Mike,

You mention using latex additives in situations of high moisture exposure,
what about the reverse- moisture release?
I didn't know you were doing the lime thing?  Tell us more?

Best,

Leland
-----Original Message-----
From: Michael P. Edison <[log in to unmask]>
To: [log in to unmask]
<[log in to unmask]>
Date: Wednesday, August 05, 1998 2:05 AM
Subject: Latex Additives


Message text written by Ken-- "BP - His DNA is this long."
>I've always been told not to use latex additives in brick mortar but I do
not
know why. I realize that latex additives are used in new construction, but
I
never do new construction. I know enough to never suggest using a latex
additive and let the design professional make the first move. But the whole
thing is a mystery to me.

Could someone please explain the pro/con of the latex additive taboo?

][<en Follett
<

I was sort of hoping someone else would start this one off, but I'm a
sucker for this sort of bait, I guess. So as a manufacturer and proponent
of latex-modified mortars, you probably expect me to deliver the PRO side
of the issue. But actually,when it comes to repointing mortars, we rarely
recommend latex-modified mortar and routinely formulate customized
lime-cement mortars.

Lime-cement mortars (or for those situations where it is warranted, high
lime mortars) have excellent bond strength and low modulus and do a
wonderful job without the appreciably higher cost of latex modification. So
where DO we use latex? Special situations involving difficult-to-bond
surfaces, because adhesion is improved. Also I have also seen them used on
masonry subject to higher moisture exposure, such as non-vertical wall
sections below long vertical runs.

Of course, latex or non-latex is not the only issue. This is not always a
black or white question. Rather, there is a continuum of choices, with
polymer:cementitious materials ratios ranging from zero (no latex) to as
high as 0.5 or more. (For repair mortars the optimum levels are usually
between 0.1 and 0.2).

Mike E.