Historic Masonry Repair Article? 1

[druminman]

We frequently get calls to evaluate various problems with older load bearing brick masonry structures, and more often than not, one of the problems is the use of modern cement mortar when re-pointing. Typically, our scope is not such that I can offer solutions beyond "consult a mason familiar with historic masonry materials and methods".

I am looking for a trade article from a journal or magazine that explains the issues well enough that I could offer to the clients to provide a little more explanation and a lot more detail on appropriate materials. I know I've read a couple such articles in the past, perhaps in Old House Journal or Fine Homebuilding or such, but I can't seem to locate any that aren't very technical now.

Thanks in advance,
Patrick

 

[SLTA]

How about the preservation briefs?

http://www.nps.gov/history/hps/tps/briefs/brief02.htm

 

[SLTA]

Here's the main page:

http://www.nps.gov/history/hps/tps/briefs/presbhom.htm

 

[druminman]

Thanks a lot for the suggestion, Slta.

Those are great, and I use them as a reference often, but I was hoping for something more succinct that just provided the basics.

 

[dicksewerrat]

Contact the bricklayers unions and apprenticeship training schools around you for old books on mortar mixing instructions.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[concretemasonry]

Unfortunately, most people think of using the "bigger hammer, the better" approach and specify Types, M, S or N mortar stupidly thinking stronger is better. The important thing is compatibility since you are dealing with a wall that is a site built masonry structure and not a random collection of materials used, hoping they are compatible.

Unfortunately the term "loadbearing" sends chills up the spine of an uninformed engineer.

If you look at the first note in the Appendix for the ASTM C270 mortar specifications, it clearly points out that there things more important than strength because for masonry walls. I have seen hollow concrete masonry prisms made that tested 4800 psi using 2400 psi mortar (Type S, not even Type M), so that underscores the lack of importance in the strength of loadbearing masonry construction.

You must use the "mortar of the time" that is compatible with materials for a truly balanced finished wall that works in unison and is durable rather than having too strong a different mortar that causes durability problems. For an older, soft brick, a sand/lime mortar could be more desirable.

I think the BIA would be better than the Bricklayers Union, but the union still has some history around despite the low number of masonry restorers in the restoration industry. Most of the problems from restoration come from deterioration/weathering due to incompatibility of materials.

Dick



Engineer and international traveler interested in construction techniques, problems and proper design.

 

[dik]

Slideruleera website has an article I prepared on historic brick...

Dik

 

[druminman]

That's the article I was looking for! Thanks Dik!

 

[csd72]

There are plenty of articles in the uk on this by the BRE.

 

[dik]

University of Sheffield has done a lot of research on this...

Dik

 

[dik]

BRE?

Dik

 

[msquared48]

Concretemasonry:

In my way ov viewing things, all Masonry walls are load bearing in the sense that their weight alone is freqently higher than the load then support, or bear.

I know, picky, picky... neverftheless, just a thought.

Mike McCann
MMC Engineering