21 March, 2009

Historic Masonry Seminar -- Repair, Remediation, Cleaning


Eight o'clock in the morning is probably not "early" for most of you; but if you are an independent contractor who is used to getting up at noon and going to bed at five a.m., it's pretty freaking early. Still, Ted and I managed to drag ourselves up in time to attend a free morning seminar at the Garfield Park Conservatory called "The Care and Maintenance of Your Historic Masonry Home," hosted by the Historic Chicago Bungalow Association and Neighborhood Housing Services of Chicago. It was well worth the effort.

I'll post the class description here, because they do have another workshop coming up in April.

From greystones to bungalows, Chicago residential neighborhoods are defined by brick and stone buildings. However, many homeowners are uncertain of how to best preserve, maintain, and repair their historic masonry homes. Presented by Mario Machnicki, president and founder of Marion Restoration, this workshop will cover: common conditions and deterioration problems, identifying priority repairs, establishing a scope of work for masonry repair projects, best practices for cleaning and tuckpointing, and financial resources to fund rehab projects. With over 30 years of experience, Mr. Machnicki has been featured in This Old House and The Chicago Tribue.

Next seminar:
Saturday, April 25, 10 a.m. to 12:30 p.m.
Avalon Public Library
8148 South Stony Island Avenue
Chicago, IL 60617
RSVP to greystone@nhschicago.org, or Blanch at 773-522-4637
We learned a great deal about masonry in general, and Chicago building practices in particular, during the two-hour presentation, which was followed up by a Q&A where they welcomed specific questions about your own building. It covered the types of building materials commonly used, such as limestone, sandstone, and brick, and the types of mortar and style of mortar joints. It also provided links to some excellent online preservation briefs, including:

Assessing Cleaning and Water-Repellent Treatments for Historic Masonry Buildings


Repointing Mortar Joints in Historic Masonry Buildings

Dangers of Abrasive Cleaning to Historic Buildings


There are nearly fifty briefs in all, on a wide number of topics, so check it out.

The key to preserving a building all comes down to one thing: the mortar. (Well, two things, the other is keeping out water.) To ensure that The Box House will last another eighty years, we should be repairing our masonry with like materials, and get our mortar matched exactly. We kind of knew that already--although, amazingly, most contractors do not seem to--we just needed more direction in how to go about mixing new mortar and where to get our mortar analyzed. There is a company called U.S. Heritage Group, Inc. that can run a chemical analysis on our mortar and give us the exact composition.

A previous owner repaired some of our mortar joints with Quikrete--we found the empty tubes in the basement. This product, like many modern mortars and cements, is rigid and doesn't breathe. Areas of our brick garage have a layer of cement smeared on the surface, which now prevents it from breathing. It's probably only been a few years since these bungles were performed, but we're already seeing issues related to these bad repairs--spalling, cracking, efflorescence. If we don't remediate them, over time the brick--which can no longer expand with weather variances--will completely break and crumble against the inflexible mortar.

Other things we learned which are directly applicable to our building:

The paint on the walls of our brick basement can only be removed chemically. It is a tedious process, but he recommended three products to try: Soy Gel, Prosoco, and Dietrich. Under no circumstances should we use mechanical means. What surprised the two of us is that sandblasting is actually illegal in Chicago. Not that we would try it, the historic brick is too soft, but it's illegal because of the lead dust the paint might contain, which will coat the neighborhood. We were shocked because we had just read an article in the Tribune about a couple who had renovated their basement by sandblasting the walls. It seems to be a common practice; I guess contractors either don't know about it or assume they won't get caught.

I neglected to ask specifically if we could use those same chemicals on the limestone outside, which still has its coating of paint because I haven't decided exactly how I'm going to remove it. We've been simply watching it flake off and "helping" it along.

However, Machnicki did mention that these same companies sell detergents to clean exterior masonry; the trick is to soak your masonry first so that the chemicals don't soak in, and to rinse it thoroughly with water. He mentioned a 900 psi as being okay, but he also strongly cautioned testing areas when cleaning first. Yellow brick, for example, is extremely susceptible to damage, and he's seen brick that has been bleached out from improper cleaning. We have some green biological growth on our portico, and he recommended trying water first.

Someone else asked about finishing off a brick foundation basement, and we were told that the furring strips should be placed an inch away from the walls to allow the masonry to continue to breathe.

Another person asked about insulation, but we were told our buildings didn't need it. With walls a foot thick, it wasn't necessary. He did mention insulating plaster, but we didn't get the chance to pursue the topic. I'm not certain what that means.

All in all, it was a very enjoyable morning--definitely worth getting up at the ungodly hour of eight.

Plus, we got to spend some time at the Garfield Park Conservatory, which just celebrated its one hundredth birthday.

Don't let this picture fool you; it's still pretty chilly in Chicago.

4 comments:

Andy said...

Yeah, about that...sorry I didn't respond to the FB message...just been hectic! I WOULD HAVE said: I wasn't planning on going to this because I had actually done a masonry workshop that HCBA hosted a couple years ago, at their Wolfram Model bungalow, before they fixed it up. They actually showed us, hands-on, most of this stuff...mixing your own mortar, grinding out the old stuff, proper tuckpointing procedure, etc.

Such that, someday, at some point, I plan on repointing the entire face of my bungalow...it needs it, badly.

But it sounds like what you learned was the same pointers and tips they gave at our workshop (and it was different guys).

I am going to the gardening one they're having in early to mid April, because I'm not going to miss that one, for sure!

Green Fairy said...

Wow, sounds like your class was even better--we didn't get to do any hands on stuff.

We'll be doing the repointing ourselves, too, when it comes down to it. Except for rebuilding our parapet; that I want to leave to a professional, I think.

I was toying with the idea of going to the April 8th session of the gardening one; our yard needs a lot of work, especially since we tore out all the overgrown juniper bushes.

Why S? said...

You're brave. Eight is early for me too. Way, way early.

Mona said...

This sounds like a great seminar for homeowners. I'm a great stone lover and woud be interested in attending something like this.