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

Works for 1 year. I sprayed it on my shingle roof it’s self along with my stone chimney.

Goes on easily. Too early to tell how it works , only been on for one day. Update: water doesn't bead up like it shows on the web sight. I question if it's going to do what it claims

I patched every place I could see with Mortar sealant and I still had a leak. So, this product worked in stopping the leak. I purchased a new pump-up spray jug and sprayed down the chimney and we had a small shower and No leaks, the next day it rained almost 2 inches and "NO LEAKS". Hip-Hip Hooray. Note: I was told it might change the color the bricks, so I did the entire wall along with fireplace, and unless you're an expert - I can't tell it did anything.

Easy to apply hopefully it will last

I've been having trouble with water seeping through my fireplace chimney. I painted this on during the summer, and so far it seems to be holding. It's completely clear and didn't leave any visible signs of having been applied. I think I'll start using it every year just to place it safe.

I have replaced the flashing dozens of times. Then I had a roof guy mention to me... have you sealed your chimney? I was like.... hmmm then I saw this online and decided... what the heck it is not much to try it out. I did it myself with a garden sprayer. Then the first rain came and then another. This last one was a hard rain with winds... I even had dragged a kiddie pool in the attic to catch the drips... and I went up after I had sprayed the chimneys.... I looked in the kiddie pool and NOTHING. NO WATER. I was shocked. It worked. This had been going on for years and just like that it stopped. WOW. A product that actually works that you can do yourself and don't have to hire anyone to do it. YEAH!!! Thank you!

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 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.