Diagnosing parapet problem?
I noticed some deterioration on our parapet wall, and am trying to figure out what we need to do to fix it. In some spots, the brick face seems to have popped off. My guess is that some water is getting into the brick around the coping stones at the top of the parapet wall….
I noticed some deterioration on our parapet wall, and am trying to figure out what we need to do to fix it. In some spots, the brick face seems to have popped off.
My guess is that some water is getting into the brick around the coping stones at the top of the parapet wall. I do not see any evidence of water leakage on the interior. Any advice on how to deal with this would be much appreciated.
Thanks.
The bell tile parapet cap should be thought of as aesthetic only. It cannot hope to keep moisture out of the wall. Capillary action is just one way that moisture can get past the tiles. What matters is how the roofing membrane and metal cap flashing were installed, what has been done to them since, and how they have held up over time. A roofer needs to remove a tile here and there and inspect to answer these questions. Once the parapet has been properly waterproofed, the bell tiles can be replaced and remortared, and no fasteners that will penetrate the waterproofing should be used to do this.
This image caught my eye because of the bell tiles. I’m currently working on a new roof for an old building that has these same tiles on the parapet (and has the same moisture problems that UWS has), and I need to find a source to replace the ones that are broken. UWS, I’d be very grateful if you would be willing to go up and look for a manufacturer’s stamp on your tiles. Chances are slim that their profile is exactly the same as the ones I need, but maybe the manufacturer of yours can guide me to others.
DD
We have similar problems on our back brick wall with a Thorocoat cover. We looked into repointing the whole thing, which would be super-expensive, or we could reapply another coat of Thorocoat, which seems stupid since, as other said above, its temporary and bad for the brick/moisture.
Anyway, we just gave up, thought we could live with it for a few years and then re-approach the problem.
Thanks everyone for the thoughtful and helpful comments. The wooden terrace structure on the extension roof is a wreck, so we will be looking to locate and eliminate the leakage when we get that re-done.
Anyone have suggestions of contractors who can fix the brick, do the roofing and build a new deck?
Thanks again.
That’s not bad at all — in fact it’s very typical. Just hire somebody to scrape all the loose crap off the wall, fill the holes with cement, and re-Thorocoat the entire wall. Water probably isn’t entering from the coping stones, but you could seal the joints between them as well if you want.
Remember we’re talking about a hundred year old brick building and it’s possible the bricks used to construct your house weren’t even new at the time of construction. It only takes a little bit of water or even humidity getting inside and, Kapoof, old brick will turn to dust.
Of course, it’s better to properly repoint brick walls and not Thorocoat them, but since it’s already been done, it’s not worth the massive amount of work required to try and scrape off the Thorocoat. Not to mention that Thorocoat is supposedly designed to allow the brick to breath anyway.
The best solution is to remove the paint . Hot moist air could be migrating from the interior, is there a radiator in that corner? The inside of the parapet may need to be re pointed, the coping stones could be leaking or you may have a small leak in the roof. It doesn’t look like a serious problem though, the brick just can’t breath.
I’m guessing—but obviously, it’s entirely speculation—that there may once have been an iron railing set into the top of the brick, now covered by the terra cotta coping and any mortar used to hold it in place. In that case, and without flashing and weepholes, water trapped under the coping will infiltrate the brick from above, and seek an exit producing spalling and discoloration.
Senatorstreet is right on, the paint is trapping moisture and causing the brick face to spall and the paint to blister.
I doubt though, that this much water could be trapped just by water seeping back under the terra cotta cap by capillary action. There are some dirt streaks where this is happening, but the fact that the paint is failing across the wall suggests that quite a bit of water is getting back there.
You’re certain there is no chance of water entering the masonry from the interior side? And are those patch or repair marks under the paint near the first (lefthand) greenish splotch? There is definitely something peculiar about the way the paint is selectively failing, I wonder if the paintjob was a response to cover over some earlier patching due to water damage (one of the things Vinca suggests). It looks like that also where there’s a change in texture about a third from the bottom of the image.
Not knowing anything else, I’m throwing a guess out there that there’s a small leak allowing water vapor into the wall from the inside of the parapet or more likely from the deck. Any chance of that?
Often, when you see paint or Thorocoat covering brick, it’s because of an effort to hide or delay the need for major masonry repair/repointing. Take a look at this link, and/or hunt for similar: http://www.managemyhome.com/mmh/answers/Answers.action#l4q112257
My guess is that delamination is due to a non breathable paint having been applied over the brick and moisture accumulating under the paint and into the outer layer of the brick.
Brick (and sandstones – limestone and brownstone) is soft and should never be painted with anything that can not breathe.
The verticle lines that are visable in the picture look to be some form of water that may be the cause of water at the surface that is penetrating into the cracking, peeling paint.
My guess here is the morter/caulking under the terra-cota is failing allowing water to leak under it and should be attended to.