MasonryDefender Chimney Crown Sealer - Brushable Waterproof Sealant Prevents Leaks - 1/2 Gallon

This stuff works.

My chimney used to leak like it was emotionally unstable. Rainstorms? Cue the buckets. Snow? Instant anxiety. Then I found this crown sealer — thick, brushable, and clingy in a way that actually helps your relationship with your roof. It spreads on like frosting, fills every crack like it’s got a grudge against moisture, and dries into a rock-solid barrier that laughs in the face of rain, snow, sleet, and freeze-thaw drama. Application was surprisingly easy — just grab a brush and channel your inner Bob Ross. Took me less than an hour and I didn’t even have to Google “how to fix a chimney leak” afterward. Weeks later, storms rolled through and… nothing. Dry as a dad joke in the desert. If your chimney is crying for help, this is the therapy it needs — easy to apply, built to last, and tough enough to survive whatever the sky throws at it.

Easy to use. Only needed 1/2 gallon size to put 2 coats on chimney cap. Still had enough left over for touch ups. Waiting to see how it holds up.

This sealer seems to have done a great job in sealing up the very weathered and cracked crown on my 50 y.o. chimney. You have to apply a pretty heavy coat, and then a second coat after a few hours, but doing so filled up all the myriad cracks and chips and effectively made it waterproof, probably better than new. I'm hoping this will survive the elements for a lot more years. It seemed a bit pricey but if it lasts it will be worth it.

While long term results can't be guaranteed, initial impressions are very good. As long as you prepare the surface correctly, this stuff will stick well. One negative review I saw showed the product had been applied to a very dirty surface. Just like painting, surface prep is one of the most important steps in the process. As well as a chimney cap, it was applied to the top of a small retaining wall along our driveway and looks a lot better than bare concrete.

just as described, it worked well I painted the cap of my chimney. It's nice and solid and a rightness about a year after I put it up. It's still working fine.

I did not realize how bad a shape my chimney crown was until I was able to get view from the top down. There were small chunks and cracks on the top that I could not see from looking up. The product is thick when applying, just get a couple of good paint brushes and take your time. It's a good idea to tape off the bottom and other areas if you want a clean, professional look. Highly recommended for do-it-yourselves.

I got a quote from a chimney expert wanting $300 to “fix” the top cap by applying a flexible sealer. This product adheres to the existing top cap (after cleaning/surface prep) easily using a standard paint brush (I used a2 1/2” angled brush). Started at the bottom and worked my way to the top on each corner. The consistency of the sealer is like a gritty mastic that grabs the surface yet smooth out nicely. The surface temp has to be above 40 degrees Fahrenheit and no rain within 6 hours after application. So far, I’m very pleased and I think you can’t go wrong with this product. If your existing top cap is in poor condition, say cracks greater than 1/4” or missing chunks - my recommendation is to replace with new mortar top cap.

The winter will tell, but so far, has set well. It was easy to use, with clear instructions. The stuff is like thick toothpaste. Coverage is as good as advertised.

Had a cracked crown that really leaked down into the chimney cavity. Found this stuff on Amazon. Got a chimney guy here in Australia to apply it while he was cleaning the chimney. Since then we've had record rain and no leaks so it must be working. The chimney guy in Australia hadn't heard of it before but was really impressed and did a deal where he took the remaining and reduced my bill! Time will tell if it lasts but so far it's saved me at least a few hundred dollars.

Wire brushed the cap, then applied only one thick coat as the temp was falling and rain was in the forecast. Luckily the rain held out for 5 or 6 hours and it all went smoothly. Went back up on the roof a week later and it was completely cured and bonded perfect. Used about 2/3rds of the pail will apply second coat in the spring. Time will tell if it lasts. Update...After a long cold winter it was perfect, used the rest of the pail to fill in any depressions etc in early spring. Looks great.

Seems like an excellent product ….my chimney will let me know over time. Expensive and overpriced but nothing better available.

Very happy with product. Nice to work with. Ken