chimneymasonryroofwaterproofing
Getting ready to repair the chimney crown, using this Family Handyman article as a guide.
On our chimney, there is a line of bricks around the crown that have exposed holes in them. The holes are facing upward, and I imagine that they could potentially allow rain to seep in.
Should those holes be covered/plugged at all? Potentially with the chimney crown sealer?
The answer is going to depend on whether or not you intend to ever use this flue again. If it is never going to be used, I'd seal it up with a solid cap, mortared down. if you think you may need it again, then a simple rain cap with a vermin screen would be fine.
A mid size rotary hammer (SDS plus or SDS max) with a point and a chisel will break the bricks out. Have an extra manual chisel, mason's hammer and prybar on hand (to free the rotary hammer, when you get carried away and plunge too deep). Hand, eye and head (hard hat) protection are advised. Dust masks, too.
Best Answer
Those holes should be filled with at least with masonry cement. You can get it at the big box stores, it is sold in 60lb bags for a few bucks. It does not matter whether it is fast set, type S, it just needs to be masonry cement. No need to mix the whole bag. A 5 gal bucket to mix it in and a Tupperware(r) container or large coffee can will hold about what you need. Get a margin trowel, also at the same store you get the cement. Mix it to a peanut butter consistency and carefully place it around the edge of holes. With a little coaxing it should go in. DO PROTECT the roof, it will stain it, or keep a garden hose on the roof with you. You will need something to keep the roof clean from the chimney crown material.
Do not let the material you use to protect the roof be the same material that throws you off the roof. Stepping on a loose tarp will do it fast. Plywood acts like a skateboard. Be careful!
The way the chimney crown material works, you may only need it to get hard overnight before you apply the chimney crown material