Fastening plywood to the floor screed - choose the right composition
Good afternoon.
Due to the lack of information on the laid communications (electricity, heating) in the floor screed, I plan to lay 12 mm plywood under a massive board without using self-tapping screws. Tell me, what glue is better to use when laying plywood in this way?
Maxim
Expert Answer
Hello Maxim!
The fastening of plywood to the floor screed is widely used today. A similar fixation method is used both because of the presence in the base of the floor of engineering communications and the contours of the water floor, and because of the many advantages that the use of adhesive composition gives:
- high strength and reliability of the connection;
- ease of installation;
- good waterproofing properties of the adhesive layer;
- resistance to temporary changes;
- possibility of use for underfloor heating.
Today on sale you can find a variety of building adhesives that can be used for gluing plywood with a floor screed. Among them, three main groups can be distinguished:
- water based adhesives;
- single component formulations;
- multicomponent adhesive mixtures.
The advantage of water-based materials is their environmental friendliness and the complete absence of unpleasant odors. Glues of brands Stauf M2A-700, WAKOL D1640, Uzin MK-61, etc. are ideally suited for residential premises with installed floor heating system. They provide a solid connection of multilayer lumber, which is just what plywood and OSB are. The only drawback is the relatively long drying period. As for the installation features, after applying the composition and joining the glued surfaces, plywood will need to be loaded with something heavy - furniture, building blocks, etc. The consumption of water-based glue is up to 1.2 kg / sq. m
The basis of one-component adhesives are alcohol solutions or inorganic solvents. Due to their high evaporative ability, the plywood coating can be operated on the third day after installation. The use of one-component adhesive simplifies good fluidity. In addition, its advantages include the fact that after drying, the joint surface remains elastic and does not lose strength after long-term operation. Adhesives made on the basis of artificial materials of Ibola L-12, Stauf WFR, Tarbikol Bostik or Aned A-1 adhesives emit a strong odor when applied, so work with them in a respirator. Consumption of one-component adhesive is up to 1.5 kg / sq.m.
As for multicomponent compositions, they give the most durable connection, but at the same time they are the most expensive and difficult to use. Glues of the Ibola R-200, ACM or Parcol PU2K brands with polyurethane-epoxy resins in the composition do not contain moisture and are excellently suitable for application to materials subject to warpage. Drying of such a composition lasts less than 24 hours.
And the last thing I would like to say on the essence of your question. Before starting installation work, it is necessary to thoroughly clean the concrete base from dust and soak it with deep penetration soil. Standard sheets of plywood are cut into four parts to obtain panels measuring 75x75 cm. Their lower surface is treated with a liquid primer from a phenol-formaldehyde adhesive mixture and a solvent. After that proceed to the application of glue. Its layer should not be thicker than 2 mm, so it is convenient to use the appropriate notched trowel to remove excess material.Sheets are laid on a screed and pressed with a load. The laying of the top coating is started after the glue has completely dried. If necessary, the joints of individual panels are treated with a grinder.
