[OKC] Fw: [RunningOnEmpty2] Fw: [permaculture] Whitewash for roofs?

Mon Aug 8 21:19:49 PDT 2011

At my runningonempty2 at yahoogroups.com discussion group, and at the permaculture ibiblio listserv, I’ve been inquiring about using whitewash as a cheap way to get a white roof.  Here is a thread of answers from the permaculture listserv that pretty much sums up the results.  

Executive summary: it works, one guy estimates it cut his electric usage by 30%, it lasted him 2 years in St Louis before he had to reapply.  It costs maybe $15 to do your roof.

This is worth passing around.

Bob Waldrop, OKC

From: Bob Waldrop 
Sent: Monday, August 08, 2011 11:14 PM
To: runningonempty2 at yahoogroups.com 
Subject: [RunningOnEmpty2] Fw: [permaculture] Whitewash for roofs?

I posted this same question to the I-biblio permaculture listserv. Here is 
a short thread of answers from a guy who did this and figures it cut his 
electric usage by 30%. Yes, it eventually washes off but it lasted pretty 
good (2 years in St Louis) for this guy and he figures it only costs $15 or 
so to do this to your roof. Scroll down almost to the bottom and find a 
link at the build it solar site of the guy who did this.

Bob Waldrop

-----Original Message----- 
Here is the information I received from David (the person from the blog 
article):

Someone asked me how it affected my electric bills... and i
researched it pretty thoroughly because i kept a lot of electric bill
information for several years back. I figure it saved me about 30
percent of electric USAGE. I did not compare dollar amounts from year
to year because the price of fuel changes. I only compared kilowatt
hours per month used.

Also, many people have emailed me and most people ask the same
question about how well the lime sticks... etc.. so i have simply copy
& pasted one of my emails to another person. This should cover
pretty much everything most people wonder about... here it is:

---------------------------------

STICKING ABILITY: Everyone asks this question.
Yes... lime is called "whitewash" and it will eventually come off.... but it 
sticks a lot better than you might think. It stayed on my roof for 2 
winters here in St. Louis ....(and didn't come off). I suspect it might 
wash off after 4 or 5
years. But the cost is only $15 bucks to cover your whole roof.. If
you are still afraid of it not sticking, just purchase one bag and do a
test painting of a scrap piece of wood.. or paint your dogs house roof. by 
the way, it WILL wash off during the first couple of hours if it
rains before it dries. That's a big consideration in florida! Be sure to 
paint on a non rainy day. (good luck)

SEALANT: Just forget it. This stuff (lime) is not going to seal your roof 
against water leaks at all. But the
ELASTOMERIC coating is not made for shingle roofs either. If your roof
has any leak problems, better look for another solution.

APPLYING: I didn't carry any water up the ladder. I only carried the LIME 
POWDER up the ladder. I dumped a couple gallons
of powder into a big ice-chest on the roof. Then used a water hose
(running slowly at edge of roof) into the ice chest. I Mixed using my
long-handled roller. I just added water until it "looked ok" I wanted
it kind of thick so i didn't have to do 2 coats. You don't want to do
this twice. so mix it kind of thick. My "50--50" statement is only a
rough estimate. Dont over-worry about it. it's not all that
critical....... it just has to have some water in it to get it to act
like paint. I would dump about a gallon of paint at the peak of the roof 
and it would run down while i SLATHERED it around with the roller. This 
makes painting between the shingle-gaps much easier.

DRYING: During painting, you will say, "This stuff
isn't very white!" but just wait untill it DRIES. It will dry a
BRILLIANT white that will amaze you.

MY ROOF: My house has regular shingles on it
again... not white ones. My wife did not like our roof looking
"different" than everyone elses. So I went ahead and replaced the
shingles with standard brown ones. Then winter came... it SNOWED....
and i said to my wife, "Look honey... everyones roof is white now! Its
so pretty, isn't it?" She didn't see the humor in this, nor the
sillyness of dis-liking white roofs.

WAIT 24 HOURS (before applying the paint mix): I
think i read that somewhere also. Maybe that has some validity i don't
know. Maybe it will stick better if you wait 24 hours??? I think it
sticks well enough to just paint it right away.

OTHER IDEAS: One man emailed me and said he was
going to mix his with some CONCRETE powder to help the sticking
ability. That sounds like a good idea to me, but he never let me know
how that went. I have also heard you could mix it with EGG WHITES to
help with stickability. Lots of things a person could experiment with,
but it sticks pretty well all by itself just mixed with water in my
opinion.

CLOTHES: Wear some shoes and clothes you dont want. You will ruin them 
doing this job and will have to throw them away.

SAFETY: Wet paint is slippery. My roof was not
very slanted, but if your roof is very slanty...be carefull you dont
slip and fall.

RESULTS: My attic went from 145 degrees down to
about 100 degrees using this lime paint!! This is MUCH more effective
than installing any kind of attic vents. My attic vents and soffit
vents and FAN POWERED vent only reduced attic temperatures from 145 down to 
about 143 degrees!!!! The effectiveness of this is truly amazing!

THERMOMETER: It is good to document your success.
Purchase a cheap digital thermometer (about $12) with one of them
wired-probes. You can add 10 or 20 feet of wire to the probe to monitor 
your attic temps. Most of them have a MEMORY of todays minimum/maximum 
temperatures you can read... then press "CLEAR" so you can read
tomorrows maximum. Write down your results before and after the
painting. I got my digital thermometer at HarborFreight tools. They
sell them in the garden department of hardware stores also.

BEFORE YOU START: Measure your attic temperatures
to see how hot your attic is getting. If your attic is below 120
degrees, then don't even bother painting the roof. You will not see much 
improvement in house temperature reduction (in my opinion). If your
attic is more than 120 degrees, then you are living in an OVEN or a
BROILER. All that heat is coming down and making your house too hot.

I hope that answers some of your questions. Good
luck on your roof painting project. Feel free to email me if you have
any other questions about it.

Dave Mundy in St. Louis Missouri.

________________________________

On Monday, August 08, 2011 04:51:53 PM Bob Waldrop wrote:
> This is really interesting, I hope you are able to contact the author, I
> didn't notice an email on the page. I'm also wondering, if it does wash
> off, of the consequences for my soil. Reduce acidity I guess. . .

If the slaked lime is high quality, it is pure Ca(OH)2. On the roof it 
reacts
over to lime - CaCO3. It will slowly (over a couple of years) dissolve in 
pure
rain water and end up in the soil as lime. In areas with lightning it will
dissolve in the weak nitric acid from the nitrogen oxides dissolved in the
rainwater and show up in the soil as lime as the nitrates are used by the
plants. In areas with acid rain from sulfur burned in coal, it will rather
quickly dissolve in the rainwater and show up in the soil as gypsum -
CaSO4.2H20.

>
>
> A very intriguing idea....I have a vaulted ceiling that I'd like to better
> insulate against summer heat but haven't due to have to redo
> the insulation / re-sheetrock (unless someone has a better suggestion)..
>
>
> Here is a posting I found that sounds promising:
>
> http://www.builditsolar.com/Projects/Cooling/WhiteRoofExperiment/WhiteRoof.htm
>
> I may contact David to see how the whitewash is holding up a year later.
>
> From: Bob Waldrop <mailto:bwaldrop%40cox.net>
> To: permaculture <mailto:permaculture%40lists.ibiblio.org>
> Sent: Monday, August 8, 2011 2:33 PM
> Subject: [permaculture] Whitewash for roofs?
>
> The energy savings of white roofs appear to be well substantiated. But
> painting your roof can be expensive.
>
> There is however a lower cost way to achieve whiteness and that is
> whitewash. Here’s basic info from wikipedia on the subject.
> http://en.wikipedia..org/wiki/Whitewash . The goal of course would be to
> achieve the energy savings available from white roofs at a lower cost than
> conventional paints, even though it would have to be reapplied every few
> years.
>
> I was wondering if anyone had had any actual experience with this. In
> particular, I’m curious about how whitewash would adhere to asphalt
> shingles. If this would work, it could be a boon to low income communities
> everywhere.
>
> Bob Waldrop, Oklahoma City
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Robert Waldrop, Oklahoma City
http://www.bobwaldrop.net see also http://sharonastyk.com/ 

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