Wallpaper Seams Opening – Causes and Solutions

Updated Feb 14, 2024 | Posted Feb 1, 2020 | Professional insight, Miscellaneous | 1 comment

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.

 

Seams Opening on Non-Woven Wallpaper

Preparation

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.

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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.

 

Stretching

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.

 

Seams Opening on Pulp Wallpaper

Oversoaking

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.

 

Stretching

Yes, this can happen for either type of paper. Do not over work your paper or use excess pressure to move it into place.

 

Paste

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.

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How to Fix your Wallpaper 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.

 

What will I Need for Tackling Open Wallpaper Seams

 

I thought I’d put together a little list of tools you might use to fix the issue of wallpaper seams opening. This section is based on my own preference regarding brands, but they’re inherently trade-quality products, and I fully endorse all of them.

You might use a knife to slice the paper and open the seam wider so you can get wallpaper paste behind it. The best wallpaper knife on the market is Olfa. These snap blades are made in Japan and stay razor sharp for multiple cuts. Click here to see current prices.

You may also need a vinyl smoother. Something small and soft enough to manipulate the wallpaper without damaging it further. Coral is probably the best, and it’s cheap! It has rounded corners which helps when avoiding damage. Click her to see current prices.

In terms of boarder adhesive, there are plenty of generic brands that will probably all do the same job. Go for one of the ones in a squeezy bottle because you’ll find it easier to push the glue into the wallpaper seam. Solvite is a good shout. It’s a great product at a reasonable price. Click here to see current prices.

The only other things you might need are a sponge and some felt-tip pens.

Wallpaper Seams Opening – Causes and Solutions – by Mike Cupit

Updated Feb 14, 2024 | Posted Feb 1, 2020 | 1 comment

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1 Comment

  1. Paul Williams

    Another helpful tip when pasting papers is to fold then roll the paper to avoid edges curling up

    Reply

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