The Use of Bridging Material Over Irregular Surfaces
By Rebecca Schunck
Rebecca Schunck is a paperhanger based in Virginia Beach, VA. Member of the NGPP and forum moderator for wallpaper on www.doityourself.com.
The material, for which I speak, is known by many names throughout the wallpaper industry. It is known as bridging material, wall liner, lining paper, and liner paper. For the sake of this article, I will refer to it as bridging material.
Bridging material is a porous under-wallcovering material designed to cover irregularities on walls or smooth surfaces, such as brick or paneling, to hang decorative wallpaper. Woven or non-woven (spun), either synthetic or a blend in composition. This material may also be painted though many hang regular wall liner or float joint compound over the bridging material for a smoother surface.
Bridging material was designed to cover surfaces that normally would require the expensive services of drywall or plaster contractor. The surfaces it can cover are limitless, but the most popular are:
Preparation prior to the application is the key to a successful installation of bridging material. Slick surfaces should be sanded with 200 grit sandpaper. Next comes a cleaning with TSP (TriSodium Phosphate) or equivalent grease cutting cleaner. Paneling should be checked carefully for loose panels, popped nail heads, or miss-aligned panels. With paneling, you may also take the extra precaution of filling in the seam areas with joint compound, though this isn't entirely necessary. All of these discrepancies should be corrected prior to the cleaning steps.
Physical preparation is just as important as the selection of the proper primer for use prior to installation. Primer determination is broken into two parts. Slick or non-porous surfaces and dull or porous surfaces.
Slick surfaces will require the application of a primer/size, also known as a prep coat. This is a special type of primer that after the proper curing time, retains an extremely tacky surface texture. You should consult your local paint store for availability. Manufacturers include Roman's R-35, Zinsser's Z-54, California Paint's Prep 'n Size, Golden Harvest's BITE, Muralo's Adhesium, Duron's Tack Prep, and Benjamin Moore's Wall-Grip.
Porous surfaces will require a primer that is suitable for the surface worked upon. Your local paint store can provide recommendations based on the material. If you plan on installing bridging material on brick, cement block, damaged drywall, or any surface facing an outside wall (such as a finished basement), you should consider applying a primer/sealer. Primer/sealers are new products that even experienced paint professionals have little knowledge about. The were originally designed to seal concrete and were found to have the same results on drywall. Manufacturers include: Scotch Paint's Draw-Tite, Zinsser's Gardz, Roman's Liquid Drywall, Seal-Krete's waterproofing sealer, and Sherwin Williams' PrepRite Drywall Conditioner. Ensure that you purchase one of these particular brands. Many paint manufactures apply the "primer/sealer" tag-line to their products as a marketing tool, when the above listed products are the true primer/sealers.
Your next step is the application of the bridging material itself. It installs the same as regular wallpaper. This can either be performed by a professional or by the homeowner. A quality wallpaper adhesive should be used during the installation process. Any of the major wallpaper adhesive types may be used: clay, wheat, clear, or vinyl. For best results, clay professional strength vinyl adhesive is recommended. Manufacturers of these adhesives include: Gardner-Gibson, Roman Adhesives, and Zinsser. These may be obtained at local home improvement and wallpaper stores.
Wallpaper adhesive should be applied using a paint roller to cover the back of the material and allowed to book (rest) for five minutes. To book the product, fold the material paste side to paste side without creasing. Then you will apply and trim the material just like wallpaper.
Bridging material requires at least 24 hours to dry, sometimes longer depending on humidity in your area. Once dry, the bridging material is ready for the application of a finish wallpaper or painting. If additional wallpaper is used, ensure you engineer your paper so the seams on the two papers do not overlap. For painting, you may want to touch up the seam areas of the material with joint compound. For a smoother finish appearance, those with some drywall experience may skim-coat the material for the smoothest possible surface.
Bridging material covers wall surfaces beautifully, but it does have limitations. The biggest limiting factor is the physical construction of a brick or concrete wall. Sometimes these surfaces can be miss-aligned to the point that slight bulges or other irregularities will appear through the surface of the material. The point to keep in mind is that bridging material is a excellent fix for most situations and not a cure-all.