AIR-SHIELD SMP Primer (Technical Bulletin)

Print Version

AIR-SHIELD SMP AND THE USE OF AN ADHESIVE PRIMER FOR DIFFICULT TO ADHERE SUBSTRATES AND EXTREME ENVIRONMENTAL CONDITIONS

This document is to supplement the installation procedure for our AIR-SHIELD SMP. AIR-SHIELD SMP is a product that is designed to be installed without the use of an adhesive primer. However, for difficult to adhere substrates, or due to environmental conditions, it may be necessary for the use of a product, such as a primer/adhesive, to provide supplemental adhesion. In addition, design firms may only specify a sheet-applied material with the use of an adhesive primer. In difficult to adhere substrates or conditions, W. R. MEADOWS recommends the use of Holdfast 70 Spray Adhesive manufactured by 3M.

Independent testing has shown that the use of Holdfast 70 Spray Adhesive with the AIR-SHIELD SMP system provides a permeable air barrier per the ASTM E96 permeance rating. The overall vapor permeance of this assembly is dictated by the vapor permeance of the exterior gypsum board sheathing.

The use of primer is not recommended for every application, just in the situations that arise where there is concern with adhesion. In most cases, AIR-SHIELD SMP can be applied according to our current installation instructions without the use of primer and will perform successfully.

---

If you have any questions about this procedure, contact W. R. MEADOWS technical services at (800) 342-5976 or visit our technical services request form.

7-21