In my opinion retooling to sound watershedding stone is the first, then
dutchman that can be "hung" on pins with mortar (closely matching the
characteristics of the b-stone) used as pin and patching grouting (not
adhesive). The dutchmans need to be deep enough to be structurally sound and
well bedded in pointing mortar.

Patching compounds are "relatively" temporary. My experience is with Jahn
and Edison. My first b-stone repair job was late 1980's with Edison. The
patches are all still in good condition with maybe a bit of fading but they
have all held well and not damaged the adjacent stone. I live in Greenwich
Village and many houses have been "re-brownstoned" (Landmarks term) by
scarifying the entire facade and then brown stuccoing. Some work okay and
some fail soon after installation. Either way, the houses look like what
they are - brown cement boxes missing the rich patina of age of a natural
material.

As with all this that we do, craftsmanship is the most important and most
difficult to achieve. We specifiers should be able to decide on the correct
material if we spend time but the crafts-person's work in preparation and
application is paramount.

Eric Hammarberg
Associate Director of Preservation
Associate
LZA Technology
641 Avenue of the Americas
New York, NY 10011-2014
Telephone: 212.741.1300 extension: 1016
Mobile: 917.439.3537
Fax: 212.989.2040
email:  [log in to unmask]


-----Original Message-----
From: Ralph Walter [mailto:[log in to unmask]]
Sent: Thursday, November 01, 2001 7:20 AM
To: [log in to unmask]
Subject: Re: sandstone and epoxy and patching mortar


david and Michael,

Thank you both for the lowdown on epoxy patching of this vile material.
What
are your views (and those of our esteemed colleagues) on use of patching
mortars?  I am working on a brownstone church (c. 1850, rebuilt after fire
c.
1895) with a fair amount of delaminating/melting stone.  It has had some
Jahn
patching but I am concerned that the only real way to do the job right is to
cut back the bad stone and install dutchmen (4" deeep or so).  Am I right in
thinking the mortar patching is at best a temporary (and if so, for how
long?) solution here in fabulous NYC, or... am I full of shit?

Thanks.

Ralph