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The Showroom Handbook

Preface

        This handbook exists to fill a need. Guidelines for installation of the higher quality wallpapers at the showroom level are difficult to find. Although there is a lot of technical material presented, this is not a "how-to" book. Nothing can replace the skills of an experienced professional paperhanger.

          It is a premise of this handbook that with enough information and planning, every showroom wallpaper installation can be brought to a successful conclusion. This book assumes that the installer is already experienced with wallcoverings, and that additional information specific only to wallpaper will be helpful. The true purpose of the book is to promote better harmony between the installer in the field, the designer, and showroom personnel. The better quality papers deserve a cooperative effort from all the professional fields involved in their use.

          Designers and showroom personnel need specific information about fine wallpaper, because it is they who are on the front lines when questions arise. The simple truth is that there are dramatic differences between wallcoverings sold at retail and wallpapers found in showrooms.

        Traditional wallpapers require careful wall preparation and specific types of paste. The techniques of trimming, pasting, sweeping and seam-rolling are different for showroom quality wallpapers than for more durable wallcoverings. One of the problems brought on by the lack of information is that guidelines meant for one type of wallcovering are sometimes misapplied to another; this cannot fail to cause problems, because different wallcoverings must be handled in different ways.

        This handbook aims to provide as much detail as necessary for the situation at hand, in an easy-to-find format. It includes a set of generic guidelines (Chapter 9), solutions to the "top ten problems" (Chapter 7), and a chapter on estimating (Chapter 6) as well as chapters on the major showroom types: handprints, imported machine prints and blockprints.

          This handbook is dedicated to the quality producers, printers and sellers of showroom quality wallpaper, without whose support it would not have been possible.

Chapter 1: A Paper Primer

This chapter is about the nature of traditional, unpasted wallpaper, and gives the reasons why installation of these papers must be different from the installation of vinyl types.

Defining "Wallpaper"

         The world of wallcoverings is a world of variety. There are probably as many as a hundred different types, printed on dozens of different substrates. This handbook discusses only showroom quality blockprints, domestic handprints and imported machine prints. For the purposes of this book, only these 3 will be defined as "wallpaper" to differentiate them from other types.

        Many wallcoverings sold at retail could reasonably be classified as wallpaper because their substrates are paper-based. And there are many wallcoverings sold in showrooms that could be classified as vinyls; screenprinted paperbacked vinyls for example. However, this handbook seeks to draw a basic distinction between the paper types (which are most often found in showrooms) and the vinyl types (which are most often found at retail).

          All of the traditional papers described in this book have certain qualities that set them apart from vinyls and vinyl-coated papers.

Traditional papers are:

  1. usually highly porous on the back side.

  2. usually breathable on the front side.

  3. often undergo a color change when pasted.

  4. often delicate, compared to vinyl types.

  5. usually unpasted.

DEFINITION: The term "wallpapers" as used in this book describes the finer quality unpasted papers which are porous on the back side and relatively breathable on the front side.

Papers and Vinyls

        Wallpapers, at the microscopic level, are made up of bundles of fibers that have enough integrity to stay together, but enough "looseness" so that they become flexible when pasted. They readily accept a starchy paste and are easily adhered to the wall. During the pasting, hanging and contraction process a great deal of stress is put on the paper, which in turn puts a great deal of stress on the wall. This is why correct wall prep is so important.

        All of the traditional paper types in this book are, to a greater or lesser degree, water-sensitive. Although they are usually hung with a high-moisture paste, they need only a certain amount, and can be damaged by excessive amounts of paste, the wrong type of paste, or incorrect hanging techniques.

        The more a wallpaper is coated with ink, the less it "breathes" (allows moisture and air to escape through the surface of the wallpaper). The more that a wallpaper is coated, the more it tends to behave like a vinyl. Still, wallpapers will eventually "wet out" (become fully expanded) while vinyl types generally have no need to relax as fully.

           Many of today's installers, trained on vinyls or vinyl-coated paper, are unfamiliar with the requirements of traditional wallpaper. This is true whether the product is a traditional European paper or a top-of-the-market domestic handprint. Vinyl types are made to be durable; they are washable, and may even be scrubbable. Wallpapers, on the other hand, are delicate; they need a soft touch during installation.

           Wallpapers accept a lot of moisture during the pasting process. They expand, always across the grain (width) and contract somewhat as they dry. Because their surfaces "breathe", they allow moisture and air to escape, whereas vinyl types are likely to trap both moisture and air.

            Of the three types discussed in this book, domestic handprints are the least "paperish" because they are usually printed on a strippable substrate. This type of backing is composed of paper which has been strengthened by the addition of resin binder. The inks used, either solvent-based or water-based acrylics, also make them less breathable than the other two types.

The Installation Cycle: Paper Types

        Let's take a quick look at what happens when a typical wallpaper is pasted. First, a high-moisture paste is applied to the back of the paper. Almost immediately, the paper begins to buckle as the fibers expand at different rates. After 5 minutes most papers are fully expanded, and the width of the sheet begins to equalize. If the paper stock is thick and porous, double-pasting may be necessary to fully coat the back of the paper. The paper may tear easily, and "booking" (folding) the sheet must be done carefully.

        Meanwhile, changes occur to the front of the paper. A darkening "blush" may appear as the moisture begins to affect the inks. Depending on the amount of penetration, this may spread into a full-blown color change throughout the sheet. The paper when fully expanded is limp, relaxed, and cool to the touch.

        During installation, the paper is flexible; it can be pushed or pulled as necessary to make a butt seam to a neighboring strip. Once the strip is swept down against the wall with a soft bristle brush, the paper immediately begins to lose moisture. Not only does moisture from the paste begin to sink into the wall, it also begins to evaporate through the face of the paper into the air. The sheet begins to look blotchy as the colors dry and lighten.

         Ideally, within about 10 or 15 minutes, the sheet of paper is ready for seam rolling with a wooden seam roller. This will set the seam and the installation is complete. There is usually a slight contraction of the seam during drying.

How does this differ from the vinyl types?

The Installation Cycle: Vinyl Types

        First, a minimal amount of a high-tack, low-moisture pre-mixed vinyl adhesive is rolled onto the back of the sheet. Ordinarily, neither buckling nor color changes take place; some slight expansion may occur. The sheet can be brought to the wall quickly. Alternately, it can often be dry-hung (the wall is pasted and the vinyl installed directly on the wall). The product does not tear easily, and booking is done quickly.

        Solid vinyls are most often pressed against the wall with a short synthetic bristle brush, or a solid vinyl sweep (rigid plastic). No air is allowed to remain between the wallcovering and the wall because after installation it might remain as a blister under the vinyl film.

        The vinyl can be moved slightly during installation but it may not stay in place because it has a "memory": it returns to it's former shape. The vinyl is not limp, is not relaxed, and is not cool to the touch. Only by using a heat gun can vinyl be made as flexible as paper. The extreme heat imitates the manner in which it was formed into a sheet.

        Vinyl types are ordinarily rolled vigorously with rigid seam rollers; hard plastic and steel are the norms. The sheets will not dry out, under the best of conditions, for about 12 hours. This explains the necessity for a high-tack, low-moisture paste that will hold the vinyl in place with "wet tack". There is only very slight contraction during drying.

What conclusions can we draw from the differing installation cycles of paper types and vinyl types?

        The most important lesson is that the properties of paper types and vinyl types are so different that they call for two different installation systems. We can generalize to say that paper types demand an "open" installation system based on high-moisture pastes, very porous backings and breathable surfaces, whereas vinyl types demand a "closed" installation system based on low-moisture adhesives, less porous backings and impervious surfaces.

 Let's look at three areas of the "open" installation system in detail:

                        1.) Pasting
                        2.) Installation
                        3.) Expansion and Contraction.
               

1.) Pasting

        Wallpaper needs moisture in order to relax. A flexible sheet is necessary not only to make a good seam, but also to follow the contours of the wall. But while paper needs moisture, it needs only a certain amount. Many showroom wallpapers are colored with sensitive inks that can be damaged by oversoaking the sheet.

          Wallpapers should be evenly pasted, just enough to relax them thoroughly. Type, amount, and thickness of paste may need to be adjusted for the paper at hand.

2.) Installation

        Because it is much more porous and breathable, paper types do not require the same degree of pressure during installation as vinyl types. If the paste is the correct consistency, and if the face of the paper is still breathable, excess paste will dry out naturally and small expansion bubbles will tighten to the wall; they do not have to be forced out.

        While vinyl types can remain moist for extended periods of time without damage, the same cannot be said for paper types. The drying cycle for paper should be as short as possible; the installer's goal is to use correct wall prep so that the paper dries out quickly and uneventfully.

3.) Expansion and Contraction

        Wallpaper expands when wet and fully relaxed, typically 1%. This means that a 20 and 1/2 inch paper will expand to 20 and 7/8 inches, and that a 27 inch paper will expand to 27 and 1/2 inches. This is perfectly normal, as is the slight contraction that takes place as it dries. Vinyl types do not expand this much, nor do they contract as much as the paper types.

          The challenge of installing wallpaper is to anticipate the amount of contraction that will take place, and plan for it with correct wall prep and technique. An ideal surface is one that absorbs moisture quickly enough to allow the seams to be set before they have a chance to contract; if left unchecked, the contraction can result in a "split seam". Blankstock liner provides an optimum hanging surface for wallpapers.

Conclusion

        In many "problem" installations, the wallpaper has arrived on the job with missing, outdated or contradictory guidelines. In the absence of guidelines the paperhanger may resort to hanging a paper type with vinyl type techniques, as outlined above. When confronted with a "problem" installation in progress, the first question should be whether the installation techniques are matched to the type of wallcovering at hand. Testing of the paper by installing small samples on a prepared wall may be necessary to verify type.

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