View From Above
by Michael S. Teller, A.I.A., NCARB, LEED AP, Principal
Any analysis of an existing building must include a review of all building elements from above the building. More than once, we have found severe deficiencies in critical building elements by simply looking from a different vantage point.
Many times, by viewing these elements from street-level the full extent of deterioration cannot be observed because the deterioration begins on the upper side of the element. Therefore, viewing the building façade from a boom lift or swing staging (even as easy as looking over the edge of the roof) can give a better view, certainly a more accurate view of the full extent of deterioration, and in some cases hazardous conditions.
We’ve observed many times building elements that were on the verge of falling that could not be seen from the ground.
In the Northeast, with severe winter weather, water collects on horizontal surfaces such as cornices, parapets and shelves made of various building materials and becomes absorbed into the system. Gradually this causes deterioration through the “freeze/thaw” process, which occurs when water (even at a micro level) trapped within a solid element, such as brick or concrete, freezes. Water expands when it freezes causing pressure on the surrounding substrate. Then it meets and the pressure is relieved. After enough of these cycles, cracks begin to appear as the parent material weakens. Eventually these gaps grow into cracks big enough to allow more water into the system and the “freeze/thaw” cycle accelerates. Eventually the pressure causes even more significant deterioration and mortar, for example between stones or brick, weakens and washes away during a larger rain event. Over the span of 20+ years, entire mortar joints can disappear leaving the joint open and the building façade extremely vulnerable to weather and infiltration of additional moisture, which causes greater damage.
This photo is from the top of the chimney on a historic Cape Cod structure. At some point in the building’s 120 year lifespan, additional bronze bars were installed to reinforce and likely anchor chimney cap stones in place. In one chimney the bars were intact but in the second chimney the bars were missing. Once we accessed this area, in person up close, we observed that the mortar was completely missing and that, in some areas, the bars were no longer present. This resulted in a hazardous condition where any severe storm could have potentially dislodged large pieces of masonry to fall below.
The City of Boston and other major municipalities throughout the north have instituted “high-rise inspection” ordinances which require buildings over 70 feet tall to be inspected in this manner every five years. The law was prompted by numerous instances of bricks falling off the sides of buildings onto busy sidewalks below in major metropolitan cities such as New York and Chicago.
Unfortunately, in these tough economic times, funding for yearly maintenance of building exteriors is not being expended and deterioration continues. However, many building owners believe, incorrectly, that masonry, stone and concrete buildings require no maintenance. While maintenance cycles are longer for these construction types, it is still required. Have someone observe your building from above to determine if there are any hidden liability issues that need to be addressed.
If you would like us to examine your building, learn more, or discuss a current or future project with us, please contact:
250 Dorchester Avenue
Boston, MA 02127