[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
GSBN:(LONG, multi-responses) Re: TLS #38, Roofs & Foundations
- To: "GSBN" GSBN@...
- Subject: GSBN:(LONG, multi-responses) Re: TLS #38, Roofs & Foundations
- From: Mark Piepkorn duckchow@...
- Date: Sun, 24 Feb 2002 17:07:04 -0500
- Reply-to: "GSBN" GSBN@...
- Sender: "GSBN" GSBN@...
<x-flowed iso-8859-1>At 11:50 PM 2/13/02, you posted:
>I'm hoping I can enlist some of you for direction,
>advice and material...
>I'm looking for:...
>Ready to be stunned by your responses...
At 10:40 AM 2/20/02, you accidentally posted:
>To date it's netted exactly zero response!
Joyce said that she liked the detail of your post; here's a friendly
opposing viewpoint from my experience:
Though it's always a crap shoot, something I learned when I was on the
CREST list, and which was reproved when I was editor at TLS, is that the
wonderfully thoughtful people of SB (like most wonderfully thoughtful
people anywhere) almost never respond well to requests for the very
general, nor for the very specific. On the one hand, imprecision opens the
door to a universe of discourse in which almost nobody want to get mired
(and those that do get tiresome quickly)... and on the other hand, the very
precise leaves almost no wiggle room for people to obliquely fit in their
own related experiences.
Personally, I can respond to almost nothing on the list you posted. Most
of it's too specific. Finding targets for those darts will take a lot more
concentrated effort than a wideband broadcast, even in such a select and
august group as that gathered on the GSBN.
You wrote, "I don't think there's any way to do this job but to approach
people individually, with an assignment already in mind." Some of the best
articles in my time came in completely unsolicited, and others from general
calls for submissions. But what you said is also true, especially in light
of the list you presented. In my experience, approaching people one-on-one
with a somewhat tight (but not completely firm) idea about a topic you know
that they know about worked most consistently in getting articles. Which,
to avoid hitting up the same people over and over (which gets annoying for
them and for the readers) means keeping on top of news and gossip.
Being subscribed to and actually reading not just the CREST list, but the
regional lists and Euro lists and Aussie list and other nonSB lists
(cordwood, earthship, cob, etc). Reading magazines. Developing
relationships with people, not just thinking of them as sources... keeping
in mind that first and foremost, they're *people*, and as such they're
unique and interesting and multifaceted and they're about WAY more than SB.
Imagine what it's like to be one of the "important" folks who are
constantly badgered by people wanting things from them. Imagine that the
only time they ever hear from TLS is if TLS wants something from them. I
know how I'd feel. Sometimes people like to know that their value as an
individual extends beyond what they can do for whoever happens to be on the
other end of the email or phone or handshake.
The situation reminds me of something. A few years ago, a couple guys in
Canada sent out some excited emails - they had a big barn at their disposal
and were going to do some SB experiments in it. I replied, asking if they'd
keep me informed about what they were up to. Never got a reply. A couple
months later, I sent an email asking how things were going. No response. A
few months more pass, and I asked again. Then I gave up. Later, these guys
decided to write a book, and sent another email around asking for
submissions. Remembering how I'd been treated by these people, I chose not
to respond. Usually, our futures are written by our own hands.
Anyway, that's what I think, not that you want or need to hear it.
At 11:50 PM 2/13/02, you wrote:
>I'm looking for:
>-insulation options, including thoughts on bales as roof insulation
There's a place in Maryland that used shredded blue jeans for roof
insulation; available commercially, I don't remember the name of the
product. Pics at http://www.potkettleblack.com/misc/williams.html , contact
the owners from there.
I also recall at least one party using raw wool purchased from the Navajo
Nation, but don't remember any details. Rob Tom might.
Bales as roof insulation, my thoughts. They need to be sealed on all sides
with wet-applied plaster. Talk to Kelly Lerner, one of her Mongolia
projects had bales in the ceiling which caught fire. Cost-benefit analysis
of beefing up the structure to accommodate the extra weight vs using
lighter-weight conventional insulation needs to be considered.
>-leads on good people to talk to about living roofs, thatch, slate,
>and other traditional roofing systems
Living roofs are addressed at length below.
Thatch, do a search at http://www.google.com on the phrase (using
quotation marks) "master thatch."
Slate, get with Joe Jenkins if you can. http://www.jenkinspublishing.com
>-thoughts on the aesthetics of roof design
Contact Ann Edminster. Use the phrase, "fussy, anachronistic roof lines"
and tell her I sent you. Get a copy of her book Efficient Wood Use In
Residential Construction, available from the NRDC. Balance the isolated
consideration of aesthetics with environmental and pragmatic concerns.
OK, now I'll get general. I'll just start riffing. (I don't really have
the time or desire to research and write an article myself. Though I'm
willing to do reviews in exchange for a copy of the thing reviewed, mostly
because I enjoy writing reviews. Well, maybe I'll co-author something if
somebody else takes the lead.)
Most interesting roof thing I've seen lately was Sam Droege's
"out"sulation method... see pics at
http://www.potkettleblack.com/misc/sam1.html ... I think he'd be quite
helpful in providing good details, just drop him an email from the pics
pages. Actually, thinking about it now, it's a lot like the insulated
earthship roofs (which are nothing more than living roofs, really), but
without the dirt. Could incorporate that angle, too. (Just don't use the
first earthship book as a reference - the thing has enormous, horrible
flaws in it.)
You could sic somebody on the relative ecological-vs-practical merits of
various roof cladding options. I'm told that Ondura, f'rinstance, is
significantly comprised of recycled content - but how's it last? Can you
catch rainwater on it? There was a recycled-content fibrous-cement shingle
on the market a while back that got pulled because it reacted adversely to
water. Just what you want in a shingle, right? (Details in some old EBN
Could get with Shay Salomon, too, if you wanted, who's used metal printing
plates to roof a couple vault projects.
Pat Newberry made his temporary-quarters roof out of cement-soaked carpet
(while he's been building his weird SB/earthbag hybrid, previously in TLS).
There was a tire-roofing article from Matts a while back.
Could have somebody review appropriate chapters of books like The
Owner-Built Home for other homebrew options.
The Steens have tried various things in Mexico, nearly all of which I've
Does the book A Pattern Language have anything interesting to say about
roofs? How about the Canadian Home Builder's Guide?
Catherine's given presentations about living roofs at the last two Build
Here Now events. You might do a little 'net search for other people too -
there's at least one company out there specializing in living roofs, and I
recall that they had a decent website. I visited a SB place under
construction in PA that hired them and was satisfied, but it was a short
visit and I didn't have my camera. I also seem to recall reading that one
of them big cities in Switzerland (was it Stockholm?) passed legislation
that all new roofs, or roofs being repaired, were required to be made into
living roofs. The first code-approved SB house in Minnesota had a partial
living roof; someone could contact them or their architect to see how it's
holding up over time. Their contact info should be in the second Moisture
issue, I think, and they were previously a Regional Rumbling. (Note that
the area code may have changed since then - unless you call their
architect, Jono, who was in Minneapolis.) Rob Roy has always done living
roofs; could cite his books, or contact him for an interview.
Oh, and there's the fascinating reciprocal roof; there's a SB place in
England with one, and I think John Glassford's done one, and Robert Andrews
( http://www.balewatch.com ) could be a good contact about it. See some
pics at http://www.strawhomes.com/build/here/now2000/tour/10.html
But this is probably mostly too hippie-dippie. For the pro/normal end of
the spectrum, somebody could research the general topic in EBN, JLC, even
FHB and like-that.
Could discuss the merits and drawbacks of various truss designs vs
rafter/ridge-beam affairs. (I like scissor trusses, though dropped-heel
trusses are OK... but the rafter/ridge-beam approach will always be nearest
I think you should definitely do something in no uncertain terms on flat
roofs, they're ?ü¢kïng pernicious for SB, always have been and always will
be, and people STILL want them. Talk with Jeff Ruppert, and see if DE and
Matts can discuss their expert-witness dark secrets yet. There are old
turn-of-the-century photos from New Mexico pueblos that can be dredged
up... they show flat roofs, yes - but flat roofs with OVERHANGS. (And
again, adobe ain't SB.) People get so wrapped up in that evil "southwest"
look. Oh, that's another thing on this topic: research the *actual* origins
of "Santa Fe Style." It was self-consciously derived, based on *pieces* of
reality which were sometimes taken out of context. A few months ago, the
Smithsonian Museum of American History had (maybe they still do) an exhibit
about New Mexico, which had a presentation about the area's architecture; a
sign in that presentation read, in large type: "To give Santa Fe the look
that tourists expected to see, the city planning board in 1912 asked a
group of archaeologists and artists to define a Santa Fe style. The group,
which included archaeologist Jesse Nusbaum and anthropologist Edgar Hewett,
urged that all new buildings near the old plaza have flat roofs, protruding
roof beams, and adobe like surfaces. One observer noted that 'Santa Fe was
a place fast becoming what it should have been.'"
Pertinent to roof concerns, here's an email I answered recently -
additional/opposing viewpoints could be solicited:
At 10:55 AM 2/12/02, Patrick Geile jonene@... wrote:
>I have a question concerning the application of
>stucco between the two base plates on the top
>where the joists fit. Is it necessary to apply
>stucco between these two base plates? This
>is where the rafters attach and it is difficult to
>apply stucco up there.
There's plenty of people who wouldn't and haven't. I'm not one of them.
A Couple Reasons To Do It
1) To create a complete air barrier. It's been shown that the
stucco/plaster/render is a very important part of the thermal resistance of
the wall system. If there's an air gap between the straw and stucco (which
could potentially develop during or after application), computer modeling
has shown that the R value can be decreased by up to half due to convective
loops. Following that logic, if the top of the wall isn't sealed - whether
or not there's an air gap between the bales and finish - it could act like
a chimney, and not perform to its thermal optimum.
2) To keep out buggies and beasties. It's often said that critters don't
like nesting in bales because the bales are inconveniently tight. That's
basically true - but the generally unsaid part is that it's not *always*
true. Particularly if there are less-dense cracks between stacked bales
(since critters are usually just as happy to follow the path of least
resistance as we are).
I visited a SB house in Colorado that had a rats-in-the-wall problem. In
that case they came up from below on the outside of the house, tunneling
along the seams between bales, finally hollowing out a nest at about eye
level. That house had a too-low stemwall that only brought the bales above
ground level six inches or so; and this stemwall wasn't as wide as the
bales, so the bales cantilevered over it three or four inches. The stucco
was applied as you might suspect: leaving a three- to four-inch gap which
opened directly to the bottom of the bales.
That said, the sealer doesn't have to be cement stucco. It could be an
earthen plaster from the site.
Since you're foresightful enough to ask about this, I think it's probably
safe for me to assume that you're going to detail to prevent condensation
or leakage from dripping onto the top of the wall.
You could do something about basements vs not-basements... y'know, the
traditional full foundation with basement compared to something like FPSF
or even pier. Sara Mock of http://www.moxvox.com is fully in favor of
basements (though she seems to particularly mean walk-out basements), where
other people (Ken Kern was one, as I recall) are dead against them as
foolish and pointless and little-used and needlessly expensive. Does it
cost more to add sf by going down or up? That's first-cost, of course...
what about life-cycle costs? It can be easier to heat those extra sf if
they're in a basement, but at the same time basements can be a potentially
significant contributor to heat loss. But in a milder climate with wide
diurnal temperature swings, earth-coupled basement-like areas can be
utilized to excellent effect. Stuff like that. Which leads into discussions
of theories like John Hait's book Passive Annual Heat Storage, which I know
by reputation only but seems to contradict the excellent research done by
the Underground Space Center of the University of Minnesota (defunct).
Could do something on self-draining foundations, an old-Europe thing. Go
to the Amazon Nails website and download the terrific pdf document Guide To
Straw Bale Building and check out the section on foundations for this (and
other low-tech thoughts). You could ask Barbara to expound. But it can also
raise some questions: What about air movement? What about ingress and
egress into the bales for little nasties - or big ones, depending on the
design? (Flashback to the house with the rat problem described earlier.) In
drainage practice, what's the big difference between a self-draining
foundation and a typical 'Murrican-bale toe-up detail that incorporates a
What's better: A typical FSPS scheme where the insulation is employed in a
horizontal skirting - or where the insulation goes vertically straight down
into the ground (like basement walls), isolating the earth/mass directly
below the footprint? How climate-dependant is the performance of each option?
Could revisit ways to avoid the "superwide footing" that so many people
*still* seem to assume is required for SB construction.
Could talk about cantilevering, which isn't really foundations but is
usually low to the ground and could be introduced by way of a discussion of
pier foundations. I know of a place in West Virginia (pirated without
permit, and as secret at the owner's request) that's built with a pole
frame, and the bale walls are outside the poles on cantilevering plates and
joists. Which leads to questions about the best way to insulate the joisted
Do followups on people who have done unusual foundation things as reported
in previous issues of TLS. Contact 'em, see how it's going, and if they'd
do it again.
There was some sort of ruling recently in the US about some stuff used to
treat wood. Don't know what it was. But it opens the door to a discussion
of permanent wood foundations. I think there's a booklet from CMHC on the
subject. (I think CMHC has something on EVERYTHING.) Research for an
article on this topic could include the book The $50 And Up Underground
House, which details ways to waterproof UNtreated wood-framed *underground*
structures. I've been to a place in Minnesota a couple times that was built
this way well over a decade ago, and it's outstanding and gorgeous and I
feel completely safe inside it. No evidence of moisture intrusion ever,
anywhere. See pics at http://www.strawbalecentral.com/lilac/lilac2.html
Go to http://www.google.com and type in (with quotes) "alternative
At 12:29 AM 2/22/02, Joyce wrote to Chris:
>Could you let me know more about the non-GSBN interest
>and offers you are receiving - maybe forwarding them to me
>so I get an idea of who and what and when.
As things concern TLS, I think each staffer (and I think of everyone as a
staffer - NO hierarchy) should always know what the other is up to -
*especially* if one of them thinks that it's none of the other person's
business. Because that usually means that there's an ego getting freaky.
IMO, *all* TLS email should go through the TLS email address. Bill C
should be able to set it up like a miniature email list which resends
incoming mail back to each staff member. This relies on each staff member
either setting up their email program with a TLS "personality" that has the
return-address field filled in with the TLS email address (so when people
hit the reply-to button the response goes to the TLS email address), or
setting up a personal TLS-only email account in the same way through one of
the free services, like Hotmail or Yahoo.
GSBN isn't really the best venue for it, IMO... snicker...
At 07:04 PM 2/22/02, Joyce wrote:
>They are watching us and talking to each other about us
I think this accidental series of posts has been more funny than anything.
If anybody's judging you harshly as a result, I hope it remains *their*
problem and not something that gets hung around the neck of TLS. What I've
seen is a couple people trying VERY hard to uphold (and, if possible,
improve) the legacy that is TLS. The only thing I haven't really cared to
read was the idea of being manipulated toward some hidden goal... but I
have to admit having done the very same thing in the past on the CREST
list. (I'm still too awed by the people on GSBN - probably always will be -
to try to pull anything over on them.)
At 01:44 PM 2/22/02, you wrote:
>I have seen several living roofs go on bale buildings here
>in Ontario, and I'm dubious about their value from an
>environmental point of view. Anybody have thoughts, ideas
>or suggestions for a well-balanced article on living roofs?
>Otherwise, my article will end up with a slightly negative
>tone, based on what I've seen installed.
When a building is built, what was (usually) previously a patch of
CO2-munching greenery becomes a patch of composite shingles or steel
roofing or some other nonliving surface. And that doesn't include trees and
other vegetation cleared to make yards and swimming pools and driveways and
parking lots. Bale walls are carbon sinks, but the bale walls won't last
forever and eventually that carbon will be released. In the meantime, a
living roof can be working to offset that eventuality, as well as the
emissions included in the overall embodied energy of the structure.
Potentially, if it became a common practice, it seems that green roofs
could be a sizable part of the step toward housing that actually
contributes something back to the physical environment... as well as the
Along both of those lines, gandering at a copy of Malcolm Wells' book
Recovering America might prove illuminating.
I ain't got numbers, so I don't know what the EE and other
non-building-performance tradeoffs actually are. (It would, of course, vary
enormously one example to another.) The frame will typically need beefing
up to accommodate the extra load. In desert climates, people might end up
wanting to water the roof like they water their unnatural lawns, and that
would be a stupid thing to do in the face of shrinking aquifers - though it
would increase the performance of the roof for reducing cooling loads. And
I don't know how much C02 can be converted to 02 by green roofs of varying
sizes and plant types. So you're right, I'm just yappin'. (Which is a
cop-out say of saying that the variables are tremendous and need to be
considered on a case-by-case basis, which is why it bugs me to no end when
I read articles that are climate-centric and otherwise not encompassing...
locally-derived opinion - and subjective to boot - disguised as universal
As for how they perform, a typical uninsulated living roof in a severely
cold climate is almost pointless in terms of any benefit of thermal
resistance. A typical living roof should be as well-insulated as a
The book Earth Sheltered Housing Design published by the Underground Space
Center of the University of Minnesota in '78 has a wealth of data about
this stuff, particularly with regard to the widely-disparate seasonal
climate(s) of Minnesota. Cutting through the numbers, it notes, "...in
order to compete effectively with standard insulating materials, soil
depths in excess of 2.75m (9 ft) would be required on the roof." That
speaks specifically to a climate like Minnesota's; less depth would be
required in milder climates to achieve the same results.
Nine FEET of dirt? Yikes. An insulated compromise version with comparable
thermal resistance would have 10cm (3.9 in) of polystyrene insulation
covered by 46 cm (18 in) of earth. Both are equivalent to 12 cm (4.6 in) of
polystyrene and no earth cover. (Here we might remember Sam Droege's
"out"sulation that I mentioned earlier. He used 9"-thick foam sheets that
he got from a supplier to SIPs manufacturers.)
The difference between the performance of these models (which didn't
consider any greenery, just the earth cover) all have to do with mass. Just
like the fabled thinly-distributed high mass of SB helps moderate
temperature swings, thereby reducing space-conditioning requirements, so
too does the mass of the earth on a living roof moderate things.
A comparison of performance in Minnesota-January weather was made between
an 18"-earth/4"-polystyrene roof ("Roof A") and a no-earth/4.6"-polystyrene
roof ("Roof B"). Each had the same level of thermal resistance, and both
were supported by concrete planking. The model weather outside was -12C,
followed by a cold front where the temperature went down to -18C for five
days, after which it went back up to -12C.
Quoting the book:
"Due to its low thermal mass, Roof B responds immediately to the change
outside and within two days reaches a new maximum heat loss which is
maintained for the remaining three days. When the temperature returns to
normal, Roof B responds at once and after two days has returned to its
normal January operating level. Roof A, however, requires a full day before
the ceiling begins to indicate that more severe conditions now exist
outside and once it does begin to respond, does so much more slowly than
Roof B. After five days, when the outside temperatures return to normal,
the heat loss of Roof A is still gradually rising having attained only 77%
of the increase of Roof B. Roof A requires another full day before
responding to the return of normal weather conditions.
"...despite the much longer total response time, Roof A require 8% less
total energy than Roof B to cope with the severe period. At the same time,
Roof A exhibited a peak increase in load which was only 85% of that of Roof
B. Furthermore, Roof B's low thermal mass required almost twice as much
additional energy (196%) during the five-day period in which outside air
temperature were most severe, thereby placing the bulk of its demand during
the period when the outside to inside air temperature differential was at
its greatest and required the most energy input from the furnace to bring
ventilation air up to room temperature."
The R-value for these assemblies is given as "R=4.35 m2K/W" which I don't
remember how to translate and I don't have the references with me that I
need to look it up.
The text does not directly address moisture content; but if the soil is
saturated, it will be much more conductive than if it's dry. In the book's
appendices, it's suggested that the calculations were based on "very dry"
soil. Also in the appendices: "In studying a single case with moisture
contents ranging from 18% to 37%... it was found that the winter heat loss
was increased by 28%, while the summer cooling rate increased 49% for the
wet soil as opposed to the dry. While such variations show little impact
upon the general conclusions with respect to the advantages of earth
sheltered housing to conventional housing, they do emphasize the impact the
moisture content has on the thermal characteristics of the soil."
Almost glossed over in the book are the summertime benefits of a living
roof. "A final consideration which comes to light in determining the
thermal value of earth cover on a roof is that of the boundary condition
which exists at the upper surface of the roof. Vegetation on this surface
can contribute to the thermal efficiency in a number of ways, such as
shading effects, improved insulation due to air trapped in the foliage, and
more important the elimination of solar heat gain to the roof during the
It goes on to cite a study in which temperatures beneath asphalt surfaces
were found to be over 140F while the air temperature was no more than
90F... and at the same time, temperatures under grass cover were
consistently up to 7F below ambient, depending on the length of the grass.
What's any of it mean? That it's like anything else. A person's gotta
research what's right for their own situation. Sometimes a
properly-implemented living roof will provide reasonable thermal benefit,
and sometimes it just won't be much better than other approaches. There are
situations where the pragmatic trade-offs might favor *not* having a living
roof. But it's about more than just thermal performance.
I mean, what's uglier than looking at your neighbor's decrepit
composite-shingle roof with its curling corners?