Cordwood and stone Hobbit Houses

[John_C]

I found myself with a bit too much time on my hands last night and decided to search for personalized icons.  My demented sense of humor took over and I found a bunch that I'll probably use over time but when I found this one

it came from a web site where an inexperienced builder had built an all stone hobbit house in Michigan.   Afew nice pics and he had fun while doing a very nice job.

http://www.daycreek.com/dc/html/tom_huber.htm

(John C. - hope you don't mind, I edited the title for a more searchable thread. JCR)

[glenn kangiser]

Cool site, John.  Everybody loves those crazy hobbits. :-/

[John Raabe]

Most interesting article!

Hey Glenn, aren't hobbits distant cousins of troglodytes?  

The author (Tom Huber), towards the end of the piece, explains the combined stone and interior cordwood wall system that he has evolved. It provides for decent insulation (4" of foam - appreciated in Michigan, I expect  ) with the Hobbit materials he loves - cordwood on the interior and large scale stonework on the exterior.



Note: the house above is not a cordwood house nor an example of Tom's wall project. (But it is a great Hobbit house! ). This house was built by Earl Young as discussed in the Daycreek forum.

Back to a cordwood and stone wall - I have tried to come up with a sketch of how this might actually be built.



After drawing this I can see that the insulation in this wall is short circuited by the foundation stone work (wavy heat flow line near floor). This can be solved by raising the interior floor up so that the slab insulation aligns with the 4" wall insulation. No doubt the author has some other ideas that have evolved beyond this, but it is a start.

PS - Daycreek.com has a forum on cordwood construction, where I posted a link back to this topic - we may get some input from some of their experts.  

PPS - We had a lot of interest on the old forum in hobbit houses (about the time of the first Tolkien movie). Alas, I think most of those links can only be found on the wayback machine.

[John_C]

And not DIY either  


Long before the was a movie I thought Bilbo's place sounded cool; not to mention energy efficient and sustainable, words that weren't in the lexicon back then.  When I saw the movie I thought it would be a very nice place to live given a bit more headroom.   Glen's place is probably the closest I know of, except for the one I stumble across on the internet.

[thuber]

Hi,

Here is my reply to John C. and John Raabe regarding comments/questions about hobbit house construction involving stone and cordwood masonry (per daycreek.com posting).  You have a great building thing going on over here!

Tom Huber

Hi Richard (and John and others),

I think we have had this cordwood/stone insulation conversation on more than a few occasions.  I was actually trying to find these talks in my saved email folder, but must have misfiled them when I left Michigan for the Adirondacks.

As has been already corrected - the photo of the stone hobbit house is an example of the fine architectural work of Earl Young who built 29 stone homes in the northwest corner of the lower peninsula of Michigan.  His work with boulders (combined with Tolkien's and many cordwood visionaries) was the inspiration for my own efforts at marrying stone and cordwood in homestead design and construction.  Bringing the log-ends up above grade by incorporating two feet of insulated stone work also helps preserve the integrity of the cordwood portion of the walls.

Behind the stone portion of the wall is 4" of rigid polystyrene foam, which should be extended below grade by 2 feet or more (at least 2'' of rigid foam).  I have used this approach with a rubble trench foundation currently here in the Adirondacks where the temps can drop to -30.  The frost protected shallow foundation approach can also work, but as John Raabe sketches out you need to have a thermal break of the stonework both below and above grade otherwise the stone will "conduct the cold" sort of speak.

On the inside of the stone portion of the wall against the foam board, I faced short log-ends and tied in the wall much like John's drawing.  I believe my log-ends were approximately 7 inches long and I was careful that they were dry and that no excessive moisture was placed against the foam (my mortar mix was drier than normal).  One has to be careful that any moisture can travel out the log-ends, since it surely will not travel through the foam!

Once the log-ends came out to the height of the foam panels (2' above grade), longer 16" log-ends were used to bridge across the foam and the stone portion of the wall.  What you end up doing is putting larger stones at the bottom and lean them to the foam so that the wall is not as thick at the top of the two foot section, and thus able to be capped by 16" log-end just above the foam and then log-ends are used to finish up the rest of the wall to the top plate.  It is much easier to position log-ends higher up the wall than boulders.

I guess you could face the entire foam-insulated stone wall with cordwood (see John Raabe's sketch), but I don't think I would recommend it for a few reasons.  First of all, the two materials work together well as delineated above.  Cordwood (and paper-enhanced mortar matrix) provides the insulation for most of the wall that stone does not, and you don't have to purchase the pricey foam insulation (even though I generally think you get your money's worth).  They are even more beautiful used in combination (at least I think so).  Most importantly, I think the risk of facing cordwood to the foam (especially if one uses a paper enhanced mortar) in preventing any moisture from migrating out of the wall.  Short log-ends would help in this respect (kind of like Richard's cordwood siding idea), but unless a lot of masonry ties are used the internal wall may not be very stable.  Seven inches was long enough to be stable but short enough to breathe moisture on the inside and be bridged by 16" log-ends (7" log-ends + 4" foam + 5" stone - which is thinner at top of 2' portion).

For the record, many of the stone homes that Earl Young built in northern Michigan were solid stone (no insulation at all).  They were pretty cold to live in until you charged the walls with wood-fired radiant heat.  I understand the little hobbit house is up for sale again.  Last time, the 800 sq. ft. structure was listed for $380,000 - that's high even for the Adirondacks (where all the rich and famous from NYC want a second or third home).  You could put stone on both sides with foam sandwiched in between if you want 2-3' thickwalls, but you give up a lot of living space in small houses.  

I think the modern day hobbit house uses insulated concrete forms (ICFs) for the portions which are earth-sheltered (you can even use them in the roof), and insulated stone/cordwood and lots of glazing in the south wall.  As I have written elsewhere, I believe Tolkien intended the passive solar hobbit hole.

For any of you hobbit-lovers out there, a new book was just released entitled Ents, Elves, and Eriador:  The Environmental Vision of J.R.R. Tolkien.  It is rather scholarly in places, but does capture the agrarian spirit of the hobbits quite well.  Might want to request it through Inter-library loan.

With the great thanksgiving feast on the way - cheers to all!

Tom

[John Raabe]

I will also add the follow up post I made at the daycreek site:

Tom:

Thank you very much for your thoughtful description of your designs and construction techniques. I think your insulated stone foundation in combination with an above grade 16" cordwood wall is both a long lasting functional solution and a handsome interpretation of a "hobbitesque" building system.

Such a wall would likely have an R-16 to R-18 (continuous) insulation value - about equal to a framed 2x6 wall with R-19 or R-21 fiberglass insulation.

Much, much better than a true stone wall!  

For the full height stonewall I was sketching in my diagram, I expect the ICF structural wall with stone facing that you mention is probably a better choice... and easier to do in permitted areas as the structural racking resistance of the wall I diagram would be difficult to determine and is likely to be too low for earthquake areas.

[glenn kangiser]

Very interesting, Tom.  Thank you.

[desdawg]

I have thought about doing something with cordwood and still may at some time. It is pretty labor intensive construction I believe. I have access to lots of small trees in the mountains that wouldn't be suitable for conventional log home construction. I need to have a lot less on my plate before I tackle that though, given the time committment involved. I did order a Norwood mill to see what I can do to make some lumber out of some of that stuff. The trees are thick and the dead or dying ones will become termite fodder when they hit the ground. And the healthy trees will do better if some thinning occurs. I hate seeing good trees, even smallish ones  become mulch. And I love playing with my chainsaws.   Here we go again, down yet another path.

[glenn kangiser]

A friend of mine once told me "When you have a sawmill, you never look a trees the same way."  

You are always thinking - hey, I could get a lot of boards out of that.

[John Raabe]

The first cordwood project I ever saw was at an Energy Expo in Vancouver, BC in the early 80's. It was an interesting low-tech building system but had problems with shrinkage and air tightness. Modern mortar additives and caulking materials may have solved some of those issues.

Cordwood has always been handsome.

Like any of the other stacked wall systems (strawbale, stone, adobe, log, tires, etc.) cordwood faces stability concerns in high wind and earthquake areas. Braced timber framing or plywood sheathed stud wall sections can stabilize the walls but complicate and compromise the intent of the project.

Still, there are lots of places where a great cordwood structure could be built at relatively low cost and would last hundreds of years with proper maintenance.

• Here is MORE information from Daycreek.
• An article on the Return of the Cordwood House, from Mother Earth News.
• A link to the Rob Roy book on his cordwood construction system.

For a fun follow-up to the romance of Hobbit Houses



Click THIS LINK to explore the "Mushroom House" a 22+ year building project by an artist working in the mountains of British Columbia.

[desdawg]

Thanks for those links John. I will have to spend some time reading now. I was thinking of post and beam framework with cordwood infill but then I haven't done all of that reading yet. Maybe I will see something to change my mind. Or maybe I will become more convinced that is the way to do it. We shall see.

[timby]

Folks

While you're looking at unique buildings you may want to look at the following site:

http://photos.itsa.info/thumbnails.php?album=14

This is an underground thin shell concrete dome built to look like Bagend.

Later
Tim

[Amanda_931]

Hmmm--Bag End II looks so, well, like it was made out of manufactured "tiles" and culverts and domes.  I wonder what's happened to in in the last couple of years--nothing on the site after 2004.

It's in Tennessee, but I'd guess that the "big city" is Asheville NC.

[Sassy]

Thanks for posting that, John,  just loved looking at the Mushroom House - especially the spa/sauna & kitchen - very creative & beautiful.  

[desdawg]

Guess I will be doing some reading. I ordered Cordwood Building: The State of the Art (Natural Building Series) and Building with Stone since I have so much natural stone available at my site. These are a couple of things that I have had in the back of my mind for a while now. The problem is: TIME. Almost as valuable as MONEY.
Once again John, thanks for the links. I need more projects. I will have to live to be 100 just to finish the ones I already have started. You just extended my lifespan by at least ten years.  

[Amanda_931]

I know that feeling desdawg



Currently I'm kind of stuck trying to keep busy--and it's been cold in the mornings.  At least partly because I have an enthusiastic helper who really wants to work.  

[desdawg]

Amanda, I love to read. And I love to build things. I guess I just have to sample a little of every type of construction before I wind it down. And I really like putting something together for pennies on the dollar compared to what other people would spend for something similar. So my native materials, auction found materials, scrounged materials all play into the formula. I have been pretty successful at it so far and "if it ain't broke, don't fix it". I have fun with it.

[glenn kangiser]

Rob Roy's book tells how to make insulation from lime and sawdust - it insulates the center section between the inside and outside mortar to stop air leaks and give a higher R-value.  Cordwood was one of the early alternatives I considered - may still do some of it.

desdawg, I think we would probably have fun playing sandbox if we ever had the chance to get together.  You think like I do.  Poor fella. :-/

On the cordwood and rock combo, I would probably have to substitute pieces of barbwire for the ties as I am not allowed to buy conventional materials - same standard as you desdawg. Bargain, salvage or free.

[desdawg]

I knew we were kindred spirits Glenn. I guess we don't actually have to meet, we can swap ideas (and lies) on this fantastic forum. Thank you for the forum John. Someday I may make it to Mariposa, CA who knows. You will laugh, but I live in Maricopa, AZ. Well, not in it but I have a Maricopa mailing address. Go figure.

[glenn kangiser]

Once in another life I hauled a load of something through Maricopa, desdawg.  I don't recall Sheriff Joe chasing me there though.  http://en.wikipedia.org/wiki/Joe_Arpaio  :-/

[desdawg]

That is one of those little confusing things the gegraphers amongst us do to baffle people. Joe Arpaio is the Maricopa County Sheriff. The City of Maricopa is in Pinal County.
Kind of like being in Wyoming. Cheyenne is the County seat of Laramie County. Laramie Wyoming is not in Laramie County.   :-/>

[jwv]

Oh gawd! I come here and have to hear about Joe Arpaio!   There's a PT Barnum for every generation!

Judy

[glenn kangiser]

....but , Judy, --- I was so hoping to get some of those pink tights he passes out if I ever got on one of his chain gangs.

[desdawg]

If you come to Phoenix and you are living just right you can qualify for pink undies. They come complete with a baloney sandwich in a brown paper bag.... and on a good day you get an apple thrown in.

[glenn kangiser]

Just about every town and city around here has a few to a lot of guys who would look good in one of those outfits and enjoying that fine brown bag lunch. :-/