Les Posted February 14, 2014 Report Posted February 14, 2014 These are photos of a brick veneer building in my town. Happens to be part of a complex that makes smallpox vaccine and highly guarded and secured. I could not get any closer and the guard was coming while I was taking the photos. The white stuff does not go away and get more pronounced during cold weather. The building is abt four years old. My thought is no drainage behind brick. A practical question is why nothing is being done about it. The State of Michigan owns building. It is not snow. Click to Enlarge 41.13 KB Click to Enlarge 56.64 KB Click to Enlarge 64.25 KB
kurt Posted February 14, 2014 Report Posted February 14, 2014 Very common in Chicago. Is it brick veneer on frame or load bearing masonry/cavity wall construction? Could be any combination of cavity full of crap, no drainage, whatever. We see it in middle of winter as it's the drying season; the building is drying to the exterior. Summertime, it just stays in the wall. You, me, and anyone else that looks at masonry knows what it is; the question is how to get rid of it. When we open these things up, the cavities are always sopping wet swamps. We've developed some products for venting cavity walls; so far, they seem to work.
Les Posted February 14, 2014 Author Report Posted February 14, 2014 brick on frame. this is a west elevation and the south and east elevations have no indications. in mid Michigan it is rare for drain holes/weeps.
kurt Posted February 14, 2014 Report Posted February 14, 2014 No answer for why it's on the west and not elsewhere; it'd only be the usual guesses.....WNW prevailing weather patterns, someone screwed up the west but not the S & E, etc., etc. Vented coping. Folks think it's about flashing and drainage; it is, but it's more about venting. Without venting, all the drainage in the world doesn't get you anywhere. Also, wicks are just plugs in too small holes. The presence or absence of wicks is a red herring. Honeycomb air vents set into head joints every 24" minimum. Of course, the building codes don't address venting of masonry cavities. It's another example of why masonry building codes are messed up. We know some of the guys at MIA and BIA that do the "engineering". Mopes shooting in the dark. Sorry, but it's true.
Scottpat Posted February 14, 2014 Report Posted February 14, 2014 I wonder if that is the production area and it is really warm and humid inside the building?
David Meiland Posted February 14, 2014 Report Posted February 14, 2014 Kurt, you got any pics of what those honeycomb air vents look like?
kurt Posted February 15, 2014 Report Posted February 15, 2014 There's bunches of different ones. We've used some called Cell Vents; you can get them out your way from Masco Masonry Supply. There are some poly mesh types that look like brillo pads that are good too. I like the mesh types because you can even pull them out if you want and actually get a look at the cavity. Essentially, a full head joint height filler that lets air and water pass. The only reason you want any filler at all is to keep bugs out, so I suppose leaving head joints open and covering them with a screen would work too. Google "masonry weep vents plastic"; a bunch of suppliers pop up.
kurt Posted February 15, 2014 Report Posted February 15, 2014 I wonder if that is the production area and it is really warm and humid inside the building? Maybe. I'd guess complete mismatch on mortar and brick; they're getting water in there in volume for that much efflorescence. Regardless, it can't be right someplace. Like I said, when we've opened those up, the amount of moisture in the cavity is remarkable. In summer, sometimes it's literally running down the walls, even with places with wicks and flashing. We've gotten kinda overbearing on the topic; walls gotta be vented, and there'd better be an outlet up top or it's not vented.
Mike Lamb Posted February 16, 2014 Report Posted February 16, 2014 Bad parapet coping details/flashing look to be the predominant problem with the efflorescence up high. If you get up close I'll bet you would find bad pointing and flashing details. Flashing is supposed to stick out to provide a drip edge but never does. Rowlock window sills? This just increases the chances of water penetration. Too much salt in the mortar maybe but too much water absorption/penetration into the brick for sure. Up and down ventilated drainage plane behind the veneer? Um, gag.
Jim Katen Posted February 16, 2014 Report Posted February 16, 2014 Kurt, you got any pics of what those honeycomb air vents look like? I'm not Kurt, but . . . Click to Enlarge 44.57 KB
Rocon Posted February 17, 2014 Report Posted February 17, 2014 Hard to tell it could be one of any of the options above including air leakage. Being a production faculty there could be humid air leaking from the building into the wall cavities.
SNations Posted February 17, 2014 Report Posted February 17, 2014 Hard to tell it could be one of any of the options above including air leakage. Being a production faculty there could be humid air leaking from the building into the wall cavities. There's an interesting new Building Science Corporation document -- BSI-075 -- that just came out last week. It's making the argument that this is from air leakage (exfiltration) above the neutral pressure plane. At the corners of the building something, probably wind pressure, is causing air leakage also. It's an interesting article (but aren't they all from BSC).
Bob K Posted February 23, 2014 Report Posted February 23, 2014 Here's a picture of a split face block wall with a vented coping installed on top: Kurt is instrumental in helping to develop this concept. Click to Enlarge 47 KB This is 2 days after a lot of rain. The moisture in the wall wicked out pretty quick. You'll notice where the line of through wall flashing is present. It is keeping the rest of the wall from exhausting through the top.
kurt Posted February 23, 2014 Report Posted February 23, 2014 Ha! Yeah, that was a soaker. Amazing what happens when you ignore the code and use common sense. Vent the damn wall, stuff dries out. Bob's figured out the system, I'm just a sounding board.
Jim Katen Posted February 24, 2014 Report Posted February 24, 2014 Here's a picture of a split face block wall with a vented coping installed on top: Kurt is instrumental in helping to develop this concept. Click to Enlarge 47 KB This is 2 days after a lot of rain. The moisture in the wall wicked out pretty quick. You'll notice where the line of through wall flashing is present. It is keeping the rest of the wall from exhausting through the top. Where's the through wall flashing? 8th course from the top?
Bob K Posted February 24, 2014 Report Posted February 24, 2014 Yes. It's at the 8th course. We also have a perimeter vent for the flat roof. It vents out through the 2 piece counter flashing at the roof termination. Click to Enlarge 70.31 KB
Bob K Posted February 24, 2014 Report Posted February 24, 2014 I just realized this photo didn't have the second piece of counter flashing. Here's the finished picture. Click to Enlarge 37.33 KB
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