The following, so well written, I had to share (with permission) for the benefit of others. It is a comment in reference to a Crain’s article on scaffolding in NYC and why there is so much of it.
By Edward C. Greenberg; NYC copyright and intellectual property litigator and teacher • 4 days ago
Without dancing on the head of a pin – would you agree that most buildings 130+ years old in NYC may have pre code electric, non-standard plumbing and mortar which is beyond its useful life UNLESS the building has been substantially re-habbed in the past?
NYC buildings which pre-date 1898 use non-standardized sizes/types of plumbing. Others which were electrified in the early 20th Century were not done up to code as no code existed at the time and would fail the standards of the codes now in effect..
Re-pointing is the reason for most scaffolds in NYC,
and repointing older masonry carries risks of permanent damage to the masonry units, if properly done it can restore the aesthetics of the façade and improve the weather resistance of the building.
The properties of the repointing mortar must be compatible with the existing masonry units and bedding mortar while still displaying reasonable durability. The mortar mix of a previous repair should not be replicated without an assessment – although this step is skipped quite often by contractors.
No single mortar mix fits all needs and the mix must be adapted to the masonry units hence the importance of exhaustive pre-design condition surveys and reviews – again a step often done in a slipshod manner for non-landmark or architecturally significant buildings.
Low-strength mortars are less forgiving of poor execution and curing than mortars used in modern masonry and this needs to be accounted for in every step of the process, from design and specification of the mix to quality control on site.
As you may know, there are buildings in the UK which have mortar hundreds of years old and in fine shape. Such cases are rare. There are no reliable figures for the useful life of mortar -especially in NYC – as the appropriateness of the mix employed, water leakage from other sources, quality of the existing brick or masonry, exposure to wind, condition of any structural rebar and whether the bricks have become porous and need replacing are all factors in whether the integrity of the mortar/brick/stucco will stand up for one year of one hundred years. Many UES buildings saw total brick replacements in the ’90s and early 2000’s – many had been constructed with glazed white brick.
Thus it is not whether the “buildings” have outlived their useful lives but rather whether the facades have. The cost of repairing a facade may or may not be justified given the condition of the building, value of the real estate it sits on and cost/time of repairs.
Yes, there are paving stones and bricks that last hundreds of years BUT given the age of some of these buildings already and the cost of repairs, a developer or prospective purchaser may be better off simply knocking the aged building down and starting fresh.
There are NO industry standards for the useful life of mortar as mixes vary as do the quality of applications as do the composition of the bricks or masonry to which they are applied.
I have litigated the point and the above was paraphrased expert testimony. Note that in hot, humid areas of America the expense of brick construction which is usually justified in the MidWest and Northeast, precludes its use. With no freeze/thaw cycles and high humidity, cheaper building materials are often more durable.
As I trust you know, repairing/re pointing brickwork on a NYC building is a very expensive and time consuming process. I can’t recall the last major hi rise commercial building built in Manhattan employing brick. My office @ 51st and Lex is in a land marked brick skyscraper. We are surrounded by buildings with skins of glass and metal.
Finally NYT 10/3/11: “Over the decades, white brick buildings — those wedding-cake-shape stalwarts of postwar living — have fallen out of favor and in again among residents, architects and preservationists. Now some of them are falling apart. Built in New York in the 1950s and ’60s, the buildings were part of the answer to the housing shortage touched off by returning veterans of World War II; the white glazed brick was supposed to make them look like beacons of clean, shiny modernism in the midst of the dirty city.
“Going back to the Woodstock era and the Age of Aquarius, an architect came up with this idea of a self-cleaning building where the rain would wash down this slick glazed brick and clean the facades,” said Howard L. Zimmerman, an architect with experience in restoring white brick. In addition, the glazed bricks were supposed to keep the inner walls dry, repelling the moisture as it slid down the face.
“But things have not quite worked out that way. Water inevitably seeped in — whether through the porous mortar joints between every brick or from behind — and became trapped, prevented by the glaze from quickly evaporating. Then, with the freeze-and-thaw cycles of winter, the water would expand, putting pressure on the glaze, causing cracks and overall deterioration.
“This was actually a ploy to make the buildings quote-unquote more waterproof, and it’s backfired big time,” said Jon Colatrella, the survey team leader at Rand Engineering and Architecture. “Once that moisture gets trapped in between those two materials, essentially it freezes over time and it just starts to spall and pop and crack that front face right off.”
“This pattern has plagued dozens of buildings in the city — some of them subject to landmark protection, like 900 Fifth Avenue, which replaced its facade about three years ago. And it threatens many more, like 2 Fifth Avenue, which has been struggling over a renovation now estimated at almost $31 million. That figure also includes other repairs and is resulting in an assessment of $125 per share, or $100,000 on average, from its shareholders”
So the “useful life” of these pricey facades was just 50 years.