Decorating 101: Wall Preparation…
Our guide below is a text heavy yet exhaustive guide to preparing your walls prior to decorating, this includes tasks such as stripping wallpaper, sealing contaminated surfaces, covering damp problems and water stains along with an explanation of the types of painted surfaces you may encounter plus a guide to using lining papers effectively to cover poor wall surfaces.
Previously Wallpapered Surfaces.
It really is a must to strip each wall completely before repapering. There is no way to guarantee that any previous wallpaper or lining papers will stay adhered to the wall once the new wallpaper is overhung.
Many factors will put your new wallpaper at risk if you do try to overdecorate existing wallcoverings including:
- Increased wallcovering weight
- Breakdown of the previous adhesive over time
- Moisture from new adhesive releasing the existing hold
- Tension when newly applied wallcoverings are drying
Stripping advice.
Peel away any top layers of wallpaper or vinyl where possible, with this washable layer of pattern removed you will be able to apply moisture into the lining layer which will begin to soften existing adhesives.
- Wet or moisten the lining paper several times with warm soapy water or diluted wallpaper stripper, we do mean generously too!
- Do this with an old brush, a sponge / cloth or even a garden pressure sprayer allow short intervals between applications until the paper becomes soft.
- Scrape the lining paper layer away with a wallpaper scraper or sharper broad stripping knife, be cautious as to not to dig into the wall too much.
Can’t get that top layer off? It’s time to start scoring!
Using a fine bladed knife such as our snap off versions or a specific wall scorer to produce holes or tracks through the surface layer. If using a knife, use a criss-cross method to maximise effectivness.
Scoring is especially good when tackling painted, varnished or cushion vinyl’s (the type that is often used in for kitchen & bathroom wallpapers). Once scored, use the above soaking techniques of applying moisture to the surface, this will slowly penetrate and allow removal of a single section at a time.
This will be more time and labour intensive but persevere with the moisture applications and you will save damaging the wall from a heavy handed scraping approach.
New Plaster.
If you have moved into a new build home, have undecorated or newly plaster walls then check how long you have to wait before you can over decorate from the tradesmen that have completed the job. It is worth noting that some plasters may require up to six months to pass before decorating with vinyl wallpapers.
These porous surfaces will benefit from a coating of wall size prior to wallpaper hanging, this dilute mix will lightly seal the surface resulting in reduced moisture absorption (stealing it from the adhesive) and allowing more slip when positioning the final wallcovering. Use as instructed, allow to dry before hanging.
New Plasterboard.
Firstly, seal with a good wall primer to prevent the moisture from softening the plaster and making it porous.
Hang a good weighted lining paper as a your prepartaion layer for your chosen wallpaper, this will give you the best results and minimise the risk of seeing the individual plasterboard panels which make up your wall.
Use a low-moisture adhesive (ready mixed wallpaper adhesive) and a non-woven (paste the wall) lining paper as an alternative to priming the plasterboard.
Emulsion Painted Surfaces.
If the surface is clean, dry and sound follow these instructions:
- Matt finished walls. Lightly sand the wall surface and apply a coating of wall size.
- Silk or Mid Sheen finished walls. Prep as above and include a small amount of fine plaster to the wall size mix to give a great key.
Flaking emulsion? This must be stripped away, wall scraping and sanding back to a good sound surface.
Dirty or Contaminated emulsion? This will prevent the adhesion of any wallcovering, a coating of oil based plaster primer will seal any contamination behind the primer allowing you to decorate normally.
Water Stained or Damp Walls? Water stains can penetrate wallcoverings via the adhesive or if the original problem returns, a coat of stain block paint on the area will seal this to allow decorating to take place.
Damp areas cannot be wallpapered, ideally fix the source of the damp in the first instance and treat as above. If this is not possible or your damp is a consequence of a third party two options are possible.
A. Wait until a good spell of dry weather has occurred and the damp has dried out (for now), at this time a coat of damp stop paint will seal the wall for decorating.
B. Can’t wait? Use a damp proof foil, this non-porous material will if adhered correctly stop penetration of moisture through to your wallcovering. Follow instructions, use the correct adhesive and adhere to drying times.
Oil Painted Surfaces.
Rub wall down thoroughly with a sanding block and rinse off with clean water, fill any cracks and hang lining paper.
Gloss paint must be stripped back and sanded smooth.
Lining Paper.
To get the best finish we would always recommend the use of a lining paper, this preparation layer can reduce labour by covering fine surface imperfections and smoothing over large areas in a short time.
Produced in various weights per square metre choosing the correct lining paper for your walls is quite simple, the worse your walls appear to be the heavier in weight lining to use.
Available from 1000gsm to 2000gsm (grams per square metre).
To remove the risk of a seam landing on a seam hang lining paper horizontally and butt-join each sheet.
- Cut strips of paper to cover the length of the wall, paste them and fold them in a concertina whilst they absorb the moisture from the adhesive.
- Start hanging across the top of the wall and work downward with additional each length.
- Do not hang a continuous strip around any corners, take each length around about 2.5cm (1 inch) and then butt-join the next strip.
Do not line the whole wall if you are just wanting to cover a small damaged area, such as damage from a removed dado/chair rail, hang lining across the damaged area and leave the edges hanging loose. Once the paste has dried, tear the edges back and sand them down to remove any “step up” from wall to lining paper.
You are now ready to go!
If you are unclear on any of the above or have any questions about your walls, feel free to contact us via e-mail including any images to show what you want to cover and we will get back to you with the best solution.
Reviewed 03/03/2023
Comments are closed here.