Old building materials, new insulation standards and consistently wet summers can spell trouble for many of Boston's historic homes, contractors and experts said, so property owners need to be on the lookout now for warning signs.
Neighborhoods like the Back Bay, Beacon Hill and South End are known for historic brownstones and rowhouses, but buildings from a century ago weren't constructed according to current codes.
In
particular, lintels which support walls above doors and windows, may
have been made with steel, but what was state-ofthe-art then is woefully
out of date now, according to John Holland of Holland & Co who has
decades of construction and rehab experience.
"When
steel lintels were introduced in the turn of the century, they were new
material, but they weren't galvanized," Holland said, noting that kind
of metal is susceptible to rust and water damage, and that can lead to
significant repairs as water freezes and expands over time, damaging
stone, and lintels.
Rusting
lintels can expand and crack the mortar work around them, leading to
issues with the wall itself, Holland said. And the lintels’ L shape
extending into the brickwork means replacing them is no easy task
either.
"They have to
be replaced and that's difficult as the lintel is buried in the masonry,
so you have to take out the masonry," Holland said.
Chris
Paszko, director of Building Envelope Sciences at Gorman Richardson
Lewis Architects, said that even if brownstones may not have galvanized
steel lintels, the material can be present elsewhere in the structures.
"A
lot of brownstones tend to keep doors and windows more narrow. Instead
of steel they'd use stone. But it wouldn't necessarily just be lintels,
it could be in supporting pieces in other parts of the building," Paszko
said.
Real estate
developer and property manager Robert Weintraub of Premiere Property
Solutions said steel lintels are more likely to be found in older
buildings with larger windows, particularly those taller than 70 feet.
Under
city ordinance, those buildings must be inspected every five years for
facade problems. But this summer has brought major strain to structures
across the city, he said.
"The
overall building envelope [in Boston] has sustained substantial tests
this past summer, like horizontal rain and torrential downpours. Roofers
and maintenance workers haven't caught up yet. There have been very few
dry days," Weintraub said.
And
the solid mass masonry of older buildings, relying on several layers of
bricks, can see further moisture problems if they're improperly
insulated, Holland said. The city's old brownstones were built to absorb
water and dry out in tune with natural cycles, and adding insulation
can disrupt that setup, he said.
"Those
freeze/thaw cycles are particularly deadly for solid mass masonry
buildings, and if you put insulation in you could be worse off," Holland
said.
"You're asking
the building and the walls to do something they were never designed to
do originally. They were more aligned with ambient temperature and
conditions. Now the AC is blasting 70 when it's 90 out, that's putting
the wall under stress," Paszko said.
Both
Holland and Paszko said property owners need to routinely inspect their
buildings for exterior damage to masonry work and lintels, with lintel
warning signs including rust bleeding through sealant joints, and rust
jacking at lintel borders and window corners. While the repair work is
expensive, it's more expensive to delay it, Paszko said.
"You
might see an issue that raises concern and dismiss it because you think
it's not a big issue, but it's important to get someone to help make
that decision for you. And that you're not making the wrong repairs that
can do more harm than good," Paszko said, adding that repatching is
only a temporary solution for lintels.
"You don't want to repatch. You're covering the symptom of the issue. Don't address the symptom. Address the cause."
