please ignore the compound in the photo. It is very thin and has nothing to do with the hump. It is located under a window. Cheers!

[EricL]

Hi @MichaelKuen

There are a few possibilities why the hump in your wall has occurred. It could be that the plasterboard has deformed due to long-term moisture damage. Water may have entered the window sill and has damaged the stud framing and window frame causing it to swell and deform under the plaster. Aging has caused the timber frame to shift causing irregularities in the wall.

Repairing it will require you to remove the plaster and examine what has happened to the framing. Once the framing has been repaired and leveled you will have to put new Gyprock CSR 2400 x 1200 x 10mm 2.88sqm Plasterboard RE onto the frame. 

Here is a handy step-by-step guide: How to plasterboard a stud wall

Let me tag our experienced members @tom_builds and @TedBear for their recommendations.

If you need further assistance, please let us know.

Eric

[MichaelKuen]

Thank you again Eric! I will see what I can do.