By Phil Reinhard, NGPP Public Relations Chair

into choosing the appropriate primer for the most commonly found, and a

few less common surfaces to be covered with wallcoverings. It is important

to understand a few things before progressing with this discussion. First, the

reader needs to understand that this article is meant as a guideline only. The

information contained in this article should be used to help make decisions on

wall preparation that will save the paperhanger time, increase the ease of

installation, help jobs last, and facilitate future removal of the wallcovering.

There are other products that will work in many cases, and there is always

more than one path to a successful job. Also, the information contained in this

article is not necessarily the opinion of the National Guild of Professional

Paperhangers; it is based on the training, experience and research of the

author.

Wall preparation is one of the least emphasized aspects of paperhanging, yet

more jobs fail due to prep than any other single factor. (To see more on the

importance of wall preparation and priming see the last issue of Jobsite.) In

this article we will investigate the various types of primers and their uses in

paperhanging. Hopefully, this article will serve as a guide when choosing

primers for your paperhanging projects.

It is also important to understand that primer and sizing are two different things.

In paperhanging, a primer is a coating similar to paint, applied to a surface to

either seal it or improve the surface’s ability to accept the bond of the wallcovering

and also to release that bond at removal time. Sizing is a thinned adhesive

applied to the surface strictly to improve the bond. On some occasions,

both primer and sizing may be needed.

There are four main categories of primers for wallcovering installation, oil base,

pigmented acrylic, clear acrylic, and a relatively new category, drywall repair

primers. We’ll look at each category, one at a time, and discuss the strengths

and weaknesses of each.

The oldest type is oil based primer. Oils have been used as wallcovering

primers for years, since they do a great job of sealing a surface like new drywall

one coat. Recent changes in VOC (volatile organic compounds) regulations

have forced the paint industry to change these primers. This has not changed

their ability to grip to a surface, or to seal it. What has changed, however, is the

ability of the oil based primer to accept the bond of the wallcovering adhesive.

Adhesive manufacturers now recommend that any surface primed with an oil

base primer needs to be coated again with an acrylic primer. This additional

step, along with the odor and clean-up process associated with oils, has made

many users change over to acrylic primers. Oils are still a valid choice as a

wallcovering primer in many instances. New drywall needs to be thoroughly

sealed before wallcoverings are installed, and oils perform this function well.

Walls that have extensive patching, or skim-coating are also candidates for oil

priming. Basically speaking, a very porous surface or new drywall are the two

main areas where oil based primers should be considered. Just remember, it

is important to coat the oil primer with and acrylic primer to ensure the bond of

the wallcovering.

Next on our list is pigmented acrylic primer. These primers are solid color, usually

white (although there are now some gray primers in this category) and have

a paint-like consistency. They are designed to use in most situations where oil

primers are used, such as a new drywall surface. The main advantage of this

type of primer is that the wallcovering will adhere to it with no additional coat

of prep, making it a one coat system. Pigmented acrylics will leave an even

color background for the wallcovering, important in many cases to avoid shading

of the wallcovering due to uneven coloring of the wall showing through.

This brings up a second instance where pigmented acrylics are useful, a dark

painted room, or a room where patching creates contrast to the painted surface.

As with any primer, it is important to apply a full, wet coat of pigmented acrylic

primer for it to perform well. It should be cut in just like a paint job. Then it

must be allowed to cure fully before application of the wallcovering. Failure to

allow cure time may lead to the primer loosening when the moisture of wallcovering

adhesive is applied to the surface. While most pigmented acrylic

primers’ instruction say a two to four hour dry time is sufficient, a three to four

day cure time has proven to greatly enhance the ability of these primers to

stand up to the moisture of wallcovering application. This cure time is critical

in situations where wallcoverings will be re-positioned frequently and also

where double cutting of seams will be done, such as in a commercial application.

Pigmented acrylics are an excellent choice in many situations, but proper application

and cure time are very important to ensure a successful job.

The next category of primer is clear acrylics. These are the basic wall-prep

products most prolific in the business. They are easy to apply, do a good job of

enhancing a sound surface, and facilitate easier removals down the road. The

best use for these products is on a well painted surface. For example, a wall

painted with one coat of builders’ grade flat latex is not considered a well painted

surface, and a basic clear acrylic will not give you much protection from

future failure of the painted surface. But a wall that has been well painted with

quality paint is a great candidate for a clear acrylic primer. These primers

adhere well to a sound surface, including those with a sheen, but as with any

coating, applying a clear acrylic to semi-gloss or glossy surface should be preceded

by sanding and dusting to promote proper adhesion.

Clear acrylic primers are the most commonly used primers in the wallcovering

industry, and do the job very well, as long as the primer is applied properly.

A sub-category of clear acrylics is a line of primers known as “tack preps.”

These are primers that dry with a sticky feel to them. These are especially useful

in situations where wallcoverings are being applied to hard, slick, or highly

sealed surfaces. For example, gloss paint can be made ready for wallcovering

by lightly sanding, dusting, and applying a full coat of tack prep. As with any

primer it is important to apply it properly and cut it in. Other surfaces, such

as glass and laminates have been successfully wallpapered using tack preps.

It is important that these surfaces be cleaned thoroughly before priming, to

ensure a bond of the primer.

Until a few years ago, the three types of primers describe so far were all that

were available to the paperhanger. But that left a couple of situations where

there was no primer available to thoroughly prepare an area for wallcovering.

Builder’s grade flat latex paint has long been the nemesis of paperhanging. It

is an extremely porous finish, low in binding agents and full of extenders. Add

to that the fact that it is usually sprayed onto new sheetrock that has not been

dusted and the bond is further weakened. The moisture and surface tension of

wallcovering installation has caused many jobs painted with builder’s flat, by

the paint releasing from the wall. Obviously, if the paint falls off, anything

applied on top of it will come with it. Most standard primers soak into the paint

to a certain degree, but do not get through it and improve the bond. Even oil

based primers, which penetrate better than most other primers, cannot re-bond

these paints to a wall.

Builder’s grade flats have also caused many a headache for wallpaper

removers, especially if the wallpaper is hung directly on the paint or if a thin

coat of clear acrylic primer was used; the removal solution would penetrate the

paint and the sheetrock paper. The surface of the wall would be torn up by

scraping the old wallpaper off, leaving a very tough surface to spackle and prep.

Removal of paper from un-primed drywall has also led to severely damaged

walls, even when pulling a strippable paper from the surface. The paper face

of the drywall is frequently destroyed in these cases.

Several years ago a primer was found to solve both of these problems. Now

know as drywall repair primers, they penetrate the surface and lock down the

loose drywall paper or the poorly bonded builder’s grade paint. For damaged

drywall (the original use for this primer) a coat of this thin, clear, high resin

primer has the ability to penetrate the loose drywall paper torn apart during

wallpaper removal and create a solid surface, making it easier to skim coat with

joint cement without creating bubbles. Previously the surface needed to be

primed with an oil primer, let dry overnight, and then skimmed, and then have

any bubbles cut out and re-spackled, creating a multi step job to get back to a

sound surface. With the drywall repair primer, the process is shortened due to

the rapid drying time, and the elimination of bubbling drywall paper.

The drywall repair primer also has been found to be an excellent primer for the

skimmed wall. The primer penetrates and solidifies the drywall compound used

for skim coating, even adhering well to “hot muds,” those powdered drywall compounds

that dry very quickly, but don’t hold a finish as well as regular compounds.

Drywall repair primers were also found to do an incredible job of priming builder’s

grade flat paints, by penetrating through the paints and locking them down to the

drywall. The problem of the paint failing and taking the wallpaper with it is virtually

eliminated when using drywall repair primers as a wallcovering primer. Using

these primers has been a great step toward eliminating the problem of hanging

wallcoverings over builder’s flat paint. Drywall repair primers also make wallpaper

removal from builder’s flat paint easier, by creating a much harder surface and

eliminating the problem of re-wetting the paint during removal.

There are a couple of problems associated with these primers, however. The

primers are generally very thin, (almost water like in viscosity) which makes

them difficult to apply cleanly. It takes care to keep the primer on the wall and

in the roller and brush rather than dripping onto floors, trim and other surfaces

not being primed. Use of a high quality roller cover helps tremendously. It is

also important to apply a very wet coat of these primers for them to work to their

full advantage.

These primers dry very hard, and have a slight sheen, which is not always the

best type of surface to install wallcovering on. Many installers prefer to re-coat

the drywall repair primer with a clear acrylic primer to ensure a good bond,

while others will size the wall with a thinned adhesive. Either step is good, and

one or the other should be used in order to fully ensure proper adhesion of the

new wallcovering.

Hopefully this guide to wallcovering primers will help you in choosing the best

primer for your next wallpaper installation. Remember that this is a guide, and

the conditions of every job vary, so the final decision is always yours. The most

important part in ensuring the success of a wallpaper job is wall preparation,

and the proper application of the right primer is critical to the performance of

job, helping to make for a wallpaper installation that does the three things the

customer wants; a job that looks good and installs well, a job that lasts as long

as the customer wants, and a job that can be removed easily when time for

redecorating comes along.

In the next issue we will list the major manufacturers and suppliers of wallpaper

primers and the brands of primers in each category.