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Green roof resources in Los Angeles

wilfz

I am planning on installing a green roof on a house in Los Angeles (Silverlake) and am lookng for an experienced design/build firm or contractor who could carry out the job. It is a small project (about 500 sf).

Anyone out there?

 
Aug 23, 07 3:18 am
treekiller

Wilz-

there are few greenroof experts in LA. katie spitz designed the best known example at the science center. Rana Creek, in NoCal, is are leading expert in the state & they do design/build. Fritz Haeg may be interested (if you plant vegetables) - otherwise your in a desert. Hmmmm, maybe Materials and Applications would be interested. Talk to Rana Creek and Katie Spitz first.

(I'd do it if I was back in silverlake).

Aug 23, 07 9:28 am  · 
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paperboy

My GF works at Greentree Landscaping. They could do it. If you contact them ask for Sarah.


link

http://greentreela.com/v1/

Aug 23, 07 11:47 am  · 
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treekiller

A green roof isn't like planting a garden on the ground. lots of unique conditions that you better find somebody with experience to do it - or you'll end up with lots of dead plants, leaky roof, or worse a collapsed ceiling. Greentrees looks competent when their feet are on the ground, but nothing on their website tells me that they have ever been on a roof. Get a registered landscape architect- too much liability and technical knowhow required to trust an unlicensed 'landscape/garden designer'. you'll also want a licensed contractor with plenty of insurance coverage- this is your roof your messing with.

Wilz- is this a retrofit or new construction? different techniques for both- but it all starts with the structural load capacity for your roof and then the waterproofing.

Check out green roofs for healthy cities - they issue a greenroof design certificate. I'd look for folks with this or built projects.

Again, talk to rana creek if you are serious about doing it right, they know the plants that with thrive in California without supplemental irrigation (and they also teach some of the advanced GRHC courses). they may be able to refer you to local firms.

Aug 23, 07 1:17 pm  · 
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wilfz

This is a second / third story addition. The third story is composed of a 200 sf room with access to a 150 sf deck and the 500 sf greenroof. The house has zero backyard, and minimal (sloped) front yard, so the third story will basically be replacing the backyard(with a nice bonus: views!)

I planned for a 30 lb /sf dead load for the greenroof (in addition to the 10 lb / sf dead load for the roof framing), and a 40 lb /sf live load.

I accounted for a 6" thick greenroof when planning for the different elevations (the top of the deck is to be at the same level as the top of the greenroof, and the finished floor of the room is meant to be 2" higher than deck and greenroof)

I used 1/4" per lf slope for the greenroof and 1/8" per lf slope for the deck. At the time, I thought it would be easier to go with 1/4" per lf slope for the greenroof as it is the minimum mandated for a flat roof in LA, and I did not want to get stuck in plan check. I am now thinking I could probably use 1/8" per lf slope for everything...

The house is being framed right now...

I did quite a bit of online research for greenroof design/build firms or contractors, but I felt a bit discouraged when looking at the different websites, that everybody catered to really large projects...but now I need to get moving!

Aug 23, 07 2:16 pm  · 
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strlt_typ

where is this project?...i want to see?

Aug 23, 07 2:35 pm  · 
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treekiller

wilfz- the slope should be good. some of the more interesting advances in greenroofs use zero slope and drain by hydrostatic head/capillary action. This approach does require convincing the plan checkers that you know what your doing. your loads seem appropriate along with the planting depth- so are you looking for an habitable roof garden? to have larger plants, it helps to have 18" or more of soil in planters (like at the edge).

Rana Creek does seem aimed at large projects, but they are very helpful.

I'm recalling that the tree people HQ or Debs Park may have a green roof - worth looking at them.

Aug 23, 07 2:49 pm  · 
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wilfz

It's in Silverlake, dammson.

Aug 23, 07 2:50 pm  · 
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R.A. Rudolph

We have done a couple of green roofs - one on our own house and one down in San Diego. Unfortunately we're closing down our conatruction company, and we don't have insurance for this kind of work anyway.

On our house the green roof portion is about 350 sf, and the one quote we got from a waterproofing company was about 14K (just for the waterproofing portion, no dirt, plants, irrigation), so we ended up doing it ourselves. We could not find a roofer who would warranty the roof, but we took a chance. My guess is that if you can find someone licensed to do the work, it will be prohibitively expensive on a residence this small. I'm sorry I can't remember the name of the waterproofing company that gave us the quote - I know they were on the westside.

The one we did in san diego was 120 lb/sf at about 4-6" of lightweight soil. On ours, the engineer (different engineer) wanted to use 120/sf as well, but we got her to reduce it to 80 lb/sf. The one we did at 120 lb/sf was a cmu structure w/ a concrete roof deck. On our house we did wood, but the framing for the green roof was insane (4x12 @ 16 oc, plus double sheer walls, huge footings, etc., for a one story structure). We would not do a green roof on top of wood framing again. I can't remember, but I feel like those loads may be for the green roof alone. If that's the case, I would be very worried about putting a green roof on top of what you have described. I'll take a look at my calcs and see if I can find it.

Other considerations are getting the soil onto the roof - both of ours were one story structures with easy access. On the first one they used a converyor belt, on our house we had a blower blow it up onto the roof.

Basically the system we used was a modified SBS Bitumen roof, then rigid insulation board, then an epmd pond liner (double protection), then a drainage mat w/integral root barrier (J-Drain), then lightweight soil. The roof is sloped at 1/4" per foot, drained by crickets to scuppers, with some mesh over the openings to keep the dirt in. The total cost (not including framing) was probably $12K, doing it ourselves including the dirt, plants & irrigation, so I guess that works out to about $35/sf.

Aug 23, 07 3:06 pm  · 
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el jeffe

r.a. rudolph hit on it - for a second and third story, having that weight up that high is gonna create some serious lateral loading.

sorry to hear you're shutting down the construction biz r.a. - i know you had expressed that it wasn't going well in the past.

Aug 23, 07 3:21 pm  · 
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wilfz

Yes treekiller, I am looking for the habitable roof garden experience. Larger plants on the edge...mmhh, I like the idea.

One thingI am not sure about, is if I have planters on the edge (BTW - the edge will be a solid parapet wall), what happens to the 42" railing requirement? Do I then need to be 42" from the top of the planters to the top of the parapet wall? I first thought about this as I wanted to have built-in benches along some of the section of the parapet, and was then unsure that this would work with the 42" requirement (wouldn't I need to measure the 42" from the top of the bench?).

I will get in touch with Rana Creek and if they can help

Aug 23, 07 4:06 pm  · 
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wilfz

r.a. rudolph - I am very surprised by the loads you indicate. I've been reading some of the greenroof litterature and what I read was around 25-35 lb /sf for a fully saturated greenroof 4-6 " layer.

120 lb /sf is equivalent to almost 2 ft thick layer of water on top of your roof.

Aug 23, 07 4:15 pm  · 
 · 
Janosh

Despite the small size (which is definitely going to be a problem) Call a Hydotech rep - they have a fantastic green roof system that we are now using on a second large project. They also have folks that will offer plant materials guidance. In my experience, 8" of soil is about the maximum anyone should need or attempt - more than that and you are just adding deadload with little added benefit. That amount will also allow you to have turf and some larger plants for impact, although you'll need to select plants with shallow root structures that require compatible soil and irrigation conditions as the rest of your plants (zoning irrigation hasn't proven easy for us since the moisture mats normally spread the water out fairly evenly).

This thing is going to cost your clients a fortune!

I think 30 lbs/sf is fairly typically for extensive, non-occupiable roofs. You'd be limited to sedum and similar plant materials.

Aug 23, 07 4:28 pm  · 
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corbusier4eva

No green roofs in Las Vegas. I wish I was in Silverlake...

Aug 23, 07 7:38 pm  · 
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treekiller

turf on a roof???? janosh what are you trying to do with your roof garden?

Aug 23, 07 8:26 pm  · 
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Janosh

What can I say - the CEO wants to practice his short game.

Aug 23, 07 8:55 pm  · 
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R.A. Rudolph

wilfz - I checked my calcs and of course can't figure out exactly what they did, but I did find this email from the engineer who did the concrete roof -

"We used 127 PSF for the dead load (which included the planting material and the weight of the concrete). We used 62 PSF for the live load (assuming fully saturated conditions.)"

I remember I had emailed him about the load because the engineer for our addition had said she would use 120 lb/sf for the green roof, and I thought it should be more like 35 lb/sf (based on my research, probably similar to yours). She agreed to reduce it to 80 lb/sf, and based on the above email plus what the resulting structure was, my guess is that was 80 lb/sf just for the green roof.

Also - these are for innaccessible green roofs - I imagine ti would be even worse for an occupied roof.

Did you have it engineered/permitted to have a green roof? Just curious... we didn't have any problems with the city permitting it, other than they wanted an RR# for the waterproofing, which of course we didn't use.

I checked for the waterproofers # and didn't find it. I'm pretty sure we tried american hydrotech and they don't do residential.

We planted mostly natives with a drip irrigation system, and so far they're doing pretty well although we won't know for sure until next year. Although we were warned against it, we planted quite a few shrubs that grow to 4-6'. They may be stunted by the root system...

Aug 24, 07 1:49 am  · 
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R.A. Rudolph

and thanks el jeffe - it is a bummer but we're just not making enough money. design/build isn't all it's cracked up to be if you're actually doing it legit (insurance, workers comp, etc). we're done with kitchen & bath remodels for the moment - I'll never say never again, but I've had enough for a while.

Aug 24, 07 1:53 am  · 
 · 
wilfz

R.A. Rudolph - Yes it went through plan check without any issue. The plan checker had no idea what a green roof was, but I was lucky I had brought a copy of the Los Angeles City resource guide about green roofs (http://www.fypower.org/pdf/LA_GreenRoofsResourceGuide.pdf) so I looked very legit.

As for the engineer, I gave him the specs (40 lb/sf total dead load including 30 for the green roof, 40 lb/sf live load) and he did the structural calculations with those. The result is 2x12 joists 16" O.C. ...

Based on all the feedback, I guess I am in for a real shock concerning the cost of doing a green roof on a residential project. I am not sure why it would be so, it doesn't seem to be rocket science, nor does it use extremely expensive components.

Aug 24, 07 2:16 am  · 
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R.A. Rudolph

We had the same thoughts, but basically it's the risk of putting something very heavy and unknown (since there are so few of these in LA) on top of a roof... most money issues from construction defects relate to waterproofing failure, and no one wants to take on the risk. It's probably fairly difficult to get insurance because it's such a specialty, not to mention that you really need skilled labor because even though the materials aren't expensive or difficult to install, a little slip up here or stepping on something there could result in eventual failure of the whole roof. And you have to imagine it's a lot more difficult to find and repair a leak when the roof is covered with a thick layer of plants and dirt then if it's just rolled asphalt.

I'm surprised your engineer went with those loads given our experience. Ours certainly seems like overkill, but who knows?? If it rains like it did a couple of years ago, I can imagine after a month of solid rain it could be pretty heavy.

Aug 24, 07 2:26 am  · 
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treekiller

wilz- the specs for the soil mixture are the key. you need a light weight aggregate (expanded shall, perlite or other) with a limited amount of organic material, (ie compost). Rana creek will have some good advice, or find a soil scientist to work this out for you. then you gotta find somebody to mix this up for you...

another direction is the roof in a bag/tray option, that just means high freight costs and more $$$ for the same stuff.

the maximum load is fully saturated soil, but most green roof planting media are well draining and wont stay saturated for very long if there is a break in the rain.

Aug 24, 07 10:49 am  · 
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R.A. Rudolph

we got our mix from - www.americansoil.org
they're in the pasadens area, and they have a lightweight mix that seems to be working well

Aug 24, 07 5:49 pm  · 
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wilfz

Has anybody heard of http://www.agreenroof.com/ ?
They have an intensive system that looks pretty good, and easy to install...
Just looking for alternatives in case the cost of a regular 'built on site' system is prohibitive.

Aug 27, 07 3:01 am  · 
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treekiller

never seen them before. after a quick look, you get what you pay for- their 'simple' system provides little of the advantages that a full blown green roof does- little thermal mass, little stormwater detention, not much additional lifespan for the membrane, et cetera. if you want a quick simple bit of green on the roof, then their system fits the bill. if you want all the benefits and longevity of a vegetated roof, look elsewhere.

Aug 27, 07 10:02 am  · 
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wilfz

I thought I would give you an update. I contacted Rana Creek (very helpful), they recommended Hydrotech for the waterproofing, and that I do everything else myself because it would be prohibitively expensive any other way. I contacted Hydrotech's installers, and got a quote that puts the waterproofing (no dirt, plants, irrigation) at close to $37 / sf!! That's waterproofing only!!

R.A. Rudolph, I can definitely understand why you went your own way.

I am waiting for a few more proposals. If there is one thing that all the green roof literature hadn't prepared me for, that's the incredible cost of doing a residential project...

Sep 4, 07 8:30 pm  · 
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margeandfernferrera

@wilfz please share your updates.  We're in sunny Northridge and about to embark in a home extension project as well.  Although our budget is very minimal, we want to do our part for the environment so we're looking at either solar or a green roof.  Any advise or updates on your project will help!  Thank you! 

Sep 28, 20 12:19 pm  · 
 ·  1
Non Sequitur

What did your paid consultant recommend? I'm sure it was not to dig up a 13-year old thread and ask for free advice.

 ·  1
margeandfernferrera

We!re new home owners and just started doing our research. I was looking at a few roof options online and didn't realize this was a 13 year old thread thanks for pointing that out. As for looking for free advice, isn't that what we all do when we search for things on the internet? Which is how this thread
started in the first place?

 · 
Non Sequitur

We're not in this business to dish out our expertise for free.

1  ·  1
margeandfernferrera

So instead of being rude.. why don't you send your business info or referrals to businesses that i can contact to get information? Too much negativity in this world to add on to man. Spin things for the positive. If you own a business, the negativity and sarcasm doesn't help. We're not planning to build it ourselves just simply looking for resources to PAY.

 · 
Non Sequitur

Since you're seeking anonymous internet expertise in order to counter your architect's professional advise, I doubt your sincerity level.

1  ·  1
margeandfernferrera

Anonymous? Sorry but im not the one who's hiding behind a pen name. My name and last name is clearly listed. No anonymity here Non Sequitur! All the best to you sir/ma'am! I really hope you find it in you to share more kindness in the world because thats what we all need.

 · 
Non Sequitur
.

 · 
margeandfernferrera

And spicy

1  · 
justavisual

you should find a modular system thats easy to throw up and easy to remove when your roof needs maintenance

like this:

https://liveroof.com/products/...



Oct 2, 20 5:58 am  · 
1  · 
margeandfernferrera

Thank you so much! Our architect and builder advises against the green roof because they think that
the cost we would sink into the project plus the

 · 
margeandfernferrera

hank you so much! Our architect and builder advises against the green roof because they think that
the cost and all the work that we would sink into the project outweighs the benefits of it.  So I'm doing my own research - thank you for this very helpful.  

Oct 2, 20 9:54 am  · 
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justavisual

Honestly the cost isn't that big...and with the modules it isn't that much work. It makes a huge difference on heat gain. We have a portion of flat roof on our house and it was like night and day before and after the green roof went up. Much more temperature stable inside after. If your roof can take it, I would advise it every time. Lazy contractors...good on you for doing your own research.


Oct 3, 20 4:25 am  · 
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justavisual

Also if you find modules that are suited to the valley climate (you prob still need to water them sometimes so keep that in mind), you can save up and do it later...make sure your roofing membrane is appropriate for green roof - if not you'll need a simple anti-rooting membrane in between. Any decent manufacturer can advise...

Oct 3, 20 4:30 am  · 
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