Green Roof

[sheldonrf]

I am designing a green roof, I have the roof setup as the following: (from the bottom up)

Concrete roof deck
Insulation layer (about 1" of styrofoam like material)
Waterproofing build up layer (about 6" thick)
Air Layer (1/2" thick)
Root barrier membrane (4mm thick or about 1/8")
Reservoir sheet (1 5/8" thick) - actually looks like some egg crate
Followed by either - gravel rock / pavers / "growth media" (I assume to be dirt) and grass all of these are in the general category of 3" deep

Here is my conundrum.... I am installing power throughout the roof area and I need to run conduits. My overall depth is generally about 12 inches. I can not run my conduits in the insulation layer as it will cause condensation issues on the slab in the space below (which is already at a VERY high humidity), the client understandably does not want roof penetrations all over the place for the multitudes of receptacles that I need to place everywhere. Would this application even be considered direct burial? There is no AHJ to go to and ask, I have to derive this through the NEC and tell them. I plan to install all schedule 80 PVC (but that can change). Any advice is greatly appreciated......

 

[GoldDigger]

Air layer? How do you do that? And does it double for drainage?

I would imagine that either in the reservoir layer would be least disruptive. Or else in the rock/growth medium and hope it does not get dug into later?

 

[brantmacga]

Roof pyramids?

https://m.erico.com/category.html?category=R532&country=us&language=en


Sent from my iPhone using Tapatalk

 

[hbiss]

I think this is supposed to look like a landscape, not a roof.

-Hal

 

[Ponchik]

I would guess all of your roof penetrations can be confined in one specific area of the roof then use roof pyramids as Brant has suggested and install it on the reservoir layer as GD suggested.

 

[steve66]

I'd say the burial depth requirements don't apply.

I think its safe to say nobody should be digging deep enough to get into the insulation or roof membrane, or anything under the top layer of growth material.

And its very unlikely there will be a backhoe or bulldozer or anything similar on top of the roof like you might normally have with buried conduits and cables.

I'd use conduit and not worry about the depth requirements in 300.

 

[Fulthrotl]

I am designing a green roof, I have the roof setup as the following: (from the bottom up)

Concrete roof deck
Insulation layer (about 1" of styrofoam like material)
Waterproofing build up layer (about 6" thick)
Air Layer (1/2" thick)
Root barrier membrane (4mm thick or about 1/8")
Reservoir sheet (1 5/8" thick) - actually looks like some egg crate
Followed by either - gravel rock / pavers / "growth media" (I assume to be dirt) and grass all of these are in the general category of 3" deep

Here is my conundrum.... I am installing power throughout the roof area and I need to run conduits. My overall depth is generally about 12 inches. I can not run my conduits in the insulation layer as it will cause condensation issues on the slab in the space below (which is already at a VERY high humidity), the client understandably does not want roof penetrations all over the place for the multitudes of receptacles that I need to place everywhere. Would this application even be considered direct burial? There is no AHJ to go to and ask, I have to derive this through the NEC and tell them. I plan to install all schedule 80 PVC (but that can change). Any advice is greatly appreciated......

schedule 80 pvc above the insulation. i'd consider short pieces of nonferrous
unistrut glued down to the insulation with a mastic that won't attack the insulation.
actually, what i'd do, is shoot 1 5/8" strut directly to the concrete, put everything in,
and then use an appropriate spray urethane insulation over everything. the urethane
will bond to all of it, and you won't have any leaks, exfiltration, etc. picking the correct
product to spray can also get you LEED points, if that is an issue.

pull wire and whatnot BEFORE anything else is put over the top. just a thought. and where
you have to stub up to a bell box, use GRC instead of plastic, and clamp it to the strut
with strut straps tightly.

 

[sheldonrf]

Air layer? How do you do that? And does it double for drainage?

I would imagine that either in the reservoir layer would be least disruptive. Or else in the rock/growth medium and hope it does not get dug into later?

I do not believe it will be dug into. I am not sure how the air layer works...

 

[sheldonrf]

Roof pyramids?

https://m.erico.com/category.html?category=R532&country=us&language=en


Sent from my iPhone using Tapatalk

I am not sure where I would install the roof pyramids, it is a landscaped area essentially and they want a "clean" look.... (not like anyone will really see it)

 

[sheldonrf]

I think this is supposed to look like a landscape, not a roof.

-Hal

Yes it is.

 

[sheldonrf]

I would guess all of your roof penetrations can be confined in one specific area of the roof then use roof pyramids as Brant has suggested and install it on the reservoir layer as GD suggested.

Yes, we have several penetrations in one location then the conduits run all over the roof to supply power, lighting, and communications.

 

[sheldonrf]

I'd say the burial depth requirements don't apply.

I think its safe to say nobody should be digging deep enough to get into the insulation or roof membrane, or anything under the top layer of growth material.

And its very unlikely there will be a backhoe or bulldozer or anything similar on top of the roof like you might normally have with buried conduits and cables.

I'd use conduit and not worry about the depth requirements in 300.

Thank you. Yes, no one will be up there with any heavy equipment.

 

[sheldonrf]

schedule 80 pvc above the insulation. i'd consider short pieces of nonferrous
unistrut glued down to the insulation with a mastic that won't attack the insulation.
actually, what i'd do, is shoot 1 5/8" strut directly to the concrete, put everything in,
and then use an appropriate spray urethane insulation over everything. the urethane
will bond to all of it, and you won't have any leaks, exfiltration, etc. picking the correct
product to spray can also get you LEED points, if that is an issue.

pull wire and whatnot BEFORE anything else is put over the top. just a thought. and where
you have to stub up to a bell box, use GRC instead of plastic, and clamp it to the strut
with strut straps tightly.

I will make these suggestions to the architect. I am not sure what they will say. As well, I am only the designer, so I can make suggestions, but ultimately the Architect and the client will make the final determinations, I can only make recommendations.