Wallpapering can take time, and while it’s tempting to cut corners wherever possible, it’s worth taking the time to prepare properly. Remove the old paper, make sure the wall is dry, and where possible, make sure the wall is flat.
The right kind of wallpaper can cover some imperfections, this is where embossed vinyl wallpapers come in to their own, but you may find that all you need is a base of lining paper. However, if the wall is particularly uneven then you may need to re-plaster
Removing Old Wallpaper
Removing old wallpaper can be surprisingly easy, and maybe even a little bit fun! Modern wallpapers tend to be easier to remove than in the past, with some being peelable straight off the wall.
If your wallpaper is tougher to remove then simply apply water (it doesn’t have to be warm but it can help) and wallpaper stripper, allow them to soak in, and things should go much smoother. Using a steamer will make things even easier, and depending on how much wallpaper you have to remove, it may be worth renting one. If there are any last stubborn spots, soak them and scrape them, ensuring that the scraper is pushed forward up the wall, rather than pressed ‘in to’ the wall.
As tempting as it may be you shouldn’t use washing up liquid. While it will work, the fat-dissolving ingredients can float to the surface of your freshly applied water-based paste, weakening the paste, and potentially dying the wallpaper.
Wallpapering Over Paint
If walls are coated with a chalky covering then this must first be removed. Simply soak with water and wallpaper remover, then wash them down. Once the wall is dry, use a deep primer or lining paper to prepare a smooth, absorbent surface.
If emulsion, oil, or gloss paints have been used to cover the wall then things should be easier, but check if the paint is firmly bonded by using some stick tape, attaching it to the wall, then peeling it off. If there’s paint on the tape then the wall will need to be cleared. If you find the paint is stopping the wallpaper paste from being absorbed it will also need to be removed or painted over with pigmented wallpaper primer
Wallpapering On Plaster
If you need to plaster the wall to get an even finish, then before applying the wallpaper make sure the surface is dry, this can take 6-9 weeks. Keeping the room heated and well ventilated will go a long way to speeding up the drying process. Once the wall is dry it’s worth coating the wall with a wallpaper primer, this will ensure you don’t damage the wall when removing the wallpaper later.
Wallpapering over Filler
In extreme circumstances you may have to use filler. Once the filler is set it should be sanded down to smooth the surface. Before you hand the wallpaper the filled section should be pre-pasted, this will help achieve uniform absorbency.