Green Roof Reno
April 26, 2008
Go Green Expo
Just a quick note to say that if you are interested, you should check out the Go Green Expo this weekend. . . .
There will be some green roof and green wall suppliers on hand with their products.
The Hilton New York
Saturday 10am-6pm • Sunday 10am-3pm
See the project below from Seoul, Korea by Mass Studies Architects using G-Sky Living Wall Panels . . . A similar product by Green Living Technologies will be on hand at the expo . . .
April 22, 2008
Into the Ceiling
So even though Spring is here . . . We're still inside trying to figure things out. Our next step was to determine the structural load capability of the roof in order to determine how to proceed with getting the deck and green roof built. So we had to go into the ceiling and look at the beams.
I was excited to inspect the roof from below – to see the size and condition of the beams holding up our roof and measure their spacing. I choose the side of the skylight to cut into the drywall so that it would be least intrusive. It would also allow us to look above the ceiling without actually cutting into it. After removing a 10” x 18” drywall piece in the side of the skylight niche, I caught a faceful of some really old air. I mean who knows when this space was last open?
What we found was true 3” x 7” beams that are spaced 24” apart on center. From what I understand this is not great news . . . the depth of the beam is the key number here and seven is just not that impressive. New wood decks are often framed off of 2x12s spaced 18” to 24” on center . . . in other words with a lot more load capability.
On the positive side, the quality and integrity of the beams seemed intact; with no dampness etc., though one of the beams looks like it had some water staining at some point. Everything up there now seems dry as a bone. We actually have about 12 inches of space between the ceiling and the roof, which means we could raise our ceilings if we wanted to. Right now, it’s not even a consideration, with all our money and resources devoted to the green roof project.
One key thing to note, the load-bearing walls do not extend to the ceiling (12 feet) but stop at the fourth floor ceiling (11 feet). In this case, the load-bearing walls are the interior walls that run down the center of the building separating our apartment from our 4th floor neighbor. So what that means is that we will consider cutting into the roof and building up that load bearing wall to form a 2’ high parapet in middle of the roof. We would then frame the deck, and if need be, the green roof off this parapet and the side parapet.
But, we still have a lot of questions - What can we expect to pay for building up a 2’ parapet from the load bearing wall? How does this differ price-wise from using steel? We would like to still consider using steel, but want to know the price differential between these options. Is steel two times more expensive or ten times more expensive? Will the 3x7s at 24 inches on center be enough to support the 17 lbs/sq ft of the green roof modules?
April 2, 2008
The Meeting
Finally we met with our structural engineer, “Bob,” an old timer who seemed to know his bricks from his beams. Bob was recommended to me by a friend in the construction business who talked about him as someone who “knew how to get things done in Brooklyn.” We had chatted on the phone so he had a good idea of what we were after.
Bob was a wealth of information – both practical and historical. Although typical homes in Park Slope allow for a load of about 40 lbs/sqft, Bob said that sometime around 1950 they realized they didn’t need quite that load and resized things down a bit to 35 lbs/sqft. Since our building is from 1920 we should theoretically be able to handle more weight than some newer construction, but I guess we would also have to factor in the age of the beams. One thing we didn’t think of was that the ceilings of our apartment have to be factored into the load calculation, as they hang off the roof beams. Also included in that number should be the roofing material, of which there may have been three or four layers applied throughout the years.
I was beginning to think my green roof modules were doomed! At roughly 15-20lbs/sqft when saturated – could these work on our existing roof? Bob had a lot more questions, for instance - Where are the load-bearing walls? What size are the beams and how far apart are they?
His thought was that our type of building, a 29ft x 60ft building with a central staircase, would typically need to be supported by two load-bearing walls in order for the single wood beam to span the 29 ft across without sagging. A quick trip to the basement confirmed that our building had load bearing columns each about 10ft offset from the side walls of the building. See the image below for the 1936 basement plan with my annotations – my trip to the DOB was worth it after all!
Essentially what this means is that we could cut through the roof and build up from that load bearing wall to create a low wall, or parapet, in the middle of the roof. We could then frame the deck off that wall and the side brick parapet. Obviously the next steps are contingent on the investigation of the beams, but Bob’s feeling was that the green roof modules would be okay! Let’s hope those old builders in the `20s overcompensated on their structural load calculations.
Without original building plans, we will have to do some investigating into the beam size and spacing. So . . . we’re looking forward to cutting a hole in the ceiling! We always wanted to see if we could ever raise our ceilings higher – now here’s the chance. We’ll let you know how that goes . . .
We were also a little surprised to learn that architect, engineer, and permitting fees could be close to $5000 for even something this simple. In most cases, design and permitting fees should be between 10 and 20 percent of the total construction cost. So these projected fees definitely have us concerned, as they could be more than we’ve planned for. In any case, we’ll feel better about having it permitted, both for our own peace-of-mind and ease of resale somewhere down the line.
While this meeting was productive in moving the process forward, we still felt left with more questions than answers. Until we do our own investigations (i.e. the pending hole in the ceiling) we won’t really know anything. We also left feeling that we wanted a general cost comparison between using and not using steel on the roof. All you structural engineers out there - feel free to weigh in right about now!
Although we don’t want to get into specifics on finances, we understand it may be difficult to budget for these types of projects, so we will answer your budget questions by email. Also, we know how hard it is to find good people, so . . . we would be happy to share additional info about our structural engineer and other friends. Drop us an email at greenroofguy@gmail.com.
March 23, 2008
Tomorrow and the D.O.B.
Sorry to have not followed up on our last post . . .We had some minor scheduling issues with our structural engineer (actually his secretary made a mistake and we were stood up). But we finally have our meeting scheduled for tomorrow. Sound like déjà-vu? Yeah, us too. But we’ve looked for the silver lining in this small setback and expecting tomorrow to be great!
The delay did give us an opportunity to do a little extra research. We realized it might be a good idea to take a trip down to the DOB and try to find the original plans and/or structural modifications to the building. I followed the instructions found in a great comment here:
http://www.brownstoner.com/forum/archives/2008/02/help_finding_in.php
We know our building was built in 1920 and was last modified in 1987. We were hoping that the original plans might be on file. We were also hoping to find any drawings relating to the structural modifications in ’87 which we believe included reinforcing the staircase and adding a central beam in the basement.
So the DOB is quite an adventure . . . After getting my block and lot number via PropertyShark.com, I headed downtown last Wednesday. A friend told me if I had my block and lot number I should just go directly to the 1st floor. Well, that turned out to be wrong . . . They sent me to the 2nd floor, who sent me to the 7th floor who sent me to the 8th floor where I finally found the correct window, only to be told that I needed to get a ticket and this form signed at that other window before they could help me. I felt like I was in one of those futuristic movies of bureaucratic hell (a la Brasil) . . . finally, though, when I reached the person who brought up the records, they were very helpful and the process only took about 15 minutes.
Unfortunately for us, we totally struck out. Our building had no microfiche plans and the folders of past DOB filings only included permits and an old basement plan from 1946. We’re hoping the structural engineer can tell us more . . .
March 6, 2008
Judgement Day . . . Maybe
Sedum Trays
These are all 4 inch aluminum planting trays manufactured by Green Roof Blocks out of St. Louis, Mo. This is an extensive module sedum tray system and one of the better products we have seen in the lower price range. With an unlimited budget, we would love to install a seamless, integrated green roof system (more like a carpet as opposed to the modular system shown here, and unfortunately, for small sites, more pricey, too), but most of the companies that do this type of work focus on much larger projects, usually upwards of 5000 sq ft.
Steel – Yay or Nay?
Our day with the structural engineer has finally arrived! We’ll definitely snap some candids and post on the momentous event that’s happening tomorrow morning. Also, we’ll talk about the whos and hows and whys of dealing with a structural engineer after we have a chance to meet with them.
Thanks for reading.
February 13, 2008
Making Progress
The Meeting
So we finally had a chance to sit down with the co-op board last weekend. We brought a brief project introduction and a couple of drawings to illustrate the conversation. Things went well and they seemed responsive to a lot of ideas we brought up. We explained our project and talked about the tax and energy benefits to the building . . . which of course they loved.
We presented our preferred option; a 200 sq ft wood deck with a 550 sq ft green roof. It’s economical for us and energy smart for the building. The way we construct and install the deck, however, depends entirely on the structural engineer. If they say the roof can’t hold the weight of the deck and green roof, then we need to lay down steel I-beams. The steel would extend from parapet to parapet (or from side property edge to edge and essentially across my neighbors half of the roof) and we would build the roof deck on the steel. Our neighbor would have to okay this, of course, which is another story in itself . . . Steel would allow us to do almost anything, which could be fun but, will most definitely be major expensive.
Questions
We could only go so far in the co-op meeting -- all decisions for the roof now seem to rest upon a structural analysis. We have some real questions for the structural engineer at this point, like:
- Can the existing roof hold the prescribed saturated weight of the green roof blocks and the wood deck?
Green roof blocks = 17 lbs/sq ft (saturated)
Cedar deck = 30 lbs/sq ft
Ipe deck = 65 lbs/sq ft
- Is the staircase bulkhead a supporting wall and can we anchor-bolt wood beams to it as a support for a wood deck?
- If we need steel beams to support a roof deck and vegetation, how much steel do we need? How thick does it have to be? And where should it go?
Of course, the board did have concerns – they wouldn’t be a board if they didn’t . . . Apparently the building has had problems with the roof in the past (we’ve heard rumors of someone nailing decking directly to the roof membrane – ouch!). They asked some good questions . . . What would happen if the roof had to be fixed? How would they get to it? Would it invite people from adjoining rooftops to “vacation” on our deck? Would plant material get caught in the roof drain? Totally valid questions – some of which we’re still trying to figure out ourselves.
Stormwater
Oh yeah . . . We almost forgot to mention. It turns out that our building is having stormwater issues. We were sure to mention in our meeting how a green roof would capture a significant amount of the roof’s would-be stormwater . . . a perfect solution to their problem. We really seem to have gotten lucky with our co-op board; they have been very open and interested so far. . . fingers-crossed.
We'll keep you posted. Mr. and Mrs. Green Roof
January 22, 2008
Oh . . . the Possibilities!
When we dream . . . we dream green. Lately it as though we wake up and imagine weekend mornings with [iced] coffee and the Times on the roof deck surrounded by greenery and the city and the sky. We definitely want to be eco-conscious in this project but we also want it to be affordable and comfortable . . .Hopefully, these ideas go hand in hand.
We realize, of course, that green roofs have been done before. In fact, Europe and especially Germany can be considered leaders in the field with 35 to 40 years of tested green roof installations. Projects in the States can be found burgeoning in every major city. We hope to be one small piece of the puzzle; contributing our part to the greater ecological challenge we face as a country.
Approaching the Co-Op
Right now, we are in the process of putting together a package to present to our co-op board. We’re definitely anxious about getting over this hurdle as things seem to always be tricky when dealing with co-op boards. . .
We’ll present this project for what it is; a private space for us, but also a benefit to the long term health of the building. Green roofs have lots of benefits, from savings on heating and cooling costs to increasing the life of your current roofing system by two to three times. Other positives of installing green roof systems include the city-wide effects of stormwater retention and the mitigation of the urban heat island effect. The new New York City PlaNYC [www.nyc.gov/2030] from Bloomberg proposes a 35 percent tax benefits for green roof construction costs. We hope to figure out how to take advantage of this!
To clarify, we own the roof rights to the space directly above our apartment (essentially half the roof space). We will pay for the installation of the roof deck and green roof on the portion of the roof we own. As part of our package for the Co-op we might include options like offering to green our neighbors’ roof space at the same time per their expense or the co-op’s . . . That would of course be an ideal situation because it would unify the design of the project while providing a maximum benefit for our investment. We will also present a proposal for a structural analysis that will determine whether an extensive green roof and deck is even possible. With steel or without, we are confident we will be able to create something beautiful.
Green Roof Images
These images inspire us – we’re thinking architectural, sleek, with defined edges . . . plantings in masses that change in color throughout the seasons.
Green Roof Plants
You can get green roof plants from a ton of places and we’re going to explore a bunch of them, ordering samples and giving reviews. The plant options for a green roof are literally through the roof – there are zillions of choices and the hard part is choosing the right plant for the right climate and site. The manner in which they are delivered is also varied; being offered by companies as mats, blocks, carpets, tiles, grids, modules, and paks. We’ll have a lot of choices to make to make in the next few months . . .
Mr. and Mrs. Green Roof
January 13, 2008
Going Green
An Introduction
Hello! We are Mr. and Mrs. Green Roof looking forward to bringing you the play by play from our foray into the world of green roof design and construction. We recently bought a one bedroom apartment with roof rights in a four story, eight family co-op building in Park Slope. The roof has tremendous potential to be an outdoor extension of our interior living space while at the same time doing something positive for the environment, so we thought we’d share the process of transforming it with you.
Our Project
To research, design and implement a 750 sq ft green roof in Park Slope, Brooklyn. Because of the panoramic views--which include the Manhattan skyline and glimpses of the harbor and passing ships, New Jersey, and the Verrazano-Narrows Bridge--this space would especially benefit from a deck and some greenery. We see this as an opportunity to not only increase our quality of life but also bring value to our home. The goal is to create a wooden deck with potted plants, comfortable furniture and some kind of shade structure like a wooden trellis on about one-third of the roof. The remaining two-thirds would be covered with an ecological or extensive green roof.
Although the roof is technically shared (split in half between us and our fourth floor neighbors) and the staircase is shared by the interior hallway of the co-op, when you get up the roof itself, it feels fairly empty and quiet and really peaceful. Disconnected from the street by the height of building and a five-foot high parapet (a low wall at the edge of a house-top) on street side, you can hear the rustling of the leaves on nearby trees and the unusually strong winds howling in your ears.
Green Roof
Typically there are two types of green roof systems, extensive and intensive. An extensive green roof has low, desert-like plantings designed to provide maximum green coverage while requiring only two to four inches of soil. Intensive green roof systems are more of a typical roof garden with trees and other large plantings which require several feet of soil depth and a steel frame.
We think implementing an extensive green roof is a cost-effective and ecologically sensitive way to bring mass greenery to our roof. We hope that by using plantings like sedum and using lightweight soil we will be able to have close to 500 sq ft of green space on the roof. We hope to get the okays from our co-op board and a structural engineer to install the green roof system directly on top of the existing roofing membrane. Throughout the process we’ll be researching different products and books and sharing our reviews.
Deck
A deck will provide us with a great outdoor hang-out, dining and work space. We hope to make it simple and beautiful and do most of the work ourselves.
Because the roof has a parapet on three sides (two ft high on the north and south sides, and five and a half feet high on the east side), the view, right now, is restricted while seated. Therefore we plan to raise the elevation of the deck two feet above the current roof, increasing views, and meeting many of our major aesthetic goals for the project.
Why We’re Documenting
We are really passionate about doing this. With all the constant green this and green that, in a world where green has become a marketable commodity; we hope that people see our project and want to do their own roof garden. Brooklyn is a pretty dynamic place and we wouldn’t be surprised if it became a leader in realizing green neighborhoods and helping New York to become an eco-city. Bloomberg supports this vision and we definitely recommend checking out his PLANYC report on sustainability. In any case, we are excited and anxious about the possibilities and pitfalls. We’ll do our best to post nice photos and a detailed look at the process. Happy reading!
Mr. and Mrs. Green Roof