How to Waterproof a Basement

Step 1: Relieve Hydrostatic Pressure (Block Walls Only)

If you have a block wall foundation you’ll start by relieving the hydrostatic pressure by drilling 1/2” to 5/8” weep holes into the hollow cells (4” to 6” in from each mortar joint) of your block walls at the point where the floor and wall meet. Solid poured concrete, brick and stone walls have no hollow cavities, therefore, you don’t drill weep holes.

Step 2: Remove Any Paint, Old Adhesive or Debris From Concrete

To properly bond and seal the system to the concrete floor the floor area along the wall approximately 3” wide must be stripped to bare concrete. To remove all paint and tile adhesive, use a metal drill attachment to nick at the surface. Do NOT use paint strippers or chemicals of any kind to remove old paint or adhesive.

Step 4: Layout System

Now, you’re ready to cut and trial fit the main sections along the basement walls. Place inside and outside corners where needed. Next, place full main sections end-to-end along the walls. Use a tin snips, hacksaw or miter saw to cut the main sections as needed. Layout the system just as it will be permanently installed.

Step 5: SealOnce™ Adhesive

Angle cut the tip just under the cone shaped end. This will give you the largest opening needed for applying SealOnce™ Adhesive to all surfaces. One tube of SealOnce™ Adhesive is needed per main section for proper installation.

Step 7: Installing Butt Joints

Using coarse sandpaper, rough up the ends of the main sections and back side of the butt joints. This will give you a strong bond between all vinyl-to-vinyl surfaces. Wipe the areas free of dust. Apply SealOnce Adhesive on both ends of the adjoining main sections.

Next, hook the butt joint at the bottom of the main section and “snap” in place at the top. It’s okay if a butt joint will not “snap” in place. The floor may be unlevel or baseboards my not line up exactly. Seal the edges of the butt joints and caulk the bottom to ensure there are no leaks. Clean up the edges of the butt joints using a putty knife.

Step 8: Installing Corners

Start by roughing up the ends of the main sections and back side of corner with coarse sandpaper. Apply SealOnce™ Adhesive on both main sections. Apply SealOnce™ Adhesive on bottom of the corner before setting in place. Inside corners are easy to install when dropped down from the top. Seal the corner’s edges and caulk the bottom for a watertight bond. Clean up the edges of the corners using a putty knife.

Step 10: Applying Finishing Seal

Important step! Working with one main section at a time, caulk the floor joint with enough pressure to force some SealOnce Adhesive under the system. Immediately follow to next step…

Step 11: Easy Water-Tight Seal

Important step! As soon as you caulk each section and before SealOnce Adhesive starts to thicken, slick down the finishing bead of adhesive our NEW Perfect SealOnce bull-nose tool. Notice how we raise the handle until the straight edge of our tool rubs flush against the face of the system (watch the video on how to use the NEW Perfect SealOnce Tool Kit at the top of this page). Holding the tool in this position slowly drag it all the way down the system leaving a perfect seal. The finishing seal is your water-tight seal of your system.

Step 12: Draining the System

There are two options when draining the SealOnce™ System. Option 1: drain into a floor drain. Option 2: drain into a sump pump. Drainage to a sump pump in most communities is the proper method of disposing of ground water. Be sure to check with your local building codes before draining to a floor drain.

Option 1: Floor Drain

Set the drain port in place and trace along the outside. Using a tinsnips, cut out the opening in the main section. Glue the drain port to the floor and seal the joint between drain port and main section with SealOnce™ Adhesive Note: drain port does not slide into the system, it butts up to the system.