Several homeowners ask me about waterproofing their masonry chimney and one of the most common questions is, “Can’t I just do that myself?” My reply is generally the same, “Sure you can as long as you have the right equipment, material, and aren’t afraid of heights.” Water is the biggest cause of deterioration in masonry chimneys. I’m not going to tell you that you can’t maintain your own chimney to save some money. In fact, here’s a step-by-step guide to waterproofing your masonry chimney – and I’m not going to sugar coat it.

Step One – Safety

Please don’t skip this important step.

  • Use eye protection in case of mist being blown back toward your face.
  • Use gloves when handling all chemicals to prevent chemical burns or irritation.
  • Use a ladder that is comfortable to climb and reaches your roofline. Make sure to have a friend available to help or make sure the ladder doesn’t fall while you’re ascending or descending.
  • Lastly, make sure you’re comfortable standing or at least sitting on your roof. Don’t attempt this process on your own if you’re uncomfortable being on your roof or fear that you may fall.

Step Two – Measure

Just like you hear from carpenters, “Measure twice, cut once.” But we aren’t cutting anything unless we have to. You do need to know the surface area of your chimney though; because you need to make sure you have the right equipment and purchase enough materials to get the job done right the first time.

Step Three – Clean

Chimneys are dirty and you don’t want to seal in mold, rust, creosote, smoke stains, or anything else that will look nasty for years. Purchase a good cleaner that is specifically designed for use on a masonry chimney. Follow the instructions on the bottle to prevent personal injury and any ill effects of improper use of the chemical.

Step Four – Protection

Lay sheets of canvas drop cloth or another absorbent material over the shingles to prevent damage or discoloration of the shingles. Make sure to protect any siding or windows that may catch the overflow of spray.

Step Five – Repairs

Mortar deterioration is a very serious issue and must be repaired as quickly as possible. All cracks and damages must be addressed to prevent further damage. Serious damage to a masonry chimney could result in collapse and damage to the structure of your home. Contact a contractor if you see damages that you aren’t absolutely sure you can repair on your own.

Step Six – Repellent

Purchase a water repellent that provides the protection you need. Make sure to purchase enough to cover the surface area of your chimney x2 because you need two coats for a good barrier against water. Follow the instructions on the bottle. Here are a few tips to help achieve an even coat on the entire surface of the chimney:

  • Spray or brush on the repellent, bottom to top, following the manufacturer’s instructions.
  • Apply a flood coat, allowing it to run from top to bottom, working in a six to eight inch area.
  • Use a soft bristled brush to agitate the wet surface and work the repellent into difficult areas.
  • Apply the second coat in three to five minutes.
  • Allow to dry at least 6 hours.

Over-application of most repellent products can cause the surface area to darken slightly.

If you’re the do-it-yourself type and want to save money by sealing your chimney yourself, and still feel like you’re up for the task, go for it! You’ll probably do an amazing job and I applaud your efforts. If you’re on the other side of the fence and this sounds like too much work for your busy schedule or you simply don’t want to do it yourself, give me a call. We’ll schedule a consultation, quote, and go from there.