How to Trim and Cut Wallpaper: Tools, Approach, and Tips

If you want great looking wallpaper, you can’t forget the finish work. It may seem straight forward but getting perfect cuts along your ceilings and floors can be tricky depending on the type of wallpaper being hung. We cover the tips, techniques, and tools you need to achieve crisp, clean lines along your cuts.
Scissors creating a relief cut in wallpaper around a window.

You can avoid these common mishaps and achieve great results by following these tips:

Cutting Wet And Dry Wallpaper

Dry Wallpaper

Dry wallpaper is naturally stiffer, and easier to cut with scissors or a snap-blade knife. The reason is that dry wallpaper has more resistance to the sharpened edge of the blade, which allows the cut to be smooth and straight. If you have ever cut brown wrapping paper with a pair of scissors you may recall that once you started the cut, you could push the scissors straight across the paper without opening the blades any further. Most dry wallpaper will respond in a similar fashion.

Wet Wallpaper

Once the paper has been wetted with adhesive, it is now limp and offers zero resistance. This will make it nearly impossible to make the same cut described above without tearing the wallpaper to shreds. Wet wallpaper must be cut with very sharp scissors or a snap knife with a fresh blade in order to avoid damage.

Making Relief Cuts Around Doors And Windows

Most of the time, cuts for doors and windows are made after the wallpaper has been wetted with adhesive. These cuts are extremely delicate because part of the panel is still sticking to the wall when the trim cut is made. The ideal tool to use for this operation is a very sharp pair of scissors.

The wallpaper should have been cut allowing two inches to remain inside the door or window opening. This excess will be cut away after the panel has been placed on the wall.

When cutting a 90-degree angle around door or window trim, make a pencil mark at the outside point of the angle. Lift the paper away from the wall and using a pair of scissors, cut an angle back to the mark. Do not overcut or you can cause tears when the paper is smoothed out.

Gently push the paper back over the corner, and using a smoothing tool, crease the excess wallpaper along the trim on the side and top (or bottom) of the window or door. Using a fresh blade in the snap knife, remove the extra paper by running the blade down the edge of the smoothing tool in the crease.

Another area that will require the use of scissors is cutting around circles or oblong shapes. If the paper is wet, the only safe way to make these cuts is with a pair of sharp scissors.

Trimming The Top And Bottom Of The Panel

The initial cut of each main panel should allow two inches of overlap at the ceiling and the baseboard. If the wallpaper has a pattern, it may be wise to hold off trimming the top and bottom until all of the panels are installed. If there is a need to move the paper to keep the pattern match correct, this extra length could be helpful.  Once cut, you cannot move the panels without leaving visible errors.

Once you are certain it is safe to trim the wallpaper, run your smoothing tool along the angle where the wall meets the ceiling and top of the baseboard, making a crease.  Leaving the smoothing tool in the crease, take your snap knife and trim the excess paper.

Double Cutting Seams On Commercial Projects

One of the more complicated cuts required in hanging wallpaper is the double cut. This is required whenever overlaps occur, especially on inside and outside corners and murals. The risk in making this cut is that the blade will go too deep and cut into the face of the drywall below the wallpaper. Once the surface of the drywall has been slit, moisture will get in and the paper face will start releasing which will eventually make the seam fail. 

There are a couple of products on the market that can help eliminate this problem, but the best is a seam buster. It has a protective shield that keeps the blade from cutting into the drywall while allowing it to cut through all the layers of the wallpaper. Commercial wallpaper hangers will find this invaluable tool to be a game changer, helping them make safe cuts that won’t invite unwanted callbacks down the road.

Snap-Blade Knives vs. Utility Knives

Any knife used for cutting and trimming wallpaper needs to have a new blade for every cut to ensure there are no tears or rips. Paper dulls a knife blade, so in order to have the best edge available with a standard utility knife, you would need to change the blade on every other cut. The snap blade, or snap off knife has simplified this procedure, providing a fresh blade by pushing down on the old blade and snapping it off. There’s no need to stop working so you can find a screwdriver to take your utility knife apart in order to change the blade.

ROMAN – The Best Wallpaper Hanging Products

Whether you are hanging wallpaper in your home for the first time or you are a seasoned professional, ROMAN Products has the removers, primers, adhesives and tools to help you get the job done right the first time. Our products are available worldwide and can be purchased in your local hardware store or ordered online. 

Contact us today for specific recommendations that will make your next wallpaper project picture perfect!