2024-25_NTCA_Reference_Manual_dig_dwnld

Waterproof Membrane Document

NOTE: Not all waterproof membranes meet the requirements of ANSI A118.10. Waterproofing applied by other trades may not comply with ANSI A118.10 and may be difficult or impossible to bond with the setting materials used in the ceramic tile industry. When the waterproofing has been applied by others, determine what material was used and consult the setting material manufacturer to determine compatibility with specific setting materials. TYPICAL USAGE OF ANSI A118.10 WATERPROOF MEMBRANES OCCURS IN THE FOLLOWING AREAS A. Above grade restrooms – residential and commercial B. Parking garages over working or living areas

INSTALLATION A.Use proper bond coat material when required.

1. Some sheet applied waterproof membranes require specific materials to bond them to the substrate. Consult with the membrane manufacturer for specific recommendations. Do not substitute other materials that the membrane manufacturer has not specifically recommended. B. Use reinforcing fabric when required by the manufacturer. 1. Some waterproof membranes require a reinforcing fabric to be embedded in the membrane during application. When required, apply to 100% of the area being covered. 2. Some membranes do not require reinforcing fabric in the field material but they may require special flashing kits to be used where changes of plane occur such as between the wall and floor or around protrusions. These flashing kits usually consist of a liquid and polyester mat or the polyester mat may be set into the waterproofing material in these critical areas. Failure to use the proper flashing material may result in cracking of the waterproof membrane. C. Apply the waterproof membrane to the proper thickness. 1. Manufacturers of liquid applied membranes may require application at different thicknesses depending on the performance requirements of different areas. Examples: Commercial areas versus residential areas. Read the manufacturer’s printed instructions for thickness requirements. 2. Some membranes may lose up to 1/2 their volume going from a liquid state to dry. This should be considered during application when trying to establish proper thickness per manufacturer’s instructions. TESTING FINISHED WORK A. Waterproof membranes should be inspected as soon as possible after application to discover any pinholes or voids in the membrane. Application of more material to correct defects or replacement of some material may be required. B. Water testing a waterproofing application should be conducted prior to application of any tile as it is very difficult to correct deficiencies once tile has been installed. Consult the manufacturer’s instructions for the minimum curing time prior to water testing.

C. Balconies D. Roof decks

E. Steam showers F. Gang showers G. Normal showers – residential and commercial H. Fountains

I. Above grade swimming pools J. Above grade kitchen areas

SUBSTRATE PREPARATION A. Consult the membrane manufacturer for the maximum allowable moisture flow emanating from the substrate prior to application. 1. Test the moisture flow with the calcium chloride test to determine the moisture flow per 1,000 square feet in 24 hours. 2. If moisture flow is within allowable tolerances, apply membrane. 3. If moisture flow is in excess of allowable tolerances, consult the membrane manufacturer for recommendations to reduce moisture flow to acceptable levels. 4. Check with the membrane manufacturer for product limitations regulating pH levels and alkalinity. B. Substrate should be prepared according to the membrane manufacturer's recommendations. 1. Some membranes will crack if applied to substrates with irregularities such as gouges, holes or voids in the surface. 2. Apply underlayment material to rid the substrate of irregularities. C.Membrane should be installed over proper slope. 1. If the proper slope to drains is not already established in the substrate, it should be established prior to the application of the membrane. Failure to slope the membrane results in moisture or water collecting in the mud bed or setting material, which can result in problems with mold, mildew, tile and grout discoloration, etc.

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NTCA Reference Manual | 2024 / 2025

Chapter 4 | Membranes