Concrete block is a porous material and must be waterproofed to prevent seepage. Moisture seeps gradually through concrete and causes mold growth and deteriorates concrete and mortar. Building codes require builders to waterproof exterior concrete block below grade (ground level), but local code varies greatly in enforcement and minimum requirements. Additionally, code says nothing about interior concrete surfaces. To be safe, have your sub-grade exterior wall professionally waterproofed and seal the interior yourself to ensure a watertight wall.
Things You'll Need
- Stiff-bristled brush
- Concrete sealer
Scrub the surface with a mixture of warm water and detergent to remove dirt and debris. Dry with towels.
Disinfect the wall with a mixture of household bleach and water (1/2 a cup of bleach per gallon of water) to prevent mold growth. Allow the wall to air dry.
Apply commercially available concrete sealer to interior surface using a roller, paint brush or sprayer. Apply sealer liberally and evenly, moving from top to bottom in long, even strokes. Completely cover one wall before moving to the next.
Allow sealer to dry. Drying time will vary according to environmental conditions such as room temperature and humidity; check after an hour or so. Apply a second coat, and allow it to dry. The second coat should take less drying time than the first coat.
Tips & Warnings
- Most block foundations are waterproofed by the builder during construction.
- Check periodically for signs of moisture seepage, such as musty odor, mold growth and dampness.
- Photo Credit concrete wall image by Lela Obradovic from Fotolia.com
How to Seal a Brick Wall
Brick walls are sturdy structures that are not only functional in weight support, but ruggedly aesthetic. Brick walls can be found inside...
How to Waterproof Cinder Block Basement Walls
Your cinder-block basement wall must be waterproofed to provide a proper home environment; otherwise, water will seep in through the walls of...
How to Seal a Cinder Block
Using concrete or cinder blocks for exterior basement walls is a typical construction practice. These porous blocks allow moisture to move through...
How to Seal a Concrete Block
Concrete block is a commonly used building material for wall and home construction. While it is a strong and durable material, concrete...
How to Waterproof Bathroom Walls
Although bathroom walls are made from different materials, the majority are covered with porcelain tiles. Porcelain tiles not only give your bathroom...
How to Stop Water Seepage in your Basement
One of the most common problems in homes that have basements is water seeping inside and pooling on the floor. Several things...
Instructions for Using KW Block Sealer
K&W Block Seal is used to repair leaks and holes in engine blocks, gaskets and radiators. It is an additive that will...
How to Seal a Concrete Block Foundation
Concrete blocks are naturally porous, and when they are laid into a block foundation, they tend to absorb water from the surrounding...
How to Patch an Exterior Concrete Wall
Concrete walls are widely used because they are easy to form and durable once they set. After the concrete has cured, however,...
The Best Water Seal for Concrete Blocks
Concrete sealers are an important part of any concrete block installation, whether you are looking at your basement foundation or a backyard...
Should You Seal Concrete Walls?
Concrete walls are not like rock or stone. Concrete is porous and water can seep through the wall and can even be...