Spring 1996
Common Problems:
- Tile installed over water-resistant gypsum board (green
board) instead of a mortar setting bed or cementitious
backer board.
-
Note: The Ceramic Tile Institute has questioned
using green board as a tile substrate in wet areas such
as tub/shower enclosures.
-
Edge of green board above tub or shower
pan lip is cut edge instead of the wrapped factor edge.
-
Joints and penetrations are not sealed
with a coat of ceramic tile mastic prior to tile installation.
-
Insufficient gap (less than 1/4 inch)
between the base of green board and the tub or shower
pan.
-
Lack of flexible sealant joint at the
tile-to-tub or shower pan juncture.
Potential Damage:
- Water intrusion resulting in:
- Tiles popping off,
- Tile and grout cracking,
- Dryrot, structural damage, and framing movement.
Recommended Solutions:
- Install tile over a mortar bed or cementitious backer
board such as "Durock", "Wonderboard",
or equal, per manufacturer's installation instructions.
- Provide proper, flexible sealant joints at all fixture
penetrations and tie-to-tub and shower pan junctures.
Information provided by Building Analysts, a full-service architectural and engineering firm with many years of experience in construction litigation. Their services include: architectural and structural investigations, repair recommendations, preparation of exhibits and expert testimony. Contact Building Analysts at (619) 234-8153.
