Architects and engineers have developed numerous advances in building technology that have allowed for the construction of taller, stronger, brighter, safer structures. As a result, contemporary designers have taken these systems and utilized them to help create a modern language of our building stock. At the same time, the lifespan of buildings still falls back on the weakest link of their components. Today, this is often sealants and adhesives, or “goop”, that are used to prevent moisture and air infiltration. Buildings need to solve the goop problem if they are going to last as long as the older buildings they are sitting next to.
From homes to hospitals, just about every building built today has a goop component. Many people know one genus as “caulk”. The inherent pliability of sealants make them the weapon of choice for the tiny cracks and joints that nothing else can seem to fit in, often at the interface between material systems such as when tile meets a bathtub or undermount sinks meet a counter top. Goop traces the frame of the windows in your supermarket and the door saddle you cross over into work. It fills in the seams of the sidewalk. It is everywhere.
At this point, most of our standard construction methods count on goop materials despite their limited lifespans. At first, they usually perform well (assuming proper, careful installation). Their elasticity allows them to stretch as the materials they bridge expand and contract with changes in temperature. But over time, their quality degrades and replacement becomes imminent. The flexibility of the material fades, causing it to harden and eventually crack. We all know the sight of failing sealants, falling out of cracks and looking like stringy pieces of old chewing gum. How many times have you had to re-caulk a sink or shower? (And these are not even outside battling the elements)
The Goopy Details
Traditional sealants can have numerous toxic chemicals that are not great for your body. Common culprits can include formaldehyde, ethylene glycol, ammonia, ethyl acrylate, acetaldehyde, and acrylonitrile. A tube of “Phenoseal”, a common household caulking product, has a nice warning label that admits it has components known to cause cancer. Additionally, these products often off-gas over time, releasing Volatile Organic Compounds (VOCs) into the air inside and outside your home.
There are a number of products that claim to be greener alternatives, but a closer look at their ingredients often reveals they cannot avoid key ingredients needed for initial pliability and quick curing. Even if one could get a more sustainable option not immediately as hazardous, this is still a material that will take ages to biodegrade while it releases those chemicals into the earth. The plastic tube packaging these materials come in will never be recycled or upcycled (what’s the difference?) due to their levels of contamination and the fact that too much of the product sticks to the sides of the containers.
As of now, our use of goop is far from incremental. Sealants and adhesives had a $39.1 billion worldwide marketplace in 2009 according to an industry report by BCC research. The construction segment alone was valued at $4.8 billion in 2010 and is expected to increase to $6.2 billion by 2015. We are only strengthening a product line that creates some of the worst kind of waste and lots of it.
The Bigger They Are…
Re-caulking a tub is one thing, but there are entire buildings that depend on the integrity of their sealants in order to function properly and avoid water and air seeping through their skins. The rise of glass façade construction in pursuit of more light and views has hung its hat on the sealant joints. Window glazing is essentially goop that seals and bonds glass to its framing systems. Most manufacturers of curtain wall or window wall components will warrantee their products for somewhere around 40 years. To most residential consumers this sounds like a deal, but in the life of a large building 40 years doesn’t even get us halfway there.
Even a building like One Bryant Park, arguably one of the greenest skyscrapers in the world, is still wrapped in glass curtain wall with every panel counting on sealant for its waterproofing. What happens in 50 years when the second tallest building in New York City has to address its entire exterior wall? Given this construction method is still relatively new, no one really knows right now. A building that is to last for 100 years cannot hang in the balance of its caulk joints, especially if it towers hundreds of feet above the street.
Goop-Free Design?
Is it possible to minimize the amount of goop we use in our new buildings? Ironically a good place to start is not the future of buildings, but the ones that have already been built. Sealants were not always a go-to method for water-proofing our built environment and there are reasons that many of the historical forms we take as commonplace look the way that they do.
Many modern buildings take the appearance of tight, exterior skins stretched across a structural form beneath, causing the walls that face the elements to be very flat with all components in line. This only makes them more difficult to shore up against water. Recessing windows and other penetrations into a wall makes it more difficult for rain and snow to drip down the outside of a building and into its walls.
Pitched roofs are often views as “older” than flat counterparts, but they excel at taking water away from a building rather. There is no pooling on pitched roofs and no integrated roof drains. Furthermore, roofs that overhang the walls beneath them carry water farther from the walls and the foundation than those without them while shielding more of the walls and windows from precipitation.
Every exposed, exterior joint has to be addressed for weatherization, but having materials meet in the same plane complicates our ability to keep the water out. Joints that are formed by overlapping materials (like the clapboards on the side of homes) make water infiltration naturally more difficult without the use of goop. The goal of goopless architecture brings about a language of its own that more and more designers are beginning to explore.
Our current method of construction is limiting the integrity of our buildings from the start by relying on sealants as our first and main line of defense.
Photo Credits: refinishingpros.com , wlcaulk.com ,
October 20, 2010 at 2:02 pm
Glass curtain walls are environmentally friendly. A glass curtain wall is such a great way to let in light and make the inside a building much brighter. You don’t need to add a lot of so-called goop. If you want to add one to your home, I would recommend taking a look at McGraw Hill Sweets Directory of construction products and manufacturers. They offer a lot of great information and I love the CAD details that I can download from their site. While I do work for them, I honestly find that they offer really valuable information that makes my projects so much easier. I definitely recommend them.
October 20, 2010 at 3:15 pm
Kim,
Thanks for stopping by. I think architects acknowledge that curtain walls are a double-edged sword given that you are trading light and views for longevity and insulating quality. The more light you let in the less control you have over insulation. Even double-glazed systems have R-values that are a fraction of solid wall constructions, which means you are creating a thinner barrier for energy to permeate through (both ways). You have to worry more about heat gain unless you are implementing a thicker double-skin system with integrated shading (greatly increasing cost as well as the number of glazed joints) and heat loss becomes just as tricky.
The fact of the matter is that curtain wall systems require glazing joints that are a pliable, adhesive sealant. Doing one strip on your home is one thing that can be easily serviced, but a skyscraper of glass built today could require drastic maintenance 50 years from now–which requires more materials, more waste and more energy. That would mean that in comparison to say, a brick wall, it is not necessarily all that environmentally superior just because it gives you natural light. The wild card is that we just don’t know exactly how these walls will perform in the long term. The entire lifecycle of the system needs to be analyzed and considered when trying to make a sustainable solution.