Chimney Waterproofing

Because they stand above the roofline of the home, all chimneys are extremely vulnerable to the elements, and nearly every chimney has visible signs of weathering. To stop the effects of weathering, contact the Indianapolis Brick + Ember Outfitters to schedule a chimney waterproofing. This will keep water from permeating the masonry on your chimney.

Although most are made of brick, concrete block and stone chimneys require slightly different treatment. First, you must understand what kind of damage can result from water penetration, as well as what kinds of waterproofing products exist and how they work:

Water damage

The brick on your chimney is held together with mortar, which is extremely porous. It often takes in water and can crack or erode as it swells and contracts—especially during the winter months. This can be dangerous to the structure of your chimney.

Spalling brick is quite common and can result in an entire re-building of the chimney structure. You can tell this is occurring when the faces of the brick flake and pop off.

If you see white salt that is built-up on the surface of the bricks, efflorescence has occurred. This happens after internal water has evaporated, and salt is left behind to coat the porous surface.

When water makes its way inside your chimney, the metal that provides internal structural support can corrode and rust. Before waterproofing, you may want an inspection to ensure there is no other damage like this. It will require extensive repair or rebuilding.

Waterproofing products

It is enticing to spend less money on inexpensive waterproofing products. The fact of the matter is, the more expensive a product is, the more effective it will be. Waterproofing material will break down when it is exposed to UV rays, so a high-quality product is the best way to prolong the effects of the waterproofing job.

Waterproofing products are normally made out of polysiloxanes or silanes. These chemicals create an electrostatic charge that becomes a barrier to prevent any water penetration. It is also vapor permeable. This means that the vapor created when you ignite your fireplace below can escape properly. Otherwise, it will build up and create structural damage, such as metal corrosion or crumbling of brick.

Brick + Ember Outfitters utilizes a product called ChimneySaver when performing waterproofs. ChimneySaver is able to do all that is described above: it reduces water penetration and is designed to expel water vapors that may pass through the bricks when the chimney is in use. It’s almost like a “skin” of sorts. Breathable  but effective, it doesn’t trap water, but expels it away from the porous masonry.

Chimney-Saver is available in both solvent (mineral spirits) and water-based formulas. The water-based formula is most popular and less expensive. However, because solvent-based formula soaks-in deeper, it is recommended for future re-applications.

Chimney crown and breast

The chimney breast does not go straight to the ground, but around structures like fireplaces. Because it lies at an angle, it can be exposed to the elements more easily. Therefore, a solvent-based product is typically used.

The chimney crown is made of concrete or mortar and is extremely porous. Its place at the top of the chimney makes it vulnerable to snow and rain. Cracks in the structure should be caulked, and the application of the waterproofing product must be done while the crown is wet. This will ensure the formation of a tight bond between the materials.

Non-brick chimneys

Concrete block chimneys are the most porous and in danger to water damage. More than one coat of waterproofing product is necessary. Additionally, instead of a water or solvent-based product, a solid-based treatment is preferred. This can come in the form of stucco or waterproof paint. ChimneySaver has special products for these situations.

There is a reason stucco can be used while waterproofing concrete block chimneys: Stucco does a fair job at repelling water as is. It does not require the extensive waterproofing that brick, concrete, or stone chimneys do.

Most stone chimneys do not work well with the chemicals in traditional waterproofing products and do not form the bonds necessary to repel water. A different product will need to be used.

Treatment day

Prepare for the chimney sweep to come with a sprayer and work from bottom to top. Cloth should be used to cover the roof and windows so that the waterproofing product does not damage them.

Waterproofing is not a one-time job. It will prove advantageous to pay extra for a second layer. On average, a waterproofing job will last about 20 years. However, depending on where you live and what kind of weather you receive, this will vary. It is always better to schedule a chimney check-up and waterproofing sooner rather than later.

Need waterproofing? Have questions? Contact us at 1-317-500-1250 or visit

Click here to view some of our chimney waterproofing work.