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

We don't have any leaks but the contractor who built our house recommended applying a sealant to the exterior stonework, and particularly the stone chimney. I researched it carefully and this product was consistently recommended and highly rated, so we selected it. The reviews were spot on: this stuff works! I'm providing a photo of the stone and grout at our chimney, now 5 months after application. It has been pouring rain for 5 days and the water is still beading up on the stone and grout surfaces. Get it, you won't regret it. BTW, I rarely submit reviews on Amazon, but this product is SO good, I thought the manufacturer deserved this review. Kudos to them.

Works as advertised. I sprayed it on 5 years ago and no more water intrusion

This stuff saved my chimney. Easy to put on and really stopped the spalling that was taking place. I would recommend this to anyone having issues with a chimney taking on water or spalling. Just put it into a garden sprayer, put some old blankets down so you don't stain your roof, and spray starting at the bottom slowly working your way to the top. I had enough to repeat each side multiple times after letting it set a few minutes. We have had numerous storms since and no more brick pieces lying everywhere afterwards. This stuff really works!!

Easy to apply hopefully it will last

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 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.

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.

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.