Plywood – thickness determined based on need, rain or hurricane-resistant
Parting bead (if needed)
Anchors & screws 1 per side for every 6 inches
A thin sheet of plywood to serve as a rain guard
2 x 4-inch board – to mount rain guard to
½ inch thick parting bead (if needed)
Rubber window seal (ribbed)
Silicone glue
Instructions for Mounting and Securing a Door Dam
Mounting to Frame fig b
Cut plywood to match the width of the door frame and your desired height.
Mounting to Siding fig a
Add an extra 3 inches on each side when cutting the dam for siding installation.
Add a Base, if Needed
Some doors have an indent that may need filling. If so, cut the base piece ¼ inch smaller than the indent, and apply window seal on the front, extending it 2 inches beyond the base on each side. Place the dam over this setup.
Paint the Plywood
Use latex paint to cover the plywood, including all outer edges.
Align and Drill
Position the dam where it will be attached, and drill holes through the plywood into the frame or siding.
Frame mount – screws should be positioned to anchor to the frame and placed at the lower bottom of dam with screws being placed every 7 inches going up
Mounted to siding 5a- screws should be positioned to anchor to the structure walls and placed at the lower bottom of dam, with two additional screws placed at equal distances from the left and right screws; with screws being placed every 7 inches going up
Sizing Rain Guard Support
Attach a 2×4 to the top of the dam as a support for the rain guard. Use silicone rubber to seal it against leaks. Ensure the 2×4 is recessed below the wall’s top to allow the rain guard to sit flush with the dam, preventing water from pooling.
The rain guard should fit snugly between the door and the dam without any overhang (to avoid wind lifting it). Custom trimming may be required.
Apply Window Seal
Attach window seal to the dam’s outer edge using adhesive.
Optional: Extra Window Seal Layer – For additional sealing, add a second layer of window seal. If using staples, secure them to the rear portion of the seal.
Attach Dam to Wall
Secure the dam to the wall with screws.
Anchor to Bottom (If Mounted to Siding)
Use the rule of thirds to place screws along the bottom of the door frame.
Extra Security with Sandbags
Add sandbags at the base of the dam for additional stability.
Leak Test
Spray along the outer edges with a high-pressure hose to test for leaks. Avoid splashing directly on the dam. Check that no water seeps through.
