517Waterproofing

Waterproofing

Description

517.01This work consists of waterproofing concrete surfaces per these specifications and in

conformity with the plans or as directed.

Materials

517.02Materials for waterproofing shall conform to the following:

ASTM Item Use Designation Asphalt Primer D41 Primer under asphalt mop coats *Asphalt Mop Mop coats with or without D449 Coat membrane Woven Cotton D173 With asphalt membrane Fabric * Type I is for use below ground and shall be heated to a temperature of between 225 and 275 °F. Type II is for use above ground and shall be heated to a temperature of between 275 and 325 °F. Type II shall be used unless otherwise specified.

For hot application, materials for waterproofing shall be heated to a temperature of between 175 and 225 °F in a heating kettle or tank constructed as a double boiler, with a space between the inner and outer shells filled with oil, asphalt, or other material for heat transfer and for positive temperature control. Heating kettles shall be equipped with thermometers and the material shall be stirred continuously to avoid overheating.

Construction Requirements

517.03All concrete surfaces to be waterproofed shall be free of loose material and dirt and

shall be reasonably smooth and free of projections or holes. Waterproofing shall not be started without approval in wet weather or when the temperature is below 35 °F. The waterproofing shall in all cases be started at the low point of the surface to be treated so that water will run over and not against or along the laps.

Beginning at the low point of the properly prepared surface to be waterproofed, a priming coat shall be brushed or sprayed on the surface to penetrate and prepare it for the first mop coat of hot asphalt coating.

After the primer has cured, a section about 20 inches wide and the full length of the surface shall be mopped with the hot asphalt. The first strip of half-width fabric shall be rolled into the mop coat immediately after it is placed. The first strip and all following strips shall be rolled into place to eliminate air bubbles and obtain close conformity with the surface being treated. The first strip and an adjacent section of the surface of a width equal to slightly more than half

517.04 the width of fabric being used, shall then be mopped with hot asphalt and a second strip shall then be rolled into it. The second strip shall completely cover the first strip. The second strip and an adjacent surface of concrete shall then be mopped with hot asphalt and a third strip of fabric “shingled” on. The third strip shall lap the first strip by at least 2 inches. This process shall be continued until the entire surface to be treated is covered and each strip of fabric shall lap at least 2 inches over the next to last strip. The entire surface shall then be given a final mopping of hot asphalt.

The completed waterproofing shall consist of a firmly bonded membrane composed of two layers of fabric and three moppings of asphalt, together with the required prime coat. Each layer must be separated from the concrete surface or other layers of fabric by an intervening mop coat.

The mopping on the concrete shall cover the surface so that no gray spots appear, and on the fabric, it shall be sufficiently heavy to completely conceal the weave. At least 12 gallons of asphalt shall be used for each 100 square feet of horizontal surface and at least 15 gallons for each 100 square feet of vertical surface for each mop coat. The work shall be so regulated that, at the close of a day’s work, all fabric that has been laid shall have received the final mopping of asphalt and the edges of all laps shall be thoroughly sealed down.

Suitable provisions shall be made to prevent water from getting between the waterproofing and waterproofed surface at the edges of the membrane and at any point where it is punctured by such appurtenances as drains or pipes.

Method of Measurement

517.04The accepted quantities of waterproofing will be measured by the square yard based

on the surface area waterproofed.

Basis of Payment

517.05The accepted quantities of waterproofing will be paid for at the contract unit price

per square yard. Payment will be made under:

Pay Item Pay Unit Waterproofing (Asphalt) Square Yard

518.01