Halex has now three products that meet the new Tile Council of North America specification for exterior glue laminated wood panel underlayment as listed on page 34 of their new handbook. All three of Halex's seven ply birch underlayments meet the specifications. The Halex, Multiply and Accuply brands meet TCA specifications. The advantage these products offer is they are much stronger than cementitious panels, lighter to carry, and easier to install because they require no thin set. They can also be stapled which is easier than screws or nails.