FAQ--Frequently Asked Questions About Wallpaper

The following list of frequently asked questions has been compiled from many years in the wallpapering business and from e-mails that come to me through this web site. I also write a column on wallpapering for Painting and Wallcovering Magazine and some of these questions are linked to those columns:

When should you prime walls before wallpapering?
By far, this is the most common question with many variations like: Should I prime on plaster?, Should I prime on new sheet rock? or,  Do I need to prime when the wall is already painted? Priming is the most important step in any wallpaper job-- whether it is a professional or amateur job. There are instances where priming the wall is not necessary but those instances are rare. It really takes the experience of a professional paperhanger to know when to prime and when not to prime. If you want to know more about this subject in depth click here.

How do I remove wallpaper paste from the wall?
Wallpaper paste is removed with hot sudsy water, a scraper, and time to let the water work and soften the old paste. A steamer is really not necessary; a pump-up 2 gallon water sprayer does just fine. Chemicals are not necessary to soften starch either. Starch is the main ingredient of all wallpaper pastes and it softens after a soak time of from 15 to 30 minutes. Sometimes white vinegar helps to speed up the job. Some people think that you should use sandpaper to remove the paste but that really doesn't do the job --you simply end up sanding off the flaky bits of paste but you don't remove the paste glaze that is on the wall. That paste glaze can interfere with later priming. Washing the wall squeaky clean is still the best way to go.

How do I remove old, dried wallpaper paste that is on the wallpaper surface?
The best way to deal with wallpaper paste on wallcovering is to not get it on the surface in the first place. If you are a do-it-yourselfer, make sure to wipe down the wallpaper sheets several times with clear water during the hanging process. If you (or a careless paperhanger) got paste on the surface you should place a paper towel over the dried paste and spray the towel with Windex. (Do not let the Windex drip down the wall from that spot.) Let it soak for 10 minutes or so and carefully dab the spot after the paste has softened. Be advised that some wallcoverings, particularly dark papers, will "burnish" or leave a shine mark if you rub. The best way to proceed with this type of cleaning is to get a test piece if possible before you attempt to clean a surface.

Why does an English pulp paper need blankstock lining paper?
Designer papers like Sanderson, Osborne & Little, Cole & Son, Farrow & Ball etc. not only require a plain paper underlayment before they are installed, they also need special adhesives. Here's why these papers need blankstock and here's why they need special adhesives.

My prepasted wallpaper doesn't stick what should I do?
This question has other related questions like, "Should I add paste to my pre-pasted wallcovering?"  Manufacturers have gotten much better at putting pre-pasted adhesive on the back of their wallcovering. Years ago it was not uncommon to have long sections in a roll of pre-pasted wallpaper that had no paste on it at all. For that reason paper hangers got into the habit of adding paste to pre-pasted wallcovering. If you are having trouble making your wallcovering stick to the wall, go to the paint store and get a premixed wallcovering adhesive. Thin it down to the consistency of V-8 Juice and apply it to the back of your wallpaper.

How long does it take wallpaper to dry/In Bathrooms: Can we shower soon?
There are many different types of wallcoverings and there are many different types of walls, so there is no single answer to this question. Generally speaking, most wallpapers dry overnight. However, in the case of older buildings that have multiple coats of glossy paint on the walls, the drying process can actually take weeks. The important thing for customers to remember is that while wallpaper is wet it can rip more easily, so care should be taken with furniture and wall hangings as you move everything back into place. In the bath, you can shower immediately with almost any type of wallcovering-- just make sure to use the exhaust fan or leave the door open. Don't allow steam condensation to build up in the room while wallpaper is drying.

Can I hang wallpaper on new plaster?
Nowadays when people say "new plaster" what they really mean is new joint compound or some other gypsum-type patching compound. Old-fashioned lime plaster is rare, but whatever the patching material is, the most important thing is the thickness of the material. Deep areas of patching or deep whole-wall skim coating contain a lot of water and it takes a long time for the water to completely dissipate even though the surface feels dry to the touch. For thick patching compounds, the best way to tell if the water has dissipated is to buy or rent a moisture meter.

Can you prime over old paste?
It is not a good idea to prime over old paste. Most of the time the old paste will come off with hot sudsy water and elbow grease anyway... especially if the wall was well-primed before the wall paper was put up. When the wall was not well-primed before the old wallpaper was put up, you will notice that the old paste has usually become combined with the latex paint on the wall. If the paste will not wash off the old latex paint by scrubbing with a plastic pot scrubber and hot water then you are dealing with a combination of dried paste and paint and, yes, you can prime over that surface.

Can you hang new paper over old?
Many years ago wallpaper was routinely hung over old wallpaper. But in recent decades most wallpapers have a vinyl coating or are sheet vinyls which makes them a vapor barrier. Attempts to cover one vinyl material with another vinyl material will likely result in mildew forming between the two layers. Also many newer wallcoverings are not completely opaque so the underlying pattern could show through.  Other times the underlying wallcovering will bubble.  Hanging over an old material is a gamble.  All wallcovering instructions say to remove any old paper so if you have a problem you are on your own.

Can you paint over old wallpaper?
Yes and no. If the material is a sheet vinyl like fabric backed wallcovering or paper backed sheet vinyl, you can paint it because the paint will be adhered to the vinyl sheet when you yank it off the wall at a later time in the future. But materials that are not designed to be dry yanked off the wall (see "Types of Wallcovering") like those types which need soaking will become fused to the wall. The coat (or two) of paint will prevent penetration of the soaking water used for removal.

Why do seams shrink?
A lot of time could be spent on this question and we would still not cover everything. What I can tell you is that many times seam shrinkage is caused by the over application of wallpaper adhesive. Many paperhangers think that more is more when they should be thinking that less is more. Another cause of seam shrinkage is improper booking time of wallpaper sheets. Unfortunately the proper booking time is determined by material and adhesive type and this is an area of expertise that requires some years of experience. Another common cause of seam shrinkage is when a wallpaper installer rolls the seams too soon. This early rolling action forces paste away from the seams because the paste is still viscous and squeezes out from the seam area. You should wait at least 2 hours before attempting to roll seams, many times more than 2 hours.

Can I remove wallpaper with a propane torch?
That's a scary question.

What's the best way to hide rough walls and wall cracks with wallpaper?
There used to be an old saying, "to wallpaper over your problems." Nowadays many wallpapers are so thin that professional paper hangers needs to prepare and smooth the wall as if they were preparing to paint. If you read my "Types of Wallcoverings", make a note that fabric backed vinyl is the best material type for covering up rough walls or cracked walls--- especially if the fabric backed material is heavily embossed and matte in finish. If the walls are really bad there are many different types of liner papers which act as an underlayment and pad the wall. Lining the walls to take care of roughness requires either polyester spun liner paper or thick non-woven liner paper. Nowadays grass cloth has become popular again and I don't think there's anything better than natural, thick grasscloth to cover up rough and problem walls.

Why do I get white seams when using dark wallcoverings?
Many manufacturers make their dark wallcoverings on white ground paper. When you look at the edge of the dark paper from a sharp angle you see a white edge-- even if the seams are well joined. Most professional paperhangers color the seam edges in some way. There are many different techniques for this process. Personally I prefer to color the seams after the wallpaper has been hung and the seams are dry.

Should you prime the walls dark for a dark colored wallcovering?
Rarely. A good, regular wallcovering primer will do just fine. I wrote about this more in depth in Painting and Wallcovering Contractor Magazine if you want to know more.

What effect does humidity have on a wallpaper job?
Humidity has an effect on most wallcoverings, primers and adhesives. There has been much concern in recent years over the growth of mildew behind wallcoverings. The news media in many cases have become hysterical about the issue. But the problem of mildew growth is mainly a problem of a very small area of the United States-- the Gulf Coast. Even in that small area the problem of mildew growth can be overcome with breathable type wallcoverings, not solid-vinyl sheets. The best type of wallcovering for high humidity areas remains fabric backed wallcovering. By high humidity areas I am referring to the source of the humidity being inside the house, as in bathrooms, not outside the house as it is on the Gulf Coast. Fabric backed wallcovering has the ability to withstand extended periods of shower moisture over the years and it is the most scrubbable and the least prone to exhibit seams splitting or seam loosening under high humidity conditions.

How can I get perfect seams when wallpapering?
The same way you get to Carnegie Hall.

Why do British papers cost so much more to hang?
British pulp papers like Sanderson, Osborne & Little, Cole & Son, require the extra step of blankstock lining. What this means is that the room must first be wallpapered with a plain manila colored paper. The paper must then dry, usually overnight, so even a small room that normally takes one day becomes a two-day job. Also there is an additional material expense of the blankstock paper usually supplied by the professional paper. More on the use of blankstock lining.

How do you remove wallpaper?
The game of golf consists of hitting a ball in a hole and act of removing wallpaper means ripping off wallpaper from a wall. What could be simpler? But the truth is that there are many techniques for removing all the different types of wallpaper materials. Sometimes the job is very easy as it usually is with fabric backed vinyl. However there are instances where someone put up wallpaper on an unprimed wall and even the most seasoned wallpaper remover will start cursing. Generally speaking, fabric-backed wallcovering and non-woven wallcovering gets pulled from the wall while it is dry. With paperbacked vinyl, the vinyl part gets pulled off the wall and the paper backing gets soaked with water and then scraped. All other types of materials like paper, lightly vinylized paper, grasscloth, and other natural fibers must be soaked with water and then scraped.

Can grasscloth be used in a bathroom?
If it is a small bathroom where a lot of humidity builds up the answer is "no." If it is a full-length powder room or bathroom where the grasscloth is close to a toilet bowl I would definitely say the answer is "no." Grasscloth is absorbent and cannot be cleaned with any type of standard bathroom cleaner. Most instructions that come with grasscloth advise that all you can do to clean it is to use a vacuum cleaner. However, if you're referring to a very large bathroom often found in today's extremely large houses where moisture never builds up and the walls are never touched, you could probably get away with putting grasscloth in a bathroom if you keep the room dry.

How do you match grass cloth wallpaper?
You don't. Natural grasscloth, the non-dyed type, is not designed to be matched. Even the dyed type almost always has a disclaimer accompanying the rolls which says," Don't expect this material to be uniform in color." Here is a picture of a natural grasscloth and here is one of a dyed grasscloth.

How do you hang grasscloth?
Here is an in-depth article I wrote for PWC magazine Jan/Feb 2008 on hanging grasscloth.

How do you hang old retro wallpaper?
Very carefully. Old wallpapers can be weakened by acids within the paper. They also may require special trimming (if the pattern permits} because the outer edges of the role may have discolored over the years. If you are out at a flea market or in an antique shop and you see a retro wallpaper, figure on buying much more than you actually need because a lot of it may end up in the garbage.

Can regular paint be used to prime new sheetrock for wallpapering?
No. Never. You must use a wall protecting type primer designed for wallcovering.

What's the difference between sizing and priming a wall?
Here's a short article on the subject.

How do I hang wallpaper in a two story hallway?
This requires scaffolding which you can rent. I don't consider two story or three-story hallways to be the domain of do-it-yourselfers. If you really feel comfortable manipulating a 16 foot-long piece of wallpaper as you stand 10 feet above the ground you probably should become a professional paperhanger. Otherwise I suggest you call a professional paper hanger for any sort of job of this magnitude.

What causes wallcovering to bubble?
The most common cause of wallpaper bubbling is improper booking time. Wallpaper must have several minutes or longer to soak up the water in the paste and expand. Different types of wallcovering adhesives can also affect the time it takes for the paper to soak up the water in the paste.

Is there a plain wallcovering I can to cover up rough walls or even cinder blocks?
There are many different liner papers on the market today which can handle rough walls, stucco walls, or walls that have been coated with "knockdown" finishes. These liners range from the wall resurfacing types to lightweight underlayments for slightly rough walls. A professional paper hanger can advise you on which type of wallliner is right for your walls. It also doesn't hurt to test hang a small section of wall with the proposed liner paper and on top of that the proposed pattern paper hung and allowed to dry. Three good sources: (www.wallliner.com for regular bridging liner and blankstock , Ultratap Block Liner www.roosintl.com for medium rough walls, Plaster in a Roll from Flexi-Wall Systems for really thick liner www.flexiwall.com

Where can I get mildew proof wallpaper paste?
There is no wallpaper paste that is mildew proof. All wallpaper pastes are made out of starch. Mildew loves starch under certain growing conditions. Most of the mildew inhibitors in the paste are put there to prevent mildew from growing in the can on the paint store shelf-- not to be resistant to mildew growth after the can is open and the paste is exposed to the environment.

What is the best primer for pasting wall paper on wood paneling?
Almost any good wallcovering primer can be used on wood paneling. Before applying the primer you should wash down the wood paneling to make sure that no wax, Pledge, or Olde English has been used on the surface. I like to use not too sudsy hot water with a cup of ammonia in the bucket. After that a quick wipe down of the surface with mineral spirits should get any residual greasiness or old Pledge. I used to hang a lot of wallpaper on paneling in the 1980s, but after seeing several incidents of "stressing", my advice to customers nowadays is not to do it. Wood paneling is very much subject to changes in dimensions throughout the seasons from summer to winter and the paneling can put stress on the wallcovering hung over it. This stress is exhibited by stretch marks where the seams of the paneling meet. I have even seen this occur after all the seams of the paneling were screwed down every couple of inches. My advice for someone who wants to wallpaper over paneling is to remove the paneling.

Should I use an oil-based wallcovering primer?
Good luck finding an oil-based wallcovering primer. Government regulations have forced paint manufacturers to discontinue most of these products. Many instruction sheets that accompany your wallpaper rolls call for an oil-based primer. Unfortunately those instructions are now out of date. Your best bet is to find a wall-protecting, white acrylic wallcovering primer.

For Professionals-- The Hohlenpoker Page