Mortar is not really flexible. It has no significant elongation or recovery
characteristics compared to truly flexible materials like polyurethane
sealants. What we mean when we say flexible with regard toime mortar is that
it has more ability to deform under stress than harder Portland mortars,
particularly when wet. That is Low Modulus of Elasticity (for mortar).

I apologize to the group if I tend to get fed up, from time to time, with
people who make decisions based on nothing more solid than "it feels right",
a conclusion which is not unheard of in histo presto circles where a warm
fuzzy buzzword and some oversimplified (often to the point of incorrect)
selling points are substitutes for actually knowing what the hell they are
talking about.

Modulus of Elasticity is more important than compressive strength, tensile
strength and flexural strength, and it probably deserves priority, in most
cases, over the overblown Holy Grail of Permeability. Maximum permeability is
not nearly as critical as low modulus of elasticity. Or high bond strength.
Or low shrinkage.

Edison Coatings, Inc.
M. P. Edison
President
3 Northwest Drive
Plainville, CT 06062
Phone: (860) 747-2220 or (800)697-8055
Fax: (860)747-2280 or (800) 697-8044
Internet: www.edisoncoatings.com
E-Mail: [log in to unmask]

---------- Original Message -----------
From: Ken Follett <[log in to unmask]>
To: [log in to unmask]
Sent: Fri, 3 Jan 2003 15:01:44 EST
Subject: Re: Healing Lime Mortar

> While it is heretical to suggest ...
>
> Michael,
>
> All the more reason to bring up engineering principles on BP where
> heresy in pursuit of knowledge is the prevailing requirement. Why do
> you think that Modulus of Elasticity is NOT comfortable in the histo
> presto vernacular? If I can start fooling Nick Micros into thinking
> I'm from the old country by sprinkling "heritage conservation" in a
> text then I think we can learn to use a few more terms. Why is
> "Modulus of Elasticity" more appropriate to use than "flexible"? I
> assume the modulus of elasticity is less with lime mortar than it is
> with urethane sealant.
>
> ][<en
------- End of Original Message -------

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