Fabric reinforcement is a highly effective method to add strength and bridging ability to liquid applied polymeric coatings. This procedure, when applied correctly, provides a strong, durable repair that is essential to the success of any coating application. The concept of using fiber or fabric reinforcing to increase the strength of a compound is well established; steel in concrete, drywall tape and spackle, fiberglass and polyester, just to name a few.
The success of any application depends on achieving full saturation of the fabric by the coating, eliminating all air within the fabric. A common misperception is that it is sufficient to merely apply enough coating to grab the fabric, then saturate it from above by pouring it on and letting it soak in. The fabric is already saturated with air; coating poured on top of dry fabric will normally trap the air in the fabric and dry above a weak, porous substrate of unsaturated fabric. This will lead to failure of the repair as water permeates the fabric and causes delamination.
A strong composite of fabric and coating is created when all of the air is squeezed out of the fabric. The most reliable way to achieve this is to apply a nice heavy wet film thickness of coating and lay the fabric into it. Light, firm brushing or stippling on the surface of the fabric forces it down into the coating and allows the wet coating to rise up into the fabric, saturating it from below and displacing the air. The fully saturated fabric may then be sealed with another coat to seal the surface, build thickness, and even the texture.
Andek Corporation produces two types of fabric, Roofab and Polafab which, when combined with polymeric coatings, will form strong composites for effective reinforcing and repair. Roofab conforms to uneven substrates and resists fishmouths and tenting. It achieves high strength repairs that remain flexible and spread substrate stress from expansion and contraction evenly across the repair. Polafab is a low profile, light elastic fabric that disappears effectively into the coating to produce a seemingly invisible repair.