A bond breaker material should be used when constructing a joint to prevent three point adhesion. Joints should be designed and located so that the limit of movement in any direction does not exceed 25% of its width. Manufacturers of sealant joint material have expertise to offer when either designing new or replacing old sealant joints. I strongly recommended that you consult sealant manufacturers when designing and constructing sealant joints.

Promenade and terrace deck waterproofing systems are designed and installed very similar to roof systems. The major difference is waterproofing systems must be able to support foot or vehicular traffic. The two most common type of membranes used for promenade or deck waterproofing are liquid applied or loose laid sheet membrane.

The advantages of a liquid applied system are:
• Material is spread over the entire deck as a liquid and dries to form a monolithic surface- no seams.
• The finished surface can come in direct contact with pedestrian or vehicular traffic.
• Membrane is fully adhered to substrate resulting in minimal water migration between deck and membrane making leaks easy to find.
• Easy to maintain since membrane is expose.

The disadvantages to liquid applied membranes are:
• Expensive and time consuming deck preparation in retrofit applications. Deck must be clean with no contaminants for membrane to properly bond.
• Substrate cracking is detrimental to the system as it can reflect through the membrane.

Sheet membrane advantages are:
• Preparation of the substrate is not as critical since membrane is usually separated from deck by a separation course.
• Deck contamination and deck cracking is not as crucial.

Sheet membrane disadvantages are:
• Cannot directly support pedestrian of vehicular traffic - must use protection course.
• Maintenance and repairs are costly. Protection course must be removed to expose membrane.
• Leaks are difficult to find since water can travel between loose laid membrane and substrate.

In summary water can have devastating effects on a structure. Keeping water out of a building begins in the design stage. Good design must be complimented by quality workmanship and the use of the right construction materials for the given application. The rest is up to the facility manager. The manager must have a good maintenance system in place which incorporates routine inspections. The water tight integrity of the building envelope will only be as strong as the weakest link in the construction and maintenance chain. Facility managers play a critical role in keeping water out of a facility. They are the maintenance link in the chain to a watertight structure.

Back