Monthly Archives: February 2009

Concrete vs Brick: What Difference Does it Make?

Concrete and clay brick are two widely used construction materials with a long history. Bricks have been made and used in the Middle East since at least 4000 BCE (Simmons 149). Concrete, a comparatively newer material, was first developed by the Romans in the 1st Century BCE (Simmons 67). Both saw incredible technical improvements in the 19th and 20th centuries such as the introduction of steel reinforcement and the formulation of high strength cements and mortar. Brick and concrete continue to be used throughout the world. Because they are suitable for many of the same applications, engineers and architects need to be knowledgeable about their respective strengths.

One of the most important attributes of a material is its overall environmental impact. Concrete and brick each consume large amounts of energy and potable water during their manufacture. More energy and water is needed at construction time, as is wood. The amounts of these resources differ in scale, however.

The energy required to convert limestone into cement is many times higher than that required to fire clay into brick. In most cases the electricity is generated by processes which release carbon dioxide (the most significant green house gas) into the air. By many estimates, the concrete industry currently produces around fire percent of the worlds carbon dioxide emissions (“Cement Makers Heed Environmental Concerns”).

Concrete also consumes much more water. Water is used to process the raw limestone. It is mixed with cement and aggregate to form concrete. It is also used to wash out trucks and to keep concrete slabs moist while they are are curing. In most cases, only fresh, drinkable water is suitable. There is an old adage in the building trade: “Don’t put water in your concrete unless it’s safe to drink.” Of course brick also requires water, but the amounts are far smaller than those for concrete. Its main use during production is to moisten the clay so it can be molded more easily. Some water is also used to make the mortar to hold the brick together. The volume of mortar in a brick wall is much smaller than that of concrete in a concrete wall. Mortars are also mixed with a smaller percentage of water than concretes because they are meant to be scooped with a trowel rather than poured or pumped into forms.

Another resource, consumed at construction time, is wood. Both materials use wood to build “centering”, which is a secondary structure that holds up arches, lintels, and floors until they have cured enough to support their own weight. After removal, this wood is often retrieved and used on other jobs. For concrete, however, wood is also used to build forms. Every column, wall, and slab is formed from plywood with timber bracing. Wooden forms degrade rapidly and can only be used a few times. After the cement soaks in they are useless. They will not even burn as firewood. Generally, they go straight to the landfill. Reusable metal forms are becoming more popular, but they are really only useful for standardized shapes. Special and “one-off” structures are still formed with wood.

Brick and concrete structures can both last for hundreds of years with proper maintenance. At some point, however, they will all become functionally obsolete and need to be demolished. Recycling programs are common practice throughout the construction industry. In the case of bricks (or any masonry), recycling is easy and requires little technology. Bricks are simply pulled off the building, hosed off, and sold for use in a new project. “Quarrying” old masonry structures for their bricks or blocks is a practice that goes back thousands of years. Many medieval and renaissance structures contain bricks and stones which were originally removed from Roman buildings. Damaged bricks can be crushed and recycled. They can even be safely buried since their principle materials, clay and shale, are completely inert and are already among the most common components of the Earth’s soils (“Building Green” 34).

Concrete is much harder to recycle. Removing the reinforcing steel and coarse aggregate (i.e. large rocks) from old concrete requires specialized heavy equipment and is an expensive and aggravating process at best. Once the concrete is isolated it is of dubious value. The best use for it that the concrete industry has yet discovered is to crush it into gravel-sized particles called “base”. This base can be spread under roads and concrete slabs to aid drainage. Unfortunately, the specifications for many government and private jobs explicitly forbid the use of crushed concrete base. Thus, the demand is currently quite small in relation to the supply.

Concrete consumes the greatest quantity of nonrenewable materials of any construction material (Simmons 66). Its terrible environmental impact is offset only by its longevity. Brick, also a long lasting material, is one of the most sustainable of building materials. Obviously, brick is a superior choice in many instances. In some cases, however, brick simply can not do the things that concrete can.

Reinforced concrete can be cantilevered. It can be used to make flat floor and roof slabs without the supporting vaults or arches which brick requires. Even the ubiquitous concrete parking structure would simply not work if designed with brick. Concrete bridges have reached spans which are surpassed only by structural steel. In contrast, brick buildings are generally limited by code to three or four stories. No large brick bridges have been built for centuries because the span between columns is severely limited.

Brick structural elements could never be made thin enough for the the sweeping roof lines and graceful thin-shell structures of post modern architecture. Nor does any masonry have the tensile strength that such designs require. Even utilitarian buildings like warehouses and factories often have tall, thin walls that would require buttresses or other supports if they were made from brick masonry. On the other hand, previous generations found brick to be quite adequate for everything from cathedrals to warehouses. Concrete became popular among architects mainly because of its low cost. Today the industry realizes that the “in place” cost of a material can be a small portion of its total “cradle-to-cradle” cost, which includes such items as damage to the environment, expenditure of resources, and cost to dispose of the material. When subjected to more modern cost analysis, concrete does not seem cheap at all.

Brick is a traditional, versatile, green material. Sustainable brick should always be chosen over unsustainable concrete when possible. Concrete is only preferable in highly engineered designs which require its greater strength. In such instances the design itself might well be questioned. In some cases, a simpler brick structure might serve as well, without the heavy resource cost.

Works Cited

“Building Green.” Ceramic Industry. 158.8 (2008): 34-35. Master File Premier. EBSCOHost. Orange County Library., La Habra, CA. 10 February 2009. .

“Cement Makers Heed Environmental Concerns.” Builders’ Merchants’ Journal. Oct. 2006: 38. Master File Premier. EBSCOHost. Orange County Library., La Habra, CA. 10 February 2009. .

Simmons, Leslie. Olin’s Construction Principles, Materials, and Methods. 8th ed. Hoboken: John Wiley & Sons. 2007.

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Quiz Night

When we think of librarians, we often visualize a prim old woman behind a reference desk who shushes us when we try to talk. I myself have often fallen victim to this stereotype even though I have been dating one of them for over a year. My girlfriend Danica scarcely fits this picture. She was a professional actress and circus performer before entering UCLA to study Library Science. Still, I had always assumed that she was an atypical member of the profession. The other night, however, I attended “Library Student Quiz Night” at UCLA. It challenged my assumptions about librarians.

As we approached the building we could hear loud rock music from inside and see flashing lights through the windows. Passing through the front door we saw a small table with name tags and felt markers. We wrote our names and attempted to unstick the tags.

“So far, getting the name tags unstuck has been the hardest part of the night. Hi, I’m Lindsey.” I looked up to see a youngish woman in a low-cut party dress. I knew Lindsey by reputation because she often does group assignments with my Danica. She had volunteered to organize the night’s festivities.

It took several tries to release the recalcitrant name tags. “I got them at Office Max. I think they’re really old,” explained our hostess. Once we had properly identified ourselves, Lindsey led us on a tour of the party.

First, we entered a university classroom. “This is where we have all of our classes,” Danica explained. It looks much like any university classroom with its rows of tables, white-board, and computerized podium. A bookshelf along the long wall was packed with reference books. I recognized the Encyclopædia Britannica among the rest by its brown covers. Basically, the room appeared exactly as I would expect a Library Science classroom to look.

Tonight, however, it had been decorated. Fancy red tablecloths with Chinese characters and tassels covered every tables. A table in front nearly overflowed with tissue wrapped prizes surrounding an immense trophy in the shape of a human brain.

The glorious brain trophy was at lease eighteen inches from hemisphere to paper-mâché hemisphere. It glistened with gold spray paint. Its base stood blank, ready to receive the names of the winning Quiz Night team.

Incongruously, a substantial pile of lacquered chopsticks rested to one side in fancy silk cases. Later, I learned that decorations and chopsticks were left over from Lindsey’s wedding.

As the tour continued we passed another classroom where young librarians played a “Rock Star” video game on a big-screen TV. Clearly, this was the source of the music we heard on our way in. They looked so young. Even though I knew they were all at least graduate students, most of them barely appeared old enough to be in college. The majority had made some effort to dress up for the party, but clearly there had been no coordination. I saw cocktail dresses, sport coats, tight “Emo” style jeans, and one young woman who would have been more suitable dressed to go square dancing than for a party in Westwood.

The last room we visited was the student lounge. I commented that it was one of the biggest, nicest I have ever seen. My girlfriend replied that it was not that nice; most of the furniture is from the 1980’s. Clearly, she has never seen our old engineering lounge at the University of Idaho, where the furniture looks like it is from the 1880’s.

This lounge was well supplied with crackers, cheese, and the usual party foods. Another table was covered in various alcoholic drinks. Like many graduate schools, UCLA’s Library school is a “wet” building. Avoiding a bottle of Boon’s Farm and a case of cheap beer, I poured myself a paper cup of generic-brand Merlot from a bottle with a plain black and white label. The first sip revealed it as far too sticky-sweet for a Merlot. It had that undefinable aftertaste which means a wine will produce a horrible hangover. The lady next to me chose the Boon’s Farm. “Ick! It’s greasy.” She filled another cup.

I was positioning myself to advance on the cheese table when a young woman in dramatic tortoise-shell glasses appeared at the door holding a megaphone. “Attention, attention. Quiz night will begin in five minutes. Everyone move to the other room and form teams.”

I snagged another cup of bad wine and shuffled down the hallway. As we entered, some of Danica’s friends waved to her. They had saved us spots on their team. Quickly, we huddled and tried to come up with a team name. The “Library Lions” was rejected as too cliché. They decided on “Team Bingo”. “Why Bingo?” I asked. “He’s Bingo.” They pointed at the man sitting across from me. “He’s our ringer.”

It turned out that Bingo (who’s real name is not Bingo) had actually been on Jeopardy a couple of years before. Getting him on our team was a real coup.

A young man with wild bleached-blond hair and a teeshirt that had been printed to look like an evening jacket was introduced as our moderator and competition began. He asked each question three times in a dramatic voice. We wrote the answer on a piece of paper. Discussion was allowed, but we had to keep our voices down so the other teams would not steal our answers. The questions were obscure. Many of them seemed drawn from the pop culture section of some out of print edition of trivial pursuit. Others were library oriented: “Which of these is not an official library of congress subject heading:. ‘Domestic Ass Industry’ or ‘Jello shots'”

At the end of the third round there was a break while teams passed in our first sheet of answers. The girl who had used the megaphone earlier leaped to her feet. “OK, so who wants a librarian tattoo?” one hand she clutched a packet of temporary tattoos with librarian-related themes, in the other a damp rag. The first one I saw had “Dewey” in the center of a heart. Librarians immediately began rolling up their sleeves.

Things did not look good as the scores were announced. Our team, Team Bingo, was in fourth place which was second from last. A team called the “Cobras” was in the lead. We had only three more rounds in which to redeem ourselves. To bolster our morale we began a chant “B – I – N – G – O, B – I – N – G – O, and Bingo was his name-o!”

“Looks like the beer is starting to kick in,” observed the announcer dryly. Glancing around, I realized that he had a point. One nearby contestant had six empty cans in front of him. “I think I need to go to the bathroom,” he muttered and walked off with exaggerated caution. We did not see him again.

Still, if the alcohol was affecting my team’s performance, it was hitting the others even harder. By the time the scores were again tallied, we had shot up to second place. The Cobras still won, of course. They had the honor of signing their names to gold foil seals which were affixed to the base of the brain trophy. It now sits in the student lounge, dominating it with its benevolent golden presence.

As the party broke up and the guests filed out with camaraderie and good will, I heard Lindsey say, “Everyone remember to take some chopsticks.”

I had fun that night. I also realized that librarians might by a little nerdy, but they really know how to party if you give them a chance.

 

Big Jobs

Now and then as a project manager you get a “big job”–a job that is bigger, faster, or higher profile than anything you have ever done before. When you actually get the job you are overwhelmed at the size. It seems impossible to complete it on time. By the time you catch your breath the first emergencies have arisen. Somehow, you get through it. Usually, as soon as the job is done and you cash the check, something three times as bad comes along and the whole thing starts over again. You have to start somewhere, though.

In the winter of 2002, I was 23 and had just dropped out of engineering school to become an itinerant handyman. Officially I had been a contractor for almost three months but so far had done only small jobs for hourly pay. A couple for whom I had been doing odd jobs called up and asked for a price to repaint their entire two-story house and replace most of the siding and trim on the south side. I carefully typed a proposal on one of the school computers, my old estimating textbook in hand. The sticker price came to just over $5,000. My biggest invoice before then had been for less and $500. Timidly I dialed the clients to ask if I could meet with them that evening. My bid was well received. I later found that local painting contractors rarely painted two story houses for less than $10,000. We signed a contract on the spot. Although they wanted me to start right away, the weather in North Idaho was still too cold. I promised to return on the first clear day after May 5th.

The weeks passed quickly. I was already terrified of the job. Would I have enough equipment? Exterior painting requires a commercial pressure washer and an airless paint sprayer–each with enough hose to reach the upper stories. After many phone calls I decided to buy the pressure washer and rent the airless. I had already burned through half of my initial draw and I had not even bought the paint. I knew I did not have nearly enough ladders, but there was no money left to buy more. I began building ladders from scratch in my mother’s driveway.

Meanwhile, my girlfriend and I were evicted from our trailer. As May 5th approached we were staying in my mother’s garage in Kalispell–almost 300 miles from the job site. I had not figured any hotel budget in my estimate. I realized we would need to camp out of the truck for the duration of the job. We were experienced backpackers, so we were used to living rough. I was still only figuring four days for the job: one for prep and carpentry, two for painting, one for cleanup. Four days in a campground did not sound like much of a hardship.

As the sun set on May 4th we loaded my old work truck and rolled out into the reddening light. I had no employees yet, so I brought my unemployed girlfriend along to be my helper.
There is a special expectant feeling about driving through the night to a new job. It feels as if nothing exists in the world except a ton and a half of truck and tools flying through a tunnel of light to its inevitable goal. I have encountered the feeling many times since. On that night, however, it was new and especially strong.

Problems began almost as soon as we unloaded. The first step in painting a house is to blast off the dirt and loose paint with pressurized water, which dampens and swells the underlying boards. Then as they dry they shrink again, loosening the remaining paint. Unfortunately, my new commercial pressure washer was twice as powerful as any I had used before. When sprayed directly at siding, it was as likely to cut completely through the wood as to strip the paint. No matter how hard I tried, most of the sun-rotten plastic window screens were also blown to shreds. The temperature that morning was still less than 50ーF. By the time

I finished spraying the house I was soaked. I shivered uncontrollably as I surveyed the broken screens and cratered siding. I got in the truck and cranked up the heater while I drove to the hardware store.

It was after lunch on my first day before I had re-screened all of the windows and patched the siding with putty. My assistant was making slow progress indeed scraping and sanding. Professional house painters know tricks that she had not learned in veterinary school. By dusk the paint prep was less than a third done. I had not even begun to repair the rotten siding on the south side of the house.

As the sun crested the mountains on the second day I prepared to start the woodworking portion of the job. When the house had been built it had been clad with a type of fiberboard siding that was textured to look like boards. To save money the builder had omitted window trim on the back of the house. In the harsh northwestern winters, water had soon seeped in around the windows to rot the siding. It had become so soft that I could force a screwdriver completely through it with one hand.

I set out for the local lumberyard to find suitable replacement siding. It did not take long to discover that the product in question was no longer available. In fact, it had been recalled nearly five years previously. Nothing of similar appearance was available in town in my price range. I was sure I was seeing the last of my profit vanish.

There is, however, one thing that looks quite a bit like mock-board siding: real boards. I was in the middle of timber country and could get pine boards cheap. There were problems, however. Real 1×6 boards are both wider and thicker than their fake equivalent. They come from the mill with a smooth planed finish that looks very different from the “rustic” look on my siding. Still, it seemed like my best option. I bought a truckload of boards.
Ripping the the boards to width was easy with my power saw.

Resawing them to the appropriate thickness was much harder. The only saw on my truck that could penetrate the entire width of the boards was my old handsaw. It took two more twelve-hour days to saw the rest of the boards. The resulting surface was very uneven and had to be dressed with a hand plane.

Even after dressing my boards the the right dimensions, I had to figure out how to match the texture of the original siding. Luckily, I had learned from my earlier mishap with the pressure washer. A few blasts with the medium nozzle stripped away the softer parts of the wood, leaving as rustic a surface as one could desire. Before they were even dry, I had most of the new boards nailed up. By the end of the fourth day (when the job should have been done according to my original schedule) I had siding and window trim installed Most of the scraping and caulking was done. We were mentally and physically exhausted. We had yet to spray a drop of paint.

On the morning of day five I sent my girlfriend to pick up the paint and masking supplies while I finished the prep work. I had just finished when she arrived with tears in her eyes.

“What happened?”

“You know how the tailgate doesn’t always shut? It opened up on the road and dumped most of the paint. I didn’t know what to do so I just drove away.”

This was serious. Our initial draw was gone. What cash we had was barely enough to cover food and campground fees for the next few days. We needed money to buy paint or we could not finish the job.

At least we had plenty of tape and paper to mask off the house. Most of the primer had also been spared because it was farther from the tailgate. We went back to work. At lunch time we picked up the sprayer and began spraying the first coat of primer.
A couple hours later another client called. She had several damaged fences on her ranch that she needed fixed immediately. We could also make some money by mucking her stables. The amount would be enough to buy more paint and feed us for a few days. Working on the ranch meant leaving the job site. Luckily, the next day was Saturday. Residential contractors normally work at least six days a week, but my clients raised no objections when I told them we were taking the weekend off. They didn’t look worried yet about the job.

By Sunday afternoon we were tired and stank of manure. Then again, we had cash in our pockets. As we drove back to camp, the truck’s engine coughed and burst into flames. Somehow we managed to extinguish the fire and push the truck into a parking lot. Water got into the carburetor, so I had to take it apart and dry it by hand before the truck would move again. The truck died several more times on the way back to the campground but never again ignited.

We set off on foot the next day to finish our painting job. The campground was only about five miles from the job site. I borrowed a car from an old buddy to pick up the paint.
Compared to the previous tribulations, the actual painting went beautifully. By Wednesday afternoon my clients had the best looking house on their block. Neighbors asked me for my card. When I opened the envelope with my final payment, I found a $500 tip.

My first “big” job was done. It took more than twice the allotted time and far more money than I had expected. Even so, I came out of it with a new pressure washer and a small net profit. It was a success.

The day we left town I ran into some of my former classmates. They were on their way back from their own graduation ceremony. We chatted for a bit and I realized I did not envy them at all. Despite all of the stress, uncertainty and discomfort, I realized I had found the right life for me.

These days I work for another contractor. I manage commercial construction jobs for him that can cost more than a million dollars and employ dozens of skilled tradesmen. Every few months I get another “big job”. Each one has emergencies, tragedies, and moments when I do not think I can bring it in. When things get really bad, though, I think back to a certain house in Idaho and smile to myself.