GacoFlex LM-60

Membrane Repair Manual

GacoFlex LM-60, a liquid-applied elastomer membrane, is a two-component, 100% solids, chemically curing urethane rubber. A long-term waterproofing installation depends on practicing proper application procedures as well as protecting finished membrane from physical damage. Gaco Western recommends a visual inspection to identify inadequate film thickness, blisters, pinholes or other physical damage. This visual inspection should confirm adequate membrane thickness and flashing details. When practical, a 48-hour water test should follow visual inspection. Upon satisfactory completion of inspection and testing, the LM-60 membranes must be covered.

Blisters in LM-60 can occur in two forms, random blisters or numerous small blisters. Random large blisters result from contaminated substrate or inadequately mixing LM-60's two components. Multiple small blisters may result from poorly sealed substrates, and/or applying LM-60 in hot sun. Blisters may be repaired in the following manner.

BLISTERS

Cut out and remove delaminated LM-60 coating. Check for and remove any uncured LM-60 that remains on the substrate using a scraper. Solvent wipe substrate and surrounding area to clean the existing LM-60 coating with GacoFlex T-5111 or T-5112 thinners.

Prime entire area with a thin coat of U-5677 primer, carrying the primer a minimum of three inches (8 cm) onto the clean existing LM-60 membrane edge. Allow the U-5677 to dry a minimum of 2 hours, but not longer than 24 hours. Reapply LM-60 at the specified thickness and allow to cure a minimum of 48 hours before water testing and/or covering.

NOTE

For potable water containment, clean surface with a mild liquid detergent and rinse with clean water. When thoroughly dry, prime with E-5320 instead of U-5677.

PINHOLES

Thoroughly clean the surface of the LM-60 membrane. The use of water and liquid detergent followed by a liberal clean water rinse is a permissible method of cleaning. Allow to dry thoroughly. Alternatively, a damp solvent wipe with GacoFlex T-5111 or T- 5112 thinner can be used to clean the LM-60 surface.

Apply by roller a thin coat of U-5677 primer at rate of one gallon per 300 to 400 square feet (4.2L/30-40 m2). Use scrubbing action to work primer into surface. Roll out puddles or thick areas of U-5677 and allow primer to dry--minimum of 2 hours, but not longer than 24 hours--before recoating with LM-60.

Mix sufficient LM-60 Part A Polyol with LM-60 Part B Iso for 1 gallon per 100 square feet (4.1L/10m2) coverage. Thin LM-60 at the rate of 10-15% by volume with GacoFlex T-5112 thinner. Apply LM-60 with short nap roller, using a scrubbing action to roll or work the thinned LM-60 into pinholes.

If pinholes originated from porous concrete, apply of thinned LM-60 in the afternoon after daily maximum ambient temperature. Allow thinned LM-60 coat to dry and cure a minimum of 48 hours before water testing and/or covering.

Normally LM-60 should be recoated between 24 and 48 hours after application in order to achieve good intercoat adhesion. If recoating is not done within specified time interval, Gaco Western cannot guarantee proper intercoat adhesion.

NOTE

For potable water containment, clean surface with a mild liquid detergent and rinse with clean water. When thoroughly dry, prime with E-5320 instead of U-5677.