Resisto Joist Guard

If you’re looking to maximize the life of your new deck, Resisto Joist Guard is a product you should definitely familiarize yourself with. Manufactured using an asphalt mastic adhesive, Resisto Joist Guard is designed to self-seal itself around screws and nails, blocking pathways for water to infiltrate into your decking. Designed to be applied to the top of deck joists, this unique formula acts as a waterproof membrane, preventing wood from rotting or decaying, while simultaneously denying water accumulation under your decking boards.

How it works

The key to this product is the corrosion barrier created upon application. If you plan on adhering galvanized metal or aluminum to your pressure treated lumber (rated ACQ, CA-B, or ACZA), simply apply Resisto Joist Guard to the top of your deck joists from end to end. This creates a physical barrier between the framing of your deck and the surface decking above, preventing the chemicals used in the treated lumber from eroding the metal surfaces over time. Though most commonly used to protect metal hangars, deck plates and sill plates, it can also be applied anywhere treated lumber is used for added protection.

Surface Preparation

Before using Resisto Joist Guard on your deck, be sure to thoroughly clean and dry all surfaces, ensuring they are free of any oil, grease, or debris. To ensure maximum results, flashing should be applied in temperatures 45° F or warmer. If you plan on working in temperatures below this threshold, using a construction-grade adhesive is recommended. If optimal adhesion is not being achieved or if application proves difficult, a variety of fasteners can be used to attach Resisto Joist Guard mechanically.


Once your joist surfaces have been sufficiently prepared, cut Resisto Joist Guard to the proper length, being sure to center over joists. Remove the attached release paper and press flashing securely in place. Firmly crease and fold Resisto Joist Guard material over both sides of the joist to adhere into place. When over-lapping material end to end, a minimum 2” overlap is required to achieve maximum results. If you are planning on overlapping side-to-side, a minimum 1” overlap is recommended. If being used as an ACQ barrier, Resisto Joist Guard can be applied either to wood or metal surfacing. In all applications, small rollers can be used to form a more airtight seal between lumber and flashing.

More information at manufactures website