Wallpaper Seams Opening – Causes and Solutions

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 border adhesive in there. Click here to see some border 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 and 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.

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 manoeuvre 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.

How to Fix your Wallpaper Seams if they’ve opened

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.

The advice I’m about to give you will help if your wallpaper seams have opened because they have come unstuck. Follow these simple steps and you should be able to achieve your desired results with very little effort.

What will You Need

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. I’ll include links, but you can get all of this stuff from any DIY or Trade counter.

Olfa Knife.

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.

A vinyl smoother.

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 to avoid damage. Click her to see current prices.

Border adhesive.

In terms of border 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.

A cleaning sponge.

You will need to keep the face of your wallpaper clean, or it’ll mark. My link is to a proper cellulous sponge which has been specifically developed for cleaning wallpaper, but a household sponge will do for small repairs. – Click here to see online prices.

Steps

Open Your Wallpaper Seam

This may seem counterproductive, but you will need to access the back of the wallpaper to apply border adhesive. Slip your Olfa Blade into the seam and carefully tease it open until you have enough room to get the tip of your border adhesive squeezy tube in there.

Apply the Paste

Gently push the nozzle of your border adhesive into the wallpaper seam and extrude the material. Don’t use too much, or you’ll cause the paper to expand, and you’ll damage it.

Stick the Wallpaper Back

You may not want to do this straight away. As the wallpaper absorbs some of the moisture from the paste, it’ll become more pliable and easier to stick down. The trick is, not to rush it. Wait a couple of minutes after applying the paste, then try and stick it down. If it doesn’t cooperate, wait a couple more minutes and then try again. You should use a vinyl smoother to apply pressure to stick the paper. This will flatten everything down and spread the paste underneath.

Clean the Face of The Paper

Once the paper has stuck, simply wipe the face of the paper with a damp sponge. BE VERY CAREFUL NOT TO MARK THE PATTERN! You need to clean the paper without causing damage.

Don’t Overwork the Wallpaper

I know from experience that if you mess around with the paper too much then you’ll only make it look worse. If you’ve made your repair, let everything dry off (it often looks better once it’s dry). Don’t keep going back to it.

Final Thoughts

I hope and pray that if you’ve had wallpaper seams opening up, that this blog has helped. You can often fix the problem with a little bit of TLC, but just be careful not to further damage the paper.

If not, you’re probably looking at an expensive redecoration job. I can sympathise with this. Being a Professional Decorator, I know how frustrating a problem like this can be. At least now you have the information needed to avoid the problem in future.

FAQs

Is it normal to see seams in wallpaper?

This depends on the wallpaper you’re using. You can hide the seams when using some of the thick, good quality wallpapers that are on the market. However, it’s not always possible. Seeing the seams in wallpaper isn’t the end of the world, but seams opening up can be a disaster.  

Can you use PVA to stick wallpaper seams?

You can use PVA to stick wallpaper seams. However, PVA is very difficult to clean off the face of the paper, and neat PVA can peel off bare plaster. A specialist boarder adhesive is far more suitable.

Can you put the heating on after wallpapering?

Wallpaper paste drying too quickly can cause problems (as can wallpaper paste drying too slowly). We recommend good airflow but not too hot.

How do you camouflage wallpaper seams?

Sometimes you can colour wallpaper seams with a felt pen or pencil to camouflage them, but this doesn’t always work.