Joe Grady's September 2004 column (Do It by the Book: Use the Right Backerboard for the Tile Application) incorrectly identifies the manufacturer for DensShield. DensShield [is] manufactured exclusively by Georgia-Pacific.

Also, DensShield conforms to more details in the TCA Handbook than detail F151-03, which was cited in the article for use with 8-inch-square or larger tiles. In fact, the more common floor detail is F146-03, which requires a minimum tile size of 2-by-2 inches over 5/8-inch plywood with joists spaced 16 inches o.c.

Lastly, G-P Gypsum has conducted tests at TCA where DensShield has achieved a light commercial rating over 3/4-inch OSB or plywood and joists spaced at 19.2 inches o.c. - the typical spacing for engineered lumber joists.

Kieren Corcoran

National Sales Manager for G-P Gypsum

- Residential Products

You are absolutely correct, Kieren. The misidentification of DensShield's manufacturer occurred as the result of an editing error. In addition, the article stated that Custom Building Products' EasyBoard is suitable for use over subfloors. In fact, the product is designed for use over vertical surfaces only. Also, the article indicated that backerboard deflection can cause tile and/or grout cracking. Actually, deflection of the entire substrate system - not necessarily the backerboard itself - would be the culprit in this instance. We regret the inaccuracies. - Editor