[Greenbuilding] epdm vs. tar

[jfstraube]

I have done the same as John using Cosella Doerken's MS-20 product: inexpensive, very very tough, and yes, polyethylene is likely the most benign plastic one can make.


On 2011-09-10, at 4:54 PM, JOHN SALMEN wrote:

> I use platon (the foundation drainage product) as the root barrier - similar
> but not quite the same as the European version designed for roofs (smaller
> dimples on this one) - but it is a polyethylene plastic (little better on
> the plastic scale of things), readily available in NA at reasonable cost
> (compared to anything with green roof stamped on it) and the dimples provide
> a moisture reservoir of sorts and will hold soil on small slopes.
> 
> -----Original Message-----
> From: greenbuilding-bounces at lists.bioenergylists.org
> [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Gennaro
> Brooks-Church - Eco Brooklyn
> Sent: September-10-11 8:49 AM
> To: Green Building
> Subject: Re: [Greenbuilding] epdm vs. tar
> 
> Michael,
> That sounds like a bombproof roof. My thought would be that maybe you
> could get away without doing the two layers of torchdown.
> I have asked some other green roofers and they agree that EPDM is a
> good first choice. It performs two functions - waterproofing and root
> barrier. You can do torchdown but then you have to install a solid
> root barrier, and we're not talking those cheap rolls of black felt
> you buy in garden centers. It has to be the kind that is used to keep
> tree roots and bamboo from spreading, which at that point you might as
> well just do the one step EPDM.
> I have seen torch down roofs laid with plastic and then the green
> roof, but the roofers I've spoken to agree that you are not creating a
> long term root barrier.
> Gennaro Brooks-Church
> 
> Cell: 1 347 244 3016 USA
> www.EcoBrooklyn.com
> 22 2nd St; Brooklyn, NY 11231
> 
> 
> 
> 
> On Sat, Sep 10, 2011 at 1:06 AM, Michael O'Brien <obrien at hevanet.com> wrote:
>> Hi, Gennaro--
>> 
>> We used two layers of asphalt torchdown over plywood to seal the roof, and
> then we laid EPDM over that, mainly to create a root barrier as plants can
> get through asphalt. Our roof is sloped so we installed perforated metal
> dividers horizontally to prevent our planting mix from sliding on the EPDM.
> Four years on, seems to be doing fine.
>> 
>> Best,
>> 
>> Mike O'Brien
>> 
>> 
>> 
>> On Aug 28, 2011, at 8:13 PM, Gennaro Brooks-Church - Eco Brooklyn wrote:
>> 
>>> Let me be more clear. I install EPDM roofs and green roofs on top of
>>> that because I think it is better than a simple roll on tar roof. So I
>>> get a lot of clients coming to me wanting me to explain why they
>>> should do EPDM (and maybe a green roof) instead of roll on. I'm
>>> looking for substance from you all to add to my explanation. I'm not
>>> sure I have my facts right or maybe I'm leaving something out.
>>> 
>>> Here is what I say more or less.
>>> Tar roof - lasts 10 years, $10 to install (for argument sake)
>>> EPDM - 20 years, $20 to install
>>> Green roof - extends EPDM by 10 years, $20 to install
>>> 
>>> Tar roof needs to be cleared off every three layers - $10 to clear off.
>>> 
>>> So....over 30 years.
>>> Tar roof - $40, more petro chemicals consumed, more waster created.
>>> EPDM + green roof - $40, not including cooling savings (any guess on
>>> this?), quality of life, no heat island effect, reduced water run
>>> off...
>>> 
>>> Your thoughts? How do my numbers look?
>>> 
>>> Gennaro Brooks-Church
>>> 
>>> Cell: 1 347 244 3016 USA
>>> www.EcoBrooklyn.com
>>> 22 2nd St; Brooklyn, NY 11231
>>> 
>>> 
>>> 
>>> 
>>> On Sun, Aug 28, 2011 at 8:35 PM, Gennaro Brooks-Church - Eco Brooklyn
>>> <info at ecobrooklyn.com> wrote:
>>>> Hi,
>>>> Does anyone have life span of EPDM vs. typical tar roll on roofs?
>>>> Gennaro Brooks-Church
>>>> 
>>>> Cell: 1 347 244 3016 USA
>>>> www.EcoBrooklyn.com
>>>> 22 2nd St; Brooklyn, NY 11231
>>>> 
>>> 
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>> 
>> Mike O'Brien Photography
>> 1905 N Alberta Street
>> Portland, Oregon 97217
>> 
>> 
>> 
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John Straube
www.BuildingScience.com