Permanently adhering nearly anything to a porous substrate can be a nightmare at times. The problem is that, because the substrate is porous, it will absorb the adhesive and shorten the usable life of the carpet, linoleum, or other material that should remain glued down for a long time. The solution to this problem, and problems like it, is the use of an adhesive primer. This type of primer is a liquid product, typically made with latex, that is "painted" onto a substrate and allowed to dry. These primers are used to increase the bonding quality of any adhesive, whether it is pre-applied, as with peel-and-stick tile, or if it must be spread, as with indoor/outdoor carpeting.
Latex adhesive primer is usually water-based, and it dries relatively quickly. Depending on the ambient air temperature and the relative humidity, dry times range between 30 minutes and three hours. Substrates can be either vertical or horizontal, and include drywall, wood, plaster, masonry, concrete, wood and wood underlayments, and poured-in-place gypsum subfloors.
The area that will be primed with adhesive primer should be ready to go before the primer is applied to the substrate. This means that the area to be primed, the primer, and the adhesive should be kept at or above 65°F (18.3°C) for at least 48 hours before and 48 hours after the primer and adhesive are installed. This will ensure that the primer dries evenly, and that the adhesive itself will dry correctly. Warm materials bond to adhesive more readily than do cold materials. That is why the surface must be acclimated as well.
Before adhesive primer is applied, the user should be sure the substrate is clean. This means that it is free of any kind of surface contaminants that will prevent the primer from working at its ideal level. Any dust, dirt, wax, polish, paint, oil, grease, or other contaminants that will interfere with effective material bonding should be removed. The substrate must also be in good, usable condition, and be relatively smooth and dry.
The amount of coverage that will be provided with a given amount of adhesive primer will vary depending on the porosity and the smoothness of the substrate. Rougher substrates should be smoothed as much as possible with a patching and leveling compound. The compound should be dried and cured according to the manufacturer’s recommendations before adhesive primer is applied.
When applying adhesive primer, a short nap paint roller or a coarse fiber brush should be used. If puddles form during application, they should be rolled or brushed through so they will not become a bonding issue when the adhesive is applied. This primer should be used at full strength, and tools can be cleaned with warm water.