There is nothing more annoying than finishing the decorating in a room, then coming in the next day to see the wallpaper seams opening. As a professional decorator I have seen this problem many times. A lot of the time it is completely avoidable. In this blog I’ll take you through some of the causes and offer a solution or two.
It is important to understand exactly why the wallpaper seams have opened. The paper itself has shrunk slightly after you have installed it, causing the seams to open. Either that, or the paste just hasn’t stuck, in which case get off the internet and just get some boarder adhesive in there. Click here to see some boarder adhesive.
There are two different types of paper, pulp and non-woven. The difference is you apply paste to the back of a pulp paper and allow it to soak. As you do this the paper expands and becomes easier to use.
Non-woven papers can be applied directly to a pasted wall. These do not expand and therefore will not contract if you get the decorating right.
Let’s go through the possible causes for seams opening on each type of wallpaper.
Walls should always be lined prior to installing non-woven paper as the paper itself does not absorb any excess paste. The lining paper will also expand slightly as you apply the additional paste, then contract and tighten as it all dries out.
This will also help to keep your wallpaper tight prevent seams from opening up.
The correct paste –
You should use a cellulose based, or ready mixed paste for non-woven paper, as this type of paste tends to be a bit grippier and contain a low water content. If you use the wrong paste, you risk the paper being able to move as it dries. If in doubt, check the manufacturer’s instructions. Beeline red-top is often a safe bet.
As mentioned, non-woven papers do not absorb paste and expand like pulp papers do. Therefore, the only way the paper does expand is if you stretch it on application. Do not paste the paper, there is no need. Paste the wall and get your paper up. Once it is on the wall do not use excess pressure to maneuver it. If you do stretch the paper, it will contract and you will see your wallpaper seams opening as your paste dries.
You do need to apply your paste and allow to soak so your wallpaper expands. However, only leave for the recommended soaking time. Any longer and you run the risk of your paper contracting once on the wall and seams opening. Similarly, don’t rush anything either. If the soaking time of your wallpaper is 10 minutes, wait 10 minutes before you hang it. If not, the paper will carry on expanding on your wall and the seams will overlap, or push themselves open.
Yes, this can happen for either type of paper. Do not over work your paper or use excess pressure to move it into place.
Normally starch based (packet mix), for lighter papers. Anything slightly heavier and you should lean towards ready-mixed. The brand leader when it comes to ready mixed wallpaper paste is Beeline, which I’d highly recommend.
How to Fix your Seams if they’ve opened
There are a couple of possible solutions. If your seams have opened because they have come unstuck, then all you need to do is use some border adhesive. It doesn’t cost much, it’s easy to use, and it’s cheap. You can pick border adhesive up at any good trade paint outlet, or online by clicking here. Just be careful to wipe any excess off the face of your wallpaper.
If your seams have opened because your wallpaper has shrunk, then you may have a problem on your hands. There are only really two solutions; you could strip the wallpaper and start again. Or, why not colour your seams with pencils. Sometimes it works, sometimes it doesn’t. Don’t press hard and use a similar colour to your finish paper.
Wallpaper Seams Opening – Causes and Solutions – by Mike Cupit
Another helpful tip when pasting papers is to fold then roll the paper to avoid edges curling up