“We can look at a masons work to see if its good how in the hell can I look at a lab 's work and see if its good "

 

Py, I’ll give a quick answer.  I think judging a mason and a lab are really not that different.

 

1)       Instead of just asking for a mortar analysis decide what kind of questions you have.  Ask all of those things you mentioned (e.g.; can you identify hot-mixed tabby and bull’s blood?).  If two labs answer your questions differently than challenge them on each other’s answers.

2)       Ask for a sample report from a few labs.  Compare the quality and decide who gives you the level of information you’re looking for.  I’m always ready to provide a sample of our work and even volunteer it when I hear the potential client is uncertain about what they’re purchasing.

3)       Look for transparency.  If the report says the mortar is a portland lime with a 1 : 2 : 8 ratio, look to see if they explain how they determined it was a portland lime and what calculations they used to come up with the ratio.  Answers shouldn’t magically appear without supporting information.  You’re paying for the analysis and you have a right to know what you’re paying for.  It may sound like mumbo-jumbo to the general reader but it makes the lab accountable as their work can always be checked by another lab.

 

Granted it ain’t foolproof but neither is choosing a mason no matter how good his mock-up looks.  As for the cesspool, I’m usually asked to put on my waders and ferret out the masonry cement jockeys once their mortar starts falling out of the joints.

 

John

 

 

" Over here I can get you a cheap little stucco ....and oh boy will you be  stuck-o"

Groucho to cheeko  while selling Fla real estate  in Coconuts 1929

If you don't want to drop the big bucks get John Ashursts book "cements and Plasters "Donhead publishing or British Heritage  very nice; simple ; more for repairs of historic British plaster but sometimes its just the knowledge that people are looking for  

Lab debate
many thanks for the lab information; upon further questioning the architect just wanted something on paper for his file for a 1920s university campus building
and those of us in the field always think lab tests are fairly simple affairs
but in reality it appears from our interaction here that there is a lot that gets overlooked; thrown out, or just swept under the rug ......
I know for example that unless you know what to look for
natural cement will never be identified as such .....nes pas ? 
I know many labs won't recognize or comment on the setting properties of 19th cent brick dust;  or sharp red sands with high Fe content
then there comes the question of  the lime
and how reactive it is?  Tabby for instance was poured  "Hot "
how do we know that ?
or plaster had bulls blood  ;or stucco mixes urine or manure for that matter

I would imagine for instance on a project like Jefferson Davis 19 cent beach house and libray here on the Mississippi coast (Beauvoir) severly damaged by Katrina  all this is very important science;

How does the state or the owner know what lab will give him accurate evaluations?  If we only get wet analysis   it not suspect?
We can look at a masons work to see if its good how in the hell can I look at a lab 's work and see if its good "
Is it just track record? Sometimes I think (like my architect)all anybody wants is the paper and letterhead to give mouth service to the owner
But the problem is deeper than that 
Believe it or not I have also seen big (but not necessarily historic)
General contractors go out of their way to frustrate architects who have little or no experience let alone patience with historic materials  ignore the lab results  and accept "As equal" to put up what they please.     
I don't know if this flim flam  happens with wood;
I know it happens to windows and mortar
"but down heah "its a problem now that the restoration market
is being flooded by out of work contractors who have
remolded homes and call it restoration
and the state guidelines for protecting such projects and the craftsmen who traditionally work on them are vague  so what happens is everybody gets thrown into the cesspool  of quasi qualified  low bidders  to fight it out 
I rest my case ..now if it pleases the court I will go out
and bounce with p'nut on the trampoline  Py


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