2Qs: non-toxic insulation & rain water collection

Guest User
2/9/2005
Hi; We're building a house in the islands of southern British Columbia. Rainy winters with lows around freezing and dry sunny summers with highs around 32C/90F. The wet winters make organic building materials less atrractive than inorganics. We have chemical sensitivities and want to avoid VOCs and materials that offgas. We will be building with rammed earth walls and decorative concrete floors for these reasons. Fresh water is an issue on the island so we plan to collect rainwater. We understand that enamel steel roofing is the way to go for rainwater collection. Here are my questions: Q1) Can you recommend a non-petroleum based insulation material (without VOCs) that will work well with steel roof trusses? Q2) Can you tell me about the various characteristics of enamel steel roofing and what tradeoffs we'll make when finding the product that is best for our application? Please (also) email me at [email protected] as I am not a regular reader. Thanks in advance, =dave=
Allan Reid
Dura-Loc Roofing Systems, Inc.
2/9/2005
One needs to look at the roof as an assembly which is comprised of an interior finish, monolithic air barrier,insulation, moisture barrier and roof covering. Within this assembly you must provide ventilation. In an attic structure you would ventilate the attic above the insulation. In a vaulted ceiling you would ventilate between the roof covering and moisture barrier. To the best of my knowledge, fiberglass insulation is the most inert. Choose a roof covering type and contact the manufacturer with your assembly description and get their recomendations. The key will be the monolithic air barrier and if you choose drywall on the interior, apply oil based paints and seal along the floor and all openings. To the best of my knowledge all residential roof coatings are safe to collect the rain water. In fact you will have greater risks with the rain itself. I would say that you should specify a PVDF or SMP paint system or a granular coated roof, as they will provide the best weather resistance.
Guest User
3/5/2005
Allan, Please see the similar question and very different answer I received from another expert, Todd Miller, and my subsequent comment. Can you offer any more insight or advice on this issue. Seems the 'experts' have different perspectives, which it would be nice for us consumers if you could reconcile. Thank you very much for your assistance - see messages below: Respectfully, Jim Jim Ryan 1 Posts "Rain Water Harvesting" Posted On: 02/27/2005 06:51 Dear experts, There has been a proliferation of different coatings and paints factory applied to metal roofs, is there a guide to which of these is safe (hopefully tested) for producing potable water when used as part of a rain harvesting systems? Obviously anti-fungicidal coatings are likely to be un-safe to use, what about the others? And while we're at it, what is the best metal roof to use for rain harvesting, ie the roof material which will not react with and pollute the water, and which maintains a slippery clean surface which quickly sheds accumulated dirt when the rains first strike it. Thank you! Jim Todd Miller 75 Posts "Classic Products, Inc." Replied On: 02/27/2005 10:27 Many quality paint systems are often applied after the metal has been treated with a chromium-containing pre-treatment solution. This solution is rinsed and then covered with paint but, still, no manufacturer is going to suggest the use of their panels for drinking water collection if therr is a chance that chromium pre-treat was used on the metal. I would suggest bringing this subject up with individual manufacturers but, given today's liability environment, I doubt any manufacturer of any prodouct is going to say "Yeah, go ahead and drink water froom my roof." Jim Replied On: 03/05/2005 05:07 Todd, How do you square your answer to my question with the answer to a similar question from your expert Allan Reid who says.... "To the best of my knowledge, all residential roof coatings are safe to collect the rain water. In fact you will have greater risks with the rain itself. I would say that you should specify a PVDF or SMP paint system or a granular coated roof, as they will provide the best weather resistance". Also, I know in countries like Auistralia and New Zealand, it is standard for metal roofing companies to specify which roofing systems and coatings are approved for potable water collection. Could you at least give me the meanings of the PVDF and SMP paint systems? Thank you, Jim
Todd Miller
Isaiah Industries, Inc.
3/5/2005
There may be a difference here between what is practiced in the real world (Allan's responses are correct) and what a paint producer's answer will be from a legal standpoint. In my experience here in the USA, coatings producers are reluctant to say that collected water is potable. From a practical standpoint, it may very well be potable because it is indeed used a lot as drinking water but imagine if someone who drank the water contracts cancer later in life. There would be no way to prove whether the collected water was or was not an issue in the illness. In today's litigation-prone society, I can understand the paint producer's standpoint. I would suggest finding a metal roof you like and then contacting the manufacturer to get their direct response to this question. PVDF is a polyvinylidene fluoride finish and SMP is siliconized modified polyester. Two different paint technologies and chemistries, both similar pre-treat done to the metal prior to coating.
Guest User
2/28/2010
Dave, Have you found out any answers to your questions that satisfy? I am trying to find out about the safety of rain runoff from metal roofs for watering edible landscapes. [email protected]
Guest User
3/9/2010
#1- Soy based spray foam insulation is petroleum-free and exhibits the exact same thermal resistance properties and oil-based. #2- We have potable water polyurea coatings available that would be able to coat your roof with. Filtering and purifying the water afterward would be your responsibility.
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