TL-0025 — Spraying Procor® 75 at Low Temperatures Technical Letter

General

PROCOR^® 75 spray grade is a two-component, synthetic rubber, cold-vulcanized, liquid applied waterproofing membrane. It cures to form a resilient, fully-bonded elastomeric sheet. PROCOR^® 75 spray grade can be spray applied to horizontal or vertical surfaces in a single layer of up to 0.125 in. (3 mm) thickness with correctly specified spray equipment. With spraying, application rates of up to 75 gallons/hour (300 liters/hour) are achievable. PROCOR^® 75 spray grade can be sprayed at ambient temperatures as low as 20^°F (-7^°C).

Material Handling

Part A: At temperatures above 20^°F (-7^°C), no additional heating is required to pump and spray Part A. The Part A drums should be thoroughly pre-mixed before spraying.

Part B: PROCOR^® 75 Part B is water-based and it is essential that it is kept above freezing in storage and use. At ambient temperatures of above freezing, some form of low level heating system should be used. The easiest way to achieve this is to store the Part B in heated storage or box truck. If the temperature is likely to drop below freezing, it is important not to leave Part B in the machine or hoses when it is not being used. The Part B should be flushed out with PROCOR^® Flushing Oil to prevent the hose from freezing up.

Heated/Insulated Hoses

The key to successful cold weather application is to minimize pressure drop and cooling as the material is pumped along the hoses. Even if the materials are stored or pre-heated to temperatures above freezing, there can be significant cooling along the length of the hoses, particularly during down-time when the material will quickly cool to ambient temperature. To counteract this, either insulated, or heated and insulated, hoses should be used.

Pre-insulated and heated hose systems are available from the spray equipment manufacturer.  To minimize pressure drop it is critical to use hoses with the recommended diameters 3/8 in. (9.5 mm) for Part A and 5/16 in. (8 mm) or larger for Part B. If extension hoses are needed, they must have a greater diameter than noted above and must be fitted between the spray machine and the lower diameter hose. For example, to achieve a hose length of 150 ft (50 m), use a 3/4 in. (19 mm) diameter extension hose for Part A and 1/2 in. (13 mm) diameter extension hose for Part B.

Substrate Temperature and Condition

Although PROCOR^® 75 spray grade can be sprayed onto substrates as low as 20^°F (-7^°C ), care should be taken to ensure that there is no condensation, ice or frost on the surface of the substrate as this will affect adhesion of the membrane. If ice is detected, steps should be taken to melt the ice. Also, at temperatures below 40^°F (5^°C) a longer cure time will be required to ensure that the PROCOR^® is sufficiently cured to allow protection board installation and backfilling.