I’m looking into a job that involves a green roof over concrete(rubber membrane with grass over it) my rubber roffer is clueless.Doesanyone know anything about it?
Thanks for all the thoughts in the past. Its really niceto get all these opinions and ideas.
Blacky
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Epdm rubber roof.
be sure it has enbough pitch to drain.
The specs should show insulation in there someplace - are there specs or is this a DIY kind of deal?
Then you need a drainage mat material.
Then an inch or two of sand and then the sod.
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specs? well...no the dock plank is engineered 24' span around a 125 #/ft loading 10" block with rebar and filled with crete just needed some thoughts on the roof. I heard somewhere that regular epdm will kill the grass. I had seen a article in a IRC monthly but must lent it out or lost it. I was going to make one wall a course above the other side just to give slight positive drainage. I backfill all my projects with riverrock to grade...never had a problem with water thought about maybe sand on top of epdm maybe 2" and then a 6 mil plastic over that with another inch of sand and then sod.? its not til the weather breaks schedule provided so I'm just thinkin over ideas and tryin to pick some brains in here.
Thanks Blacky
Do a Google search on both "green roof" and "eco-roof". There are a number of web sites that give quite a bit of information about it. I did a search about a year ago but don't have the citations handy. I am planning on doing an eco-roof and will be talking to an architecture professor from the University of Oregon who is somewhat of an expert on it and who has agreed to help with the design.
Some sites divide the eco-roofs into a thick and a think layer of soil. Another division is whether or not you plan on watering it during the dry months. I plan on using a number of dry area plants in mine, but since I am allergic to grass pollen, I hope to avoid using grass.
Is it just run of the mill EPDM, or does it need to be some eco-friendly type like they use for pond liners?
I had access to tons of sued EPDM, but am only using it for making water sheding decks. The pond market went up in smoke b/c the regular stuff will kill the fish.
Dave
http://www.conservationtechnology.com/
An architect friend is using their products on a commercial project.
I'm looking into a job that involves a green roof over concrete(rubber membrane with grass over it) my rubber roffer is clueless.Doesanyone know anything about it?
I live under one, as does anybody else with passive annual heat storage (PAHS). Why use EPDM or butyl? If you're really concerned with waterproofing, bentonite is better. We use 6 mil poly successfully.
What depth soil is the design/roof load? That will determine how everything works.
PAHS Designer/Builder- Bury it!
Bentonite works great in a vertical layer against horizontal movement of water when combined with an alternative passage for water, but it is far from being waterproof. It is permeable and uses the water that it holds to repel other water. however, given enough hydraulic pressure it will certainly leak.
From a practical viewpoint, it is enough for many climates when the sod surface makes use of some water and shed most of the rest, but I would be concerned about living under it in a rainy climate.
Besides, it goes against every thing I have ever learned about underground waterproofing. The bentonite holds the water tight to the membrane. Every detail I have ever seen requires a drainage plane to allow the water to find a way to go OTHER than into the house. Bentonite becomes a damn.
Add one more concern.
The bentonite is very heavy once it soaks up all that water. That means that the underlying structure must be designed to higher load capacity, at higher cost.
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Bentonite works great in a vertical layer against horizontal movement of water when combined with an alternative passage for water, but it is far from being waterproof. It is permeable and uses the water that it holds to repel other water. however, given enough hydraulic pressure it will certainly leak.
Afraid not. It has been successfully used on several government buildings here where membrane waterproofing failed. In our rainy climate, I have used it horizontally successfully. Living under it presently and it didn't leak even before I finished my insulation umbrella. What is required is sufficient backfill pressure. Give us a break, the amount of water retained by a thin layer of bentonite would hardly cause engineering changes.
Furthermore, our state health department is trying very hard to get it used as the waterproofing for all water wells. Works much better than the traditional concrete. Leaks? Not if properly applied.
PAHS Designer/Builder- Bury it!
"Leaks? Not if properly applied."
So, why do you use a few mills of poly?
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Edited 2/13/2004 4:22:15 PM ET by piffin
So, why do you use a few mills of poly?
You're apparently refering to my insulation umbrella, which is a component of Passive Annual Heat Storage (PAHS), not the bentonite waterproofing. For PAHS to work, the dirt under the umbrella must be kept dry. Wet soil moves heat too rapidly to get annual heating. With a properly applied PAHS insulation umbrella, there is no need for waterproofing, other than the insulation umbrella. And my client decided against the bentonite, or any other waterproofing. Turns out he was correct.
For my place, the first house I'd ever built, I was very cautious and did a lot of checking into waterproofing, finding those government installations, and concluding the $1500 for bentonite was well worth it as insurance. Particularly as I was mostly working alone and my insulation umbrella wouldn't be complete before we got rain, several storms. A leaky underground house would be a nightmare.
I used the Paramount product per their suggestions on both my back wall and roof. Nothing was added, other than the backfill, until I finally got around to installing my insulation umbrella. And that's not anything the bentonite manufacturer expects anybody to use to shield their product. Presently the bentonite is only a backup system. Installation on the roof sure was easy. Unroll it and dump dirt on top, watching for rocks.
Let me guess. You had a bad experience with the cardboard surrounded bentonite product? It is reputedly much more difficult to install properly.
Any bentonite is dependent on sufficient pressure to work. And if it gets wet prior to proper backfill, it will likely be ruined. I know from experience.
For this thread's green roof, if the soil depth is only going to be a couple of inches, I wouldn't use bentonite without checking with the manufacturer to determine if that was adequate pressure. Prior to my insulation umbrella installation, mine had 12" of dirt which proved to be sufficient pressure. Obviously that 12"of dirt was sometimes very wet, or the bentonite product wouldn't have seen any moisture. That 12" of wet dirt will definitely affect the engineering, unlike the tiny amount of water that the bentonite can soak up.
I now have 12" of wet dirt on top of my insulation umbrella and built to an engineered 300 psf total load. With steel bar joists, it's very fast and affordable ($5k for 1600 sq ft, including decking, 30' span). Particularly if you consider that it is my maintenance and fuel free heating/cooling system. Re-roofing is extremely unlikely, ever.
For water wells, we pour ½" granules of bentonite around the well casing, down to bedrock. Nothing else is added. The sealing of the bentonite, when it gets wet from surface water, is better than everything else. I've never heard of a failure. PAHS Designer/Builder- Bury it!
Sounds like the summation is that bentonite, like other building materials depends heavily on the quality of installation for success.
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Absolutely.
I did find the rolls of bentonite very fast and easy to install. What's needed is to move fast enough to get it backfilled before it got rained on. A little organization is required. Sometimes difficult for me. This was also my first backfill and I was being very cautious (slow).
The 6 mil poly, which replaced the bentonite for us, of course didn't have that need. I don't think I'd use solely poly without the PAHS umbrella arrangement though. We had a small leak until the umbrella was complete. As you say, installation quality. Redundancy works nicely. PAHS Designer/Builder- Bury it!
The city of Chicago is heavily into the "green roof" thing. You may want to google for info, or call the Mayor's office and ask them to fax you more details.
Fannie May? Fannie May? FIE, I'll take Cookiemonster's exquisite creations anytime.
Some reservoirs use EPDM..enough said?
Be well
andy
My life is my practice!
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Does it have to be grass? Exposure issues(heat and sun) might make for an unsightly mess up there, as well as regular maint. (mower? weedwacker? goat?)Grass w.ll probably need 6-8" of root run with a custom mix to provide proper nutrition and drainage.
Look up www.greenroofs.com for some good general info and http://www.greenroofplants.com for something to think about.
I did an installation this past spring on a slightly pitched carport just off a new porch. From the framing up thereis 3/4 pt plywood, 30# felt, 1/2 " insulation board, 45 mil epdm, geotextile fabric, 1" sheet drain, more geotex, and 3-4" of a custom planting mix(20% compost, 80% expanded slate), then planted with a tapestry of low plants that can take the exposure.(full sun) Worked for me and my customer. Good luck.
Since this is over concrete, you might also think about xypex:
http://www.xypex.com
-- J.S.