Specialist in Modern and Traditional Techniques
Plasterer Covering Surrey and London
Professional Plasterer at Affordable Costs

How long do I have to wait before I can paint my new plaster? 

In general you should wait at least seven days or when the plaster has changed colour from a dark brown to a light pink.

Do I have to remove the wallpaper before the walls are plastered?

Yes all paper should be removed to ensure a proper adhesion. 

After removing the wallpaper I noticed the walls are all cracked and grazed do I need to get them replastered? 

Depending on the level of damage. In some cases they can be filled with a smooth filler, but to achieve a uniform smooth finish the walls should be replastered.