300119 Masonry Chimney Water Repellent - Siloxane Based, Non-Film-Forming, Breathable, and Transparent Waterproof Coating for Brick Chimneys & Other Vertical Surfaces - 1 Gallon

My brick chimney started leaking after 30+ years. Use of chimney cleaner and sealant made the job and fixed the leak and water stains formation! Great product, may be overpriced, but make the job. I recommend this product.

I had water leaking into my family room through the chimney. For some reason the upper ten rows of brick had become porous and with some occasional cracks. The real problem however was the cracked crown. The chimney footprint is approximately 65 inches by 30 inches.I removed the old crown by cutting grooves using a 4" diamond wheel in a small right angle grinder and chiseling off the old cracked crown. I screwed together a wooden form for the new crown so that it now overhangs the chimney by 3" on all four sides and approximately 2-1/2 ' thick at the edges. a drip groove was made using 1/4 x 1/4 wide wooden strips nailed to the bottom of the form approximately 3/4' from the form's walls.These pieces should be tapered so that they will be easily removed after casting the new cement. I used high strength cement tapered upward toward the chimney flue. Two layers of corrugated cardboard were used to create a space between the new cement and the flue. After casting the cardboard was removed and the space filled with silicone caulk. This is critical to allow for thermal expansion and contraction. The worst part of the job was hauling the 800 lbs of wet cement to the roof. Fortunately I own a ranch house and from my deck to the roof is only about 11 feet. I rented a a lift for the day that was easily hand cranked up to the roof line. It was well worth the price.After repairing all the broken and missing mortar joints I sprayed the entire chimney with the chimney water repellent using a garden sprayer. This process was very easy . My bricks were so "thirsty" that I ran out of liquid halfway through the job. Fortunately I started half way up the chimney side and worked my self up to the crown. I was just able to cover the top half with two coats.I followed this by filling minor cracks with the Masonry Crack and Joint Sealer made by the same company.I highly recommend both products.

I just applied it, so have no idea how well it works. It was easy to apply though and a gallon goes a long way. You should only need one gallon. This product seeps into the cement/concrete, then hardens. It's not meant to seal cracks or anything. You will need to apply a lot to be sure plenty has soaked in. I plan to use this on my sea wall in the fall.

Used the sprayer I use for weeds for this solution. Easy to apply. It does drip, and overspray is an issue, so covering the area around your chimney is essential. Some time must elapse before we find out how effective the product is.

I was at my wit’s end because every time it rained particularly in the winter my chimney would leak. The year before last I applied chimney cap to the top of my chimney in hopes the leaking would stop but to no avail but honestly I knew it needed to be done anyway. This fall I purchased the masonry sealant and applied it per instructions. This product has worked wonderfully. I rarely write reviews but felt like I needed to give it 5 stars and write this review because it’s such an awesome product.

No kidding, I didn’t believe it myself. I had a leak in my brick chimney and even repointed any bad mortar joints , and replaced my entire chimney cap ( 600# worth) and I still had a leaks during heavy rains... I followed the directions and no more leaks!!!. I even spilled a little on my sidewalk and 3 years later water won’t penetrate the spot. When dry you can’t tell, but when wet you can see the parts of the sidewalk where I spilled some.

We have bricks around the chimney that are porous. When there was a hard windy rain storm we would get water around the chimney in the attic. Once we began using this sealant on a yearly basis on the chimney bricks the water issue vanished.

Over the past few years I have had several issues with the chimney. I got a new crown and had the flashing replaced but it still leaked. I did a search on the web and found out that a chimney needed to be waterproofed! I applied ChimneyRx and the leaking finally stopped. The directions state that the chimney will be darkened if you over-apply the product, and that is true. Personally I didn't care if the chimney turned black as long as it quit leaking. The chimney has only been sealed for a few months but I have seen no sign of leaking through all of the summer storms we have had. A picture is covering the damaged area on the plaster wall that was damaged with the final leakage. For the first time since I bought the house 4 years ago, I now feel like I could fix that area without seeing it leak during the next storm.