On 3/23/2010 7:02 PM, Judith E. Selwyn wrote:
Good
mortar costs more.
Equating cost with efflorescence works for me.
Masonry done when ambient temperature is below 40 degrees IMHO always
tends to have the mortar effloresce. Chemistry of the mortar mix is
relevant, a more carefully designed mortar will cost more, with
cold-weather additives (generally forbotten in histo presto) or use of
non-staining white Portland (rather than a bagged Type-N masonry
cement)... but also the cost in labor/materials/energy to provide a
properly heated environment for the mortar to cure in an appropriate
manner. All sorts of variables, each one of them associated with a cost
come together, including the desire to match the appearance of the
existing mortar.
Then, as remarked elsewhere here on BP, water... lack of understanding
of masonry and how it interrelates with water (and it always and will
forever interrelate with water) ends with poor waterproof (waterproof
being a misnomer as it is more like water-control) detailing. In answer
to Leland's question as to why so much contemporary/new-built work
effloresces... because the detailing of water-control is no longer done
with any intelligence, it is certainly NOT done by many architects...
which becomes immediately evident when you investigate a new-built
building for water problems (particularly at roof lines behind raised
parapets) and trace it back to the construction documents and find that
the architectural drawings used for the build did not detail the
flashings. My surmise as to why they do not detail the flashings is
that 1. they do not understand either masonry or water and 2. that
despite their lack of understanding they want to avoid the risk of
being responsible for the design, and the failure, so they push the
responsibility of design onto the trades... and in roofing in
particular where water penetration very often leads to litigation. IMHO.
Someone recently expressed to me the 'greater fool theory'... there
always is a greater fool further down the line. Thus it goes with
cost... if the work is driven by cost then there is always the greater
fool down the line who will offer a lower cost. That fool may be the
less expensive, and less responsible architect, and on down the line to
the less intelligent and less expensive mason and the least expensive
materials.
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