I agree with Michael especially in taking guidance from (but not blindly following) good lab analysis of both the outer possibly pointing mortar and inner bedding mortar (I don't know much about the use history of natural cement). I would also suggest trying to find protected areas of pointing mortar such as immediately below a cornice, a window reveal or behind shutters to verify the original un-weathered pointing mortar. Eric Hammarberg Director of Preservation Vice President Thornton-Tomasetti Group LZA Technology Division 641 Avenue of the Americas New York, NY 10011 Telephone: 917.661.8160 Fax: 917.661.8161 Mobile: 917.439.3537 email: [log in to unmask] -----Original Message----- From: edison [mailto:[log in to unmask]] Sent: Tuesday, November 29, 2005 7:58 AM To: [log in to unmask] Subject: Re: [BP] technical question Ralph, Given the age of the building, there is an excellent chance that the original mortar is a natural cement/lime blend. A higher lime content could have been used for the setting mortar, a higher cement content for the pointing, common practice for the period as cement was costlier than lime but lime was considered deficient in weather resistance. I would send samples of each to a lab that has experience in distinguishing between the various binders in use during the 1890's and let the results guide me. If they determine that there is natural cement then the buff color is the cement color and original to the building. Edison Coatings, Inc. Michael 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: [log in to unmask] To: [log in to unmask] Sent: Tue, 29 Nov 2005 06:59:24 EST Subject: Re: [BP] technical question > It's time to put on your conical thimking caps, boys and girls. > > Our fearless leader ][<en and I have been working on (the design phase > of) a project here in Summit, during the course of which the local > Town Hall, an 1892 buff(ish) to salmon-colored, pressed-brick > building, will have its butter joints repointed. The original mortar, > when brick are removed, looks very light colored (I would describe > it as very pale yellow, or a slightly yellowish white); the mortar > visible at the faces of the joints has a buff-ish color much closer > to that of the brick. We didn't see any sign that the buff mortar > was part of an original pointing job, or part of a repointing, either. > > Early (pre-1900) photos show the facade without apparent contrast between > brick and mortar color, which is what makes me doubt that the pale yellow > mortar was ever exposed to sight, but nevertheless the pale yellow is > what we find. The surviving mortar joints, 113 years later, are only > slightly recessed from the face of the brick, so the lack of contrast > between brick and mortar can't be blamed on the mortar being darkened > by shadow lines cast by the brick.. > > Anybody got any guidance for me on how to choose between mortar that looks > too light,as opposed to mortar that doesn't match the (interior) > sample but looks right? I am scared to death to call for the pale > yellow mortar and have the building wind up looking like there are > neon lights in the mortar joints, but that seems to be what the > mortar samples show. > > Thanks. > > Ralph ------- End of Original Message ------- -- To terminate puerile preservation prattling among pals and the uncoffee-ed, or to change your settings, go to: <http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html> <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> The information in this email and any attachments may contain confidential information that is intended solely for the attention and use of the named addressee(s). This message or any part thereof must not be disclosed, copied, distributed or retained by any person without authorization from the addressee. If you are not the intended addressee, please notify the sender immediately, and delete this message. <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> -- To terminate puerile preservation prattling among pals and the uncoffee-ed, or to change your settings, go to: <http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html>