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Roofing Materials? - asly - 02-25-2010
So... did we ever figure out what type of roofing material is the best in the east Hawaii environment for water catchment purposes? I know I saw some posts regarding that and folks doing research, just wondering what the final consensus was/is?
Enjoy the day! Ann
Back to blogging at
http://crazypineappledream.blogspot.com
RE: Roofing Materials? - Obie - 02-25-2010
From the UH brochure on catchments.
Roofing
Ideally, only materials approved by the Food and Drug
Administration or the National Sanitation Foundation
would be used to catch drinking water. Unfortunately,
no roofing materials have been approved for drinking
water catchment use. The National Sanitation Foundation
has approved epoxy coatings for drinking water use
that can be painted over a surface, but these coatings are
very expensive, have an effective life span of only about
seven years, and were made for coating the interior of
tanks rather than roofs and gutters.
The most common type of roofing material used for
water catchment is galvanized metal that has been
painted or enameled with a nontoxic paint. Other materials
that could be used are concrete, terracotta tiles,
slate, polycarbonate, and fiberglass.(2) Paint used on the
roofing material should not contain fungicides or other
poisons that could leach into the water. Materials containing
lead should not be used anywhere in the catchment
system. Lead is a serious problem with older homes
because not only the paint but also nails, flashings, solders,
and gutters could contain lead. Lead-based paint
was not manufactured in the United States after 1978,
but these paints were still in circulation after that time,
so if your home is an older home it would be wise to
have the paint checked. Simple, inexpensive test kits
can be purchased at local hardware stores to test paint
or surfaces for lead. In addition to lead, avoid using roofs
that contain uncovered zinc, asbestos (which can be
mixed into concrete tiles), tar, asphalt, or pesticidetreated
wood.
With a new roof, always divert rainfall away from
the catchment system for the first few rainfalls. Let the
roof rinse off and weather a bit before attaching the gutter
system to the tank. The first rains will help flush away
dust and debris such as metal shavings from the new
building materials and keep these materials out of your
tank. New paint, especially acrylic paint, could leach
substances such as detergent into the tank that could
cause the water to froth.(2) Before connecting your tank,
catch some runoff in a jar and check to see if the frothing
has stopped.
In designing a roof for catchment purposes, keep its
pitch relatively low to maximize the amount of water
that gets into your gutter. A steep roof can cause water
to splash out of the gutter.
RE: Roofing Materials? - asly - 02-25-2010
interesting - thanks Obie. When it says near the end to check to se if the frothing has stopped, what is that from?
Enjoy the day! Ann
Back to blogging at
http://crazypineappledream.blogspot.com
RE: Roofing Materials? - JonP - 02-25-2010
"New paint, especially acrylic paint, could leach
substances such as detergent into the tank that could
cause the water to froth."
RE: Roofing Materials? - hotinhawaii - 03-12-2010
I have used Firestone Ultraply TPO roofing membrane on four homes I have built in Puna which are on catchment. It has a very low leachate rate especially compared to EPDM rubber. It may also comply with the new energy code which will take effect in March 2010. This will require all roofs to be insulated or comply with a cool roof requirement. Using this roofing could save the cost of insulating your roof structure.
RE: Roofing Materials? - asly - 03-12-2010
So, this is a membrane that you paint on?
Enjoy the day! Ann
Back to blogging at
http://crazypineappledream.blogspot.com
RE: Roofing Materials? - JWFITZ - 03-12-2010
Don't worry about it-- invest your money in a quality filter. I like the zincalum roofing but it only comes in "INDUSTRIAL JOY" coloring. . .
Really, filtration systems have come a very long way and are regulated with standards far beyond most consumer appliances. It would be easy and relatively inexpensive to purchase a filtration system that could utilize your septic tank as your water source. . .so don't worry about the roof.
Frankly, I get sick most every time I drink much local county water. The cleanest water in the world falls from the sky-- enjoy it!
Be sure you pay intelligent attention to balancing the PH, which is why as far as I'm concerned only concrete tanks are worth considering.
http://sensiblesimplicity.lefora.com/
RE: Roofing Materials? - JWFITZ - 03-12-2010
Oh, and I would counter also the UH thing Obie has posted about roof pitch. Go with 6 12 if you're someplace it rains "puna style." You'll have plenty of rainfall and it's useful to blow all the crap right off your roof over the gutters. Debris on a low pitched roof will sit up there and rot.
http://sensiblesimplicity.lefora.com/
RE: Roofing Materials? - asly - 03-12-2010
Hi Jay! Thanks for the info.
Enjoy the day! Ann
Back to blogging at
http://crazypineappledream.blogspot.com
RE: Roofing Materials? - hotinhawaii - 03-13-2010
TPO is thermoplastic polyolefin and comes in white, tan and gray. No need to paint or coat it ever. Relying on a filter to take out contaminants that you know you are putting in your own water with your roofing choice seems like Russian roulette to me! Why not keep your water as pure as possible all along?
As far as water flushing debris over the gutters, a properly designed roofing and gutter system will NOT flow over the gutters in a heavy rain. If it does, the gutters are not designed or installed properly. If you want to flush contaminants from the roof, consider a downspout filter and first flush diverter system. Some of the best on this island are designed in Australia where, because of a decade long drought, they have studied this subject to the nth degree. They are sold at Waterworks in Hilo. You can view them here: www.rainharvesting.com.au