Paper-Hangings - Quality Products for the Professional Paperhanger

Rediscovering Wallpaper

By Robert M. Kelly

This article is about the nature of paper: why we use it for covering the wall, how we use it, how it reacts to water, and why it reacts this way. When I say "wallpaper" I mean just that. A traditional, unpasted paper, from companies such as Clarence House, Brunschwig & Fils, and Scalamandre. Most handscreens fall into this category.

This includes English paper like Cowtan & Tout. And it includes the most water-sensitive types of wallpaper, the French blockprints from Zuber and Mauny, and Chinese scenics, from de Gournay, Gracie, and others. What do these wallpapers have in common, besides being expensive, and sold through showrooms? They are mainly traditional, "real" paper, and require specialized techniques.

Ironically, we have now exactly the reverse of the situation in 1950 or so. Then, the great majority of wallcoverings were paper; they could be hung by rote, with a few specialized techniques required for the "different" product........vinyl. Now the situation is reversed. Vinyl is firmly in the mainstream, and wallpaper installation has become "different" and specialized.

Incidentally, the introduction of so-called nonwoven fibers into wallpaper is far from the revolutionary cure-all that some manufacturers claim. For example, nonwoven papers still expand – and contract. Granted, far less than traditional papers, but still, enough to cause concern.

If you want to make every installation with showroom quality wallpaper a successful one, you may need to "rediscover" wallpaper and learn about what makes it tick. This article would not have been necessary 40, or maybe even 20 years ago, but it is surely necessary now.

Today we have an entire generation of paperhangers who routinely (1) use a paint-roller or machine to apply thick layers of paste; (2) use pre-mix vinyl adhesive exclusively for unpasted material; (3) wash and roll seams vigorously; (4) use rigid vinyl smoothers to force the material tight against the wall and (5) never use blankstock lining paper.

You can hang the vast majority of vinyl and vinyl-coated products successfully with these techniques but if you use them with paper, you will, sooner or later, run into a serious problem with a room full of expensive paper. I guarantee it.

In almost every "problem" installation, the wallpaper arrives on the job with missing, outdated or contradictory guidelines. Paperhangers fall into their usual routine, outlined above. Sooner or later disaster strikes, and the reason is predictable: paper doesn't act like vinyl. It never has, and it never will.

The first step is to recognize that paper is radically different from vinyl. Paper is porous, vinyl is not. Paper will conform and adapt to pressure, vinyl springs back. Paper is easily bruised, vinyl is not. Paper needs a high-moisture low-tack system, vinyl needs a low-moisture, high-tack system. And we could go on.

The comments below about the nature of paper are offered as food for thought. I hope they help you "rediscover wallpaper" so that your business can grow and prosper when you find yourself facing a showroom quality wallpaper.

Why we use it for covering the wall

Wallpaper is flexible! Think about it, when an old plaster wall begins to belly out, not to mention a newly sheetrocked corner that is heading south, how can you hang a perfectly straight piece of anything on it! You can't! You have to be able to adjust the material to the wall. Traditional paper does this very well by stretching. With vinyls you have to double-cut or use a heat gun, duplicating the way that the vinyl sheet is formed in the first place, under extreme heat.

Here again we see that nonwovens are not a cure-all. While not as stiff as vinyl, they are not as flexible as paper, either. More important, they tend to return to their former shape after an overnight dry– this is not a plus when they've been stretched to achieve a perfect butt seam.

How we use it

Paper, at the microscopic level, is made up of bundles of fibers that have enough integrity to stay together, but enough "looseness" to absorb moisture; paper accepts a thin starchy paste readily, is easily adhered to the wall, and is able to absorb and carry inks, embossing, and other decorative effects without changing shape during the pasting and hanging process.

How it reacts to water

Paper expands when wet and fully relaxed, typically 1%. This translates into 3/8 of an inch for a 20 and 1/2 inch paper. This is normal, as is the slight contraction that takes place on drying. What is not normal are wild fluctuations in either expansion or contraction. These are product defects and should be recognized as such.

The challenge of installing paper is to anticipate the amount of future contraction, and to plan for it with correct wall prep and technique. This is where the blankstock liner comes in, to provide an optimum hanging surface that absorbs moisture quickly enough to set the seams before they have a chance to pull apart and split.

Why it reacts this way

Paper needs water to relax because, unlike vinyl, it is not supple in and of itself. But while it needs water, it needs only a certain amount. Some showroom wallpapers are colored with sensitive inks that can be damaged by oversoaking or overworking the seams.

The best analogy I can think of is the proper procedure for making french toast! You don't soak the bread in the batter until it's completely saturated and falls apart. The batter should sink into the bread only partially. In the same way paste should sink only partially into the paper, just enough to relax it thoroughly. Soaking a paper excessively is an invitation to "strike-through" - this is when the moisture comes all the way through to the face. "Strike-through" can damage the inks, resulting in shading or spotting.

Incidentally, nonwovens are not immune from strike-through. Indeed, the ones that have fewer ground coatings and protective coatings are more vulnerable, because there is little to stop the paste from wicking through.

Conclusion

The fact that wallpaper needs water to relax explains why a high-moisture paste such as wheat or cellulose is preferred. Even a clear premixed vinyl, which contains about 75% water in the pail, needs to be knocked back quite a bit to fully relax the material. The moisture content of a paste should be closer to 90% for paper. Because it absorbs so much water so quickly, paper may need to be double-pasted. The first pasting begins the process, and the second pasting (usually much lighter) equalizes the paste layer.

Sweeping a strip of paper to the wall does not require the pressure needed for vinyl. If the paste is the correct consistency, and if the face of the paper is still porous, expansion bubbles will dry out by evaporating through the face of the paper; they do not have to be forced out. This is especially true if blankstock is used, because it blots up moisture from the back side as well.

Every installation for the high-end designer trade needs to be approached cautiously and with respect. Designers and customers are ready to demand a high level of proficiency, and rightfully so, as the material is always expensive. When getting involved in a job of this type, take your cues from the nature of the paper itself. Test it, and observe the results; listen to what the paper is telling you. This is the best and perhaps the only way to make every wallpaper installation a successful and profitable one.