ITEM #0707001A – MEMBRANE WATERPROOFING (WOVEN GLASS FABRIC)

Description: Work under this item shall consist of furnishing and applying a waterproof membrane system to the surface of concrete decks and curbs as shown on the plans, in accordance with these specifications, the manufacturer's recommendations, and as directed by the Engineer

Materials: Materials for this work shall be as follows:

Curb primer shall be SEBS bitumen primer, or approved equal.

Deck primer shall be a rapid cure primer conforming to ASTM D41.

Curb bitumen shall be a SEBS modified liquid bitumen and conform to the following tests: Softening Point; ASTM D-2398: Penetration at 77°F; ASTM D-5: Flexibility; CGSB 37-GP-50M: Elongation at 77°F; 700%; Flash Point; ASTM D-92: Flow at 140° F; ASTM D-1191.

Deck bitumen shall be liquid bitumen conforming to ASTM D449, Type III.

Woven glass fabric shall be a fabric saturated with resin or asphalt and conform to ASTM D1168.

Construction Methods: Only concrete surfaces with smooth, rounded projections of a height and depth under ¾” may be waterproofed. Any hole or projection considered detrimental to the performance of the membrane by the Engineer shall be repaired prior to installation of the membrane. The repair method shall be subject to the approval of the Engineer.

No priming or waterproofing shall be done in wet weather or when the temperature is below 35° F, without special authorization from the Engineer. Should the surface become wet it shall be allowed to dry prior to application of the primer.

After the concrete surface is deemed acceptable, the surface shall be thoroughly cleaned of loose or foreign substances by blowing the area clean with compressed air or leaf blowers.

At the curbs, apply the curb primer, a minimum of 2” up the face of the curb and extending 16” onto the deck. The curb primer shall be applied with a roller or spray without allowing the primer to pond. The curb primer shall be applied at a rate of not less than 1 gallon per 100 square feet. Drying time for the curb primer is approximately one hour at 77° F and 55% relative humidity.

On the remainder of the deck, the deck primer shall be applied with a sprayer, roller, or squeegee without allowing the primer to pond. The primer shall be applied at a rate recommended by the Manufacturer, but not less than 1/20th of a gallon per square yard. The primer normally requires 2 hours of drying time at 77° F and 55% relative humidity. Higher temperatures require less drying time.

Both the liquid bitumen and the liquid modified bitumen shall be contained in double jacketed melters or shall be delivered directly to the job site by tanker truck. Liquid bitumen in melters shall be heated to a temperature between 300 and 460° F. The temperature of liquid bitumen in tanker trucks shall not exceed 480° F. Melters and tanker trucks shall be equipped with approved thermometers. Melters shall be equipped with an agitation system to prevent local overheating.

At the curbs, apply a base coat of the hot modified liquid bitumen over the areas on the curb and deck previously coated with the curb primer. Place an 18’ wide strip of woven glass fabric on the base coat, a minimum of 2” up the face of the curb and the remaining width extending onto the deck. Care shall be taken to ensure that the strip of fabric is pressed firmly against the curb. Apply a top coat of hot modified liquid bitumen over the strip of fabric to ensure a watertight joint along the curb line.

Whenever possible, placement of the woven glass fabric on the deck shall begin at the curbs (the low point of the surface) so that water will run over and not against or along the laps. Beginning at the curb line, apply a base coat of hot liquid bitumen for a width slightly greater than the full width of the fabric and roll a full width strip of fabric into the bitumen. Press the fabric into place to eliminate all air bubbles and to bond the fabric to the base coat of bitumen. Each subsequent strip of full width fabric shall be “shingled” into a base coat of hot liquid bitumen so that there will be 2 layers of fabric at all points with longitudinal laps not less than 2” wide. All end laps shall be at least 12”. If so ordered by the Engineer, additional strips of woven glass fabric shall be placed over any other areas of the concrete surface which the Engineer believes require special protection.

After the fabric has been placed on the surface to be waterproofed, apply a top coat of hot liquid bitumen to saturate the entire fabric area. The top coat of hot liquid bitumen shall be sufficiently heavy to completely conceal the fabric weave. Special care shall be taken that all laps are thoroughly sealed down. If areas of fabric are exposed after this application of liquid bitumen, or are determined not to be thoroughly saturated, an additional coat of liquid bitumen shall be applied to those areas.

The Contractor shall also take adequate measures to prevent the liquid bitumen from flowing into deck joints, weepholes or drainage facilities whenever such items are present in the deck.

The entire waterproofing membrane shall be free of wrinkles, air bubbles, or other defects. In the event bubbles or blisters form under the membrane, they shall be punctured with a sharp pointed instrument and the membrane pressed firmly into contact with the deck. All tears, holes, or inadequately lapped seams or other damage shall be repaired with a patch. Patches, made of layers of hot liquid bitumen and fabric, shall extend at least 12” beyond the outermost damaged portion, and the second ply shall extend at least 3” beyond the first.

Vehicular traffic shall not be allowed to pass over the finished membrane waterproofing. The Contractor shall take every precaution necessary to prevent damage to the finished membrane by t workers and equipment passing over it.. Only necessary construction vehicles may travel over the membrane. The Contractor shall repair, at his expense, any damage that occurs to the membrane.

Upon completion of the membrane waterproofing, at least one course of the hot mix asphalt overlay shall be placed as soon as practical in order to prevent damage to the membrane waterproofing. In no case the membrane shall be left unprotected for a time period to exceed the recommendations of the membrane manufacturer.

Method of Measurement: This work will be measured for payment by the actual number of square yards of waterproofed surface in the completed and accepted work.

Basis of Payment: This work will be paid for at the contract unit price per square yard for “Membrane Waterproofing (Woven Glass Fabric)” which price shall include furnishing all materials, equipment, tools, labor and incidentals necessary thereto to complete the work.

ITEM #0707001a