W. R. MEADOWS has developed a low temperature version of PRECON that must be used when temperatures are below 40°F (5°C). PRECON LOW TEMP can be applied at temperatures down to 25°F (-4°C) and this temperature must be maintained for a period of 24 hours prior and post application. If site conditions are marginal and conditions less than optimal, consider the use of PRECON LOW TEMP below 60°F (16°C).
PRECON and any accessory products must be stored in their original, unopened packaging at temperatures above 40°F (5°C). If the product is to be stored on site, then it is required to be stored in containers that will be able to maintain these temperatures.
Installation of PRECON should not occur in the presence of rain, snow or ice, or if there is any ponded water as a result of melting. The presence of water on the membrane during its installation will prevent the proper adhesion of the joints. Certain environmental conditions may cause the formation of dew on the plasmatic core, which could impede the bond at the selvage edge. This may occur at temperatures above or below 40°F (5°C) and will necessitate the use of MEL-PRIME on the selvage edge to insure a good bond at the seams.
Concrete placement should be completed within 60 days of the installation of the PRECON and it is recommended it be done as soon as possible to prevent damage to the membrane. After installation, the membrane should be protected from damage.
During installation of PRECON at lower temperatures and under certain environmental conditions, additional steps in the installation need to be followed to ensure that proper adhesion of the joints and overlaps is obtained.
1. MEL-PRIME is required to be used at all factory edge joints. MEL-PRIME is to be applied at a width of 6″ (152.4 mm) and allowed to dry prior to overlap of the adjoining sheet of PRECON. Following this, all areas of this overlap need to be pressure rolled for proper adhesion.
a. Apply HYDRALASTIC 836 or MEL-ROL LIQUID MEMBRANE (two-component) in the area to be lapped at a width of 3″ (7.6 cm) and roll press the overlapping PRECON while still wet.
b. Apply HYDRALASTIC 836 or MEL-ROL LIQUID MEMBRANE (two-component) at the termination of this overlapping sheet 12″ (30 cm) wide centered over the termination.
c. While the HYDRALASTIC 836 or MEL-ROL LIQUID MEMBRANE (two-component) is still wet, embed 12″ (30 cm) wide strip of PRECON and roll press into place. Then place DETAIL FABRIC from W. R. MEADOWS centered over the termination with 6″ (152.44 mm) on each side of lap edge.
d. Apply additional HYDRALASTIC 836 or MEL-ROL LIQUID MEMBRANE (two-component) on all terminations of the DETAIL FABRIC.
Please note that HYDRALASTIC 836 can only be applied in temperatures above 30° F (-1° C). MEL-ROL LIQUID MEMBRANE (two-component) may be used on end laps, penetrations and terminations down to 25° F (-4° C).
3. Prior to placement of the concrete, ensure that the substrate is clean, dry and frost-free. The temperature of the membrane at time of concrete placement needs to be above 40° F (5° C).
It is important to review each application as there may be situations that would require either of these procedures to be modified based on the project requirements. If there are any concerns during the installation, contact technical support for assistance.