Emergency Leak Repair Techniques

Bruce Cunningham, Senior Consultant

Often times after severe weather, building owners are forced to make emergency roof repairs. This article focuses of simple but effective leak repair techniques. Repair procedures should be as simple as possible so they may be performed safely by maintenance personnel or nonroofing professionals. However, these repairs should be considered temporary. Permanent repairs should be make by a professional roofing contractor as soon as weather permits. If the roof membrane is under a manufacturer's warranty, the roofing membrane manufacturer should be contracted in writing.

Leak Repair Procedures

There are too many different types of roofing membranes to tailor emergency repair procedures for each. Consult the roofing membrane manufacturer's literature for products and procedures recommended for emergency repairs. If literature cannot be located or if procedures are not detailed for emergency repairs, the following guidelines are suggested:

• Protect the interior: Control the spread of water in the interior by collecting water in containers or by using plastic sheeting to protect the building contents.
• Remove excess water from the roof: Check roof drains and scuppers to be certain they are open and functional. A frequent cause of roof leakage and roof collapse is excessive ponding on the roof surface is due to clogged grains and/or scuppers.
• Locate the source of the leak: In attempting to determine the source of a leak, locate the point on the roof surface above the area of leakage in the building interior. From this point, first check the condition of rooftop mechanical equipment, then check all flashings at terminations and penetrations. Second, if the system is ballasted with gravel or pavers, remove the ballast from the immediate leak area, then check the membrane surface for cuts or punctures. Finally check the seams in the roof membrane.
• Perform emergency repairs: Once the source of a leak is located, the materials and procedures that will cause the least amount of damage to the roofing membrane should be chosen. Following are some of the best methods foe emergency repair:

Plastic (Roofing) Cement

An emergency patch can be made using plastic cement and fabric or roofing felt. Plastic cement is available in "rain patch" or "wet patch" grades, which are somewhat easier to apply to wet or damp surfaces. Avoid the use of a liquid or pourable asphalt repair product. Plastic cement may deteriorate most types of single-ply membranes, so exercise caution when using.

Sealant and Roof Tapes

To make emergency repairs on some single-ply membranes, start by cleaning the membrane surface with alcohol or a household cleaning solution, such as window cleaner.

After the membrane has been cleaned, apply butyl or polyurethane sealant (caulking), or roof tape to the damaged membrane. The membrane surface must be clean foe the repair material to adhere to it. When using roof tape, pressure should be applied over the entire surface of the tape to ensure adhesion.

Sealants and various roof tape products are available through membrane manufacturers, roofing material distributors, and roofing contractors.

Duct Tape

Duct tape can be used to make a patch on the roofing membrane. The sheet must be clean and dry in order for the tape to stick. This is an easy, but short term repair, unsuitable for ponded areas.

Wood Block

If there is a puncture in the membrane or a small seam problem where the membrane is not totally adhered, make a small circular incision at the puncture or seam. This incision should be large enough to allow a 2" x 4" x 4" wood block through the hole under the membrane.

Place two wood blocks, ont on top of the other, through the hole. Then staple or nail the edge of the membrane to the wood blocking to prevent the hole from enlarging due to stress placed on the membrane. This procedure will raise the hole several inches above the roof surface, out of any ponding or surface water, and should immediately stop the leak. Place a small metal cap, cone or bucket over the hold through which the wood blocks were inserted and secure the cover to stop additional water entry. When a permanent repair is made, the wood blocks should be removed.

Bentonite Clay

Spread bentonite clay granules approximately 1" thick in the area of the leak. The bentonite clay will expand, forming a water impermeable seal which bonds to the membrane surface. Bentonite clay generally necessitates extensive clean-up of the membrane surface prior to permanent repair.

Completing emergency repairs can stop water entry not only into the building, but into the roof system. Less water entry means less wet insulation and less damage to surrounding roof components.