Milwaukee’s Central Library gets a green roof

As part of the Milwaukee Metropolitan Sewerage District’s (MMSD) efforts to encourage the creation of green roofs to slow down the flow of storm water into the sewer system, the roof of Milwaukee’s Central Library has been planted with sedum, chive, and ornamental grasses on top of a six inch layer of gravel and soil. The roof, which totals 30,000 square feet -or nearly seven-tenths of an acre – will collect and store thousands of gallons of rainwater during a downpour, rather than allowing the clean water to drain immediately to a street sewer, where it could contribute to a sewer overflow.

Combined sanitary and storm sewers on Wisconsin Ave. in front of the library quickly fill with rain in a deluge and begin spilling into the district’s deep tunnels. Pipes draining street sewers into the tunnels are closed as the underground caverns fill, causing street sewers to overflow to local rivers and Lake Michigan.

Green roofs can become saturated after hours of heavy rainfall, and additional rain would slowly begin to drain to a street sewer. But that delay in draining to a sewer buys time for the district’s system of tunnels and sewage plants to treat earlier flows.

According to Taj Schoening, business operations manager for the Milwaukee Public Library, an added benefit for taxpayers is the durability of the library’s green roof. “This will double the life expectancy of our flat roof,” she said. “We won’t have to do this again for 40 years.”

The Central Library’s green roof, which will open to the public in June, was paid for through a $250,000 grant from MMSD, along with $950,000 in funding from the city, which also contributed $100,000 for solar energy panels.

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18 thoughts on “Milwaukee’s Central Library gets a green roof

  1. I like how they omitted probably the biggest question: How much would a regular roof cost? Using this website(http://www.coolflatroof.com/roofing-price-calculator.php) and punching in the square footage and making it the most difficult roof to produce, you come up with about $300,000(east coast prices, btw). So the roof is twice as durable, but 4-5 times more expensive. So cost savings are out the window, especially since this is to be done every 40 years at the taxpayers expense.

    They also don’t mention the amount of water that would be temporarily held back from the sewer system. Using the area of the roof(30k sq. ft.) divided into the area of Milwaukee(2.7 billion sq ft), your looking at about 0.001% of water being held back assuming uniform rainfall over all of Milwaukee.

    Bottom line – waste of 1.2 million.

    1. You’re right. We should never do anything to beautify the city, its buildings, or our environment. Pinching every penny until it’s blue in the face is vital. Especially without knowing what we’re talking about.

    2. @squidknukle – You assume all rain from Milwaukee flows into rivers or sewers. Do yourself a favor when looking up your info – look up the definition of impervious surface. Then recalculate. Then figure the cost of each CSO. Every building counts towards CSO just like roads and parking lots, and you have to start reducing impervious space somewhere. Good for your state for setting an example that you’re too bull headed to notice because its wasting YOUR tax dollars. Definitely an ineffective expense, one that no private industry would spend on their own building… What’s that, green roofs ARE on private buildings? Surely you’d have allocated the money better though – that’s why you’re in public service right?

  2. Yes, because the definition of beautification is some shrubbery on top of a library that noone can see unless in a helicopter or a nearby taller building.

    Waste of money.

    1. Hardly. Do you understand that this aides storm water retention, thus lowering the amount of money used by the public water system? It lowers the ambient heat in that area of the city during the summer, thus lowering the amount of money used by the public library and will help lower the amount of money spent on emergency services used to aid people suffering heatstroke or exposure. It saves money in the long run. That’s not a waste of money.

    2. You must have missed the part about how the roof will be open to the public, so plenty of folks will get a chance to see the roof up close and personal.

  3. And what the silly squid doesn’t mention (or was too lazy to figure out) is that the grants from MMSD and Focus on Energy don’t happen without the green elements on there, so the extra up-front cost to City taxpayers for making the roof green is minimal compared to the savings in both energy usage and stormwater runoff. It pays for itself in the operational savings.

    Then you realize that the longer life means that 2 roof replacements would be needed on a conventional roof vs. 1 for a green one in the next 60 years, and it’s a no-brainer.

  4. I didn’t miss the part about being open to the public. And when everyone has seen it once(except for me because I could care less), it’s pretty much served its beautification purpose.

    Jake, I can’t believe I have to spell this out. I could build 4 or 5 regular roofs for the price of this one green one. I put it right up there for you to look at yourself. The green roof would have to not be twice as durable, but 4 to 5 times more durable to make economic sense. And it’s not 60 years, it’s 40. Nobody will probably even go to that library in 40 years. So this no brainer you speak of exists only in your head.

    The stormwater runoff is negligible, it is one freaking rooftop in an entire city. And tell me how that saves money exactly? It’s not going to absorb all the water and even then it is only going to delay what it doesn’t. How does this save money? Oh, maybe it will save money by whoever has to tend to the roof garden. Nevermind, that costs money.

    1. Yes the amount of water on the library roof compared to the city’s overall runoff i negligible…yes in current dollars it may be more that equivalent convential roofs (how low would a flat membrane tar and gravel roof last in a downtown urban setting – anyone got any documentation)…and maybe the reduced cooling costs for the library won’t offset the marginal cost differential over a convential roof…but someone somewhere has to show the public and private sectors the efficacy of going green. And like all things new the per unit cost starts to decline as adoption of the product increases in the market place.

      And please don’t go to the library…I’d hate to have my tax dollars pay to clean up the place when your head explodes at the wonders inherent in a modern library.

    2. Squid…not to get too personal, but are you a CITY of Milwaukee resident?

      1. Yup, I live on the East Side.

        Look, I don’t have a problem with moving in the direction of green and efficiency but I want it done smartly where the return on investment is evident or else the purpose of moving in that direction is moot. My problem here was the tilt this journalist had on the story that made it sound like money well spent when in fact it wasn’t.

        1. Money well spent is in the eye of the beholder…depends on what your goal is…and obviously capping the library with the cheapest roof on the market isn’t the goal here.

  5. Silly Squiddy- I’ll just say you’re WAY off on your price estimates and on the durability of the Library building ($300,000 for a 35,000 sq.foot roof on an historic 111-year-old building? Show me that contract). The studies are all online on this roof project, as well as similar projects. READ THEM. Unlike SykesWorld, you are not entitled to your own facts on the costs of replacing that roof, and unlike WalkerWorld, the Barrett folks aren’t keen on letting buildings literally fall apart on their watch.

    We aren’t even bringing up how the educational presentations on this roof match perfectly with the goals of the library expanding learning. And in the real world, things like that make a difference in people’s lives. And I’m betting you don’t live in Milwaukee, which explains your childish stubborness about being proven dumb on this, and your lack of appreciation of such a landmark.

    1. They didn’t replace the roof! They threw up a membrane, some rock, soil, and planted. They didn’t tear into the shell of the building and replace supporting structures and then plant their garden. Instead, they put water-holding soil up there. I probably have good cause to question the durability of the roof with the addition of the extra water weight that is going to be up there.

      All I talked about was a replacement covering for the roof, because that is in fact what they did with their green one.

      And talk about making a difference in people’s lives. You’re telling me the best thing that 1.2 million dollars can buy to make a difference is a rooftop garden? Please, I don’t have to be a bleeding heart liberal to figure that one out.

  6. I really like what Jason Haas said,” You’re right. We should never do anything to beautify the city, its buildings, or our environment. Pinching every penny until it’s blue in the face is vital. Especially without knowing what we’re talking about.” There is a lot more to understand about the validity of green roofs, and the quality of life.

  7. Hi-
    I’ve been a commercial roofing contractor in this city for 30 yrs.
    Mr Squid has a very good point…
    As I read it, we have 30,000sq ft.
    An unbelievably expensive reroof on a job that size would be $10/sq ft., $300,000 ($150,000 is more in line). We seem to have paid
    about 4 times that. The much vaunted “green” roof at UWM last year was in the same stratospheric price range.
    Mr Jason, while probably well intended…ok, we’ll give him the benefit of a considerable doubt born of his “greener-than-thou” attitude.. misses the point by a mile by speaking from an uninformed position. It’s easy to overpay spectacularly (or to justify doing so) when it’s not your money. Just repeat platitudes.
    Question: Why does a water retention system need plants? How ’bout storage basins?(much lighter per gallon stored than “gravel & soil”). How ’bout absorbant foam? Sound impractical? More so than trying to maintain live plants in 6″ of “growth medium”?
    Even a lawn connected to Mother Earth turns brown… These “vegetative” roofs need irrigation. And how do you keep your medium/plant/mud mix out of the drains (and sewers)? First, conserve money (short & long-run). Green? I scoff…
    ps I also challenge the notion that having this concoction on the roof surface will lengthen the service life of the membrane.
    Any good, modern membrane, properly installed, is essentially a lifetime system.
    …and try finding a leak under that mess…Hey, Mr Jason!…got a shovel?
    pps Ol’ Jake apparently knows all about no-brainers…inform yerself.
    ppps want a cool roof? Go white-now mandatory in Chicago.

  8. So how exactly does Al Johnson’s Swedish restaurant in Door County deal with all of that? He’s had a grass roof with goat lawnmowers for like 58 years.

    I am not going to defend whether this roof is a long term solution or not, but if it does prove viable the expense because r&d money…

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