[log in to unmask] wrote:

> But >>what do you add to mortar to make it sandy beige?   
> Whatever it was, the "waterproofing company" which worked on 915 West 
> End Avenue (1922, Rosario Candela) decided to save it for something else.

c,

Are you suggesting that the current mortar is too white? Or that it is 
not subtle whatever the color?

First ingredient... one needs to care what color the mortar was, is and 
will be to begin with.
2nd ingredient... one needs to have a clue how to adjust for colors 
(this may also presume some ideas as to ingredients & proportions).
3rd ingredient... it helps if one is sensitive to the subtle differences 
between one mortar and another.

General rule of thumb is that one try to match the color of the original 
aggregate, to let the aggregate provide the primary color as it will be 
more enduring with weathering. So in this case a Long Island sand is a 
typical sandy beige. Avoid tints where possible, unless the original is 
a tinted mortar, and when using tints use mineral (not organic) tints. 
More exotic approach would be to determine the color of the original 
aggregate and the matrix (cement/tint) to come up with a very subtle 
mortar mix, particularly when weathered (patinated) say a dark coffee 
brown aggregate (Brooklyn Greenpoint Shipyards variety) with Rosendale 
natural cement with a hint of red tint.

We were doing a repoint job on the Episcopal Church of Ascension in 
Brooklyn, near to where the Monitor was built, and we had to go to great 
lengths to match the aggregate. Purchasing it in NJ by the bag. Note: 
most sand in Manhattan repoint jobs comes by the bag. Along during the 
project we had to do some work to re-route the site drainage and on 
digging a hole in the areaway found tons of the really nice sand that we 
were paying mucho bucks per pound for, plus time & cost of driver to go 
to NJ to get same. Lesson learned? Consider the history of the site and 
be prepared to dig a hole to look for sand for the mortar (Occam's Razor 
once again). But, of course, this is where you have a situation that 
accepts the First Ingredient above.

][<en

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