Dear Tim: I have
asked you for advice in the past and it was dead on - so I thought I would try you
again. I am building a new home in Chicago. The problem is the timing might
require brick work to be done in the winter months. I have seen this done at job
sites around Chicago and all seems well. Some guys use tarps and heaters when
applying the mortar and probably add some type of additive for the mix -- is this
an acceptable practice? Is its skill dependent on the brick laying team?
Finally, if I were to see failure in the mortar due to the weather, do you think
it would occur within a year or something that would gradually occur and not
become a significant problem for a few years? Maury P.
Dear Maury: Brick can be installed in cold weather but there
are very strict guidelines as to how it should be done. The biggest problem is
that the water in the mortar mix can freeze before it has a chance to develop
into hard crystals that interlock the sand, cement paste and brick into one homogeneous unit.
There are additives you can blend in with the mortar
mix to work at or slightly below freezing temperatures. These additives are very
effective when used exactly as directed on the product labels. Problems happen
when the masons stray from the temperature ranges that are suggested by the
manufacturers.
Another trick real craftsmen use is to warm up every
component used in the process. With proper planning, a tent can be built over
all of the materials and the brick, sand, sacks of mortar and water are heated
so they think it is 60 F or higher outdoors. Raising the temperature of all of
the materials is very effective and can make all of the difference.
The
best solution is to tent the entire house and create an artificial environment
where the entire house and all of the materials think it is 45 - 55 F. This
enclosure will be expensive to build and maintain, but if you leave it up for
three days after the last brick is installed, you should never have
problems.
If the mortar does freeze, failure will be immediately visible.
The mortar will fall apart with little effort after seven days.
