Epoxy wall coatings: Epoxy coatings have been around for a long time and were initially solvent loaded materials. The increased awareness of environmental safety has forced the coatings industry to develop VOC standards, resulting in reformulation of compliant epoxy resins. For epoxy wall coatings to be compliant they must contain less than 18% volatile organic content by volume which is still a significant vapor load on large jobs. That is the equivalent of 18 gallons of solvent introduced to the job site air for every 100 gallons of coating used. More progressive technologies have produced 100% solids resins with very low VOC emissions, some materials are LEED compliant. Thickness should be 10 to 12 mils DFT.
The advantages of 100% solids epoxies over solvent or water based formulations are: a) a safer work place b) higher build on the walls (can achieve a DFT of 10-12 mils or more) c) improved molecular cross linking for increased hardness and chemical resistance d) higher gloss and gloss retention; all of which result in improved life cycles and durability. The primary disadvantage is a shorter working time which results in higher cost. Water based technology simply does not perform at the same level for a number of reasons.
Urethane Coatings: 100% solids urethane coatings are a newer technology that has come in favor in the last decade. All application principle are comparable to epoxy coatings but the urethane resins out perform epoxies in every aspect. The primary advantages of urethane are increased hardness which gives higher gloss and gloss retention than epoxy, increased chemical resistance to sanitizing solutions, improved abrasion resistance and increased life cycles. The primary disadvantage of urethane coatings is that the working times are very short and require more labor and materials to install and the resin cost is roughly twice that of 100% epoxy materials. Thickness should be 10 to 12 mils DFT.
NOTE: Standard systems(Epoxy and Urethane) without Coating upgrades are labeled as non-reinforced (NR)
Coating Upgrades:
Upgrades for epoxy and urethane coatings occur with drywall or other hollow wall construction substrates as well as CMU: Durability and finish appearance are the driving forces. |
Fiberglass Reinforced Coatings (drywall): For good installations the substrate needs to be smooth and paint ready to assure there are no air voids within the fiberglass mat. In this system a 5.6 oz. woven fiberglass mat is layered on the face of drywall in a wet lay up method. After it is cured it is sanded to remove imperfections and then the epoxy system is applied; one coat of primer followed by two coats of 100% solids coating. The coating can be either epoxy or urethane. The performance advantages of each of the coatings are still as listed above. The main advantage of the fiberglass system is the increase in structural integrity of the drywall and the increased performance from the thicker overall coating. The total system thickness will be about 30 – 35 mils. |
Paging the substrate: There is a move to replace drywall with more durable “board” products in an attempt to reduce water sensitivity and to increase impact resistance. Some of these products do not have smooth surfaces and therefore when finished do not present a finish that is either aesthetically acceptable or easily cleaned. Consequently they have begun to parge the surface with an overlayment to create a smoother finish. We have had a high level of success using a Portland based latex mixture filled with fiberglass strands. This product is BOCA code approved for dry stacked CMU walls which speaks to it’s strength, durability and it can be made smooth. It does require a skim coat of block filler to fill surface porosity followed by the usual primer and two coat finish; either epoxy or urethane. Parging is also used to provide a smooth finish on CMU walls in conjunction with the standard finish protocol. The parging process is time consuming and needs cure time between the latex parge and the final coating process. The finish characteristics and performance quality is still the equivalent of the coatings referenced above. |
Troweled Quartz (TQ): Troweled quartz walls are another for of parging and are simply the extension of the flooring cove base up the wall to the desired height; generally either 4 feet or all the way to the ceiling; we have installed TQ as high as 14 feet. TQ increases aesthetics, improves performance for high pressure washing and impact, increase chemical resistance and extends life cycle performance. In the one application you can achieve a smooth surface in CMU or rough hard board surfaces and incorporate the final finish coat in one system. The process requires more install time than coating systems but is faster that the parging process. There is no intermediate curing period required during the process. |
Considerations:
Cost: Both the epoxy and urethane systems are applied with the same protocols; a) a primer and two coats for dry wall b) a minimum of 2 coats of block filler to eliminate pin holes on block followed by a primer and two coats once the pin holes are eliminated.
Applications: Conventional Vivarium with dry housing; coatings have not functioned well in free ranging primate areas, dog areas or pressure wash cubicles, chemical resistance can be poor with epoxy. Dog and large animal housing, spray down cubicles, wet areas and especially good in free housed primate areas.Troweled Quartz (TQ) is excellent for dog and large animal housing, spray down cubicles, wet areas and performs particularly well in free housed primate areas. |
