Can You Use Luan for a Subfloor Under Tile?

About Lauan

• Luan is harvested from tropical hardwood trees in places like the Philippines, Indonesia, Thailand and Malaysia. Trees are cut down and then spun on a rotary while blades peel thin sheets from their trunks. Luan is used for set design in the theater industry, for interior doors, for truck paneling and as backing in furniture.

Problems With Lauan

• Tropical hardwood plywoods contain oils that make them unsuitable for use as a tile subfloor. The oils react with water and cause what is called "delamination," or adhesive failure. According to one installer, even the moisture in thin-set can cause delimitation when applied to luan. When the adhesive fails, tiles don't completely adhere to the subfloor, which can cause buckling, cracking or can cause tiles to pop off the floor completely. In addition to problems with delamination, plywood expands and contracts with changes in moisture levels, this can also lead to cracked tiles.

Alternatives to Luan

• Concrete backer board is the most commonly used alternative to plywood. It doesn't expand and contract with changing moisture levels, is durable and won't cause delamination. Homasote is a backer board made from compressed 100-percent, post-consumer recycled newspaper and is ideal for use as a subfloor. It is water-resistant and rated for use both indoors and out.

Installation Tips

• While tile can be laid over a number of existing floor types, it is best to remove the old floor and inspect for wet spots or any other damage to the subfloor. When using backer board over plywood, use thin-set to adhere the backer board to the plywood and then secure it with underlayment screws. These screws sink into the backer board so they won't interfere with your tile surface.