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lekizz
millennium club
Joined: 11 Jan 2006
Posts: 1053
Location: UK
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 Posted: Thu Mar 06, 2008 4:55 pm Post subject: |
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Your plot reminds me of a mountain chalet in Switzerland. I recall reading about this one (or one very similar) where they had to carry some of the larger building elements to the site by helicopter!
http://materialicio.us/2008/01/31/holiday-house-in-the-alps-afgh/
Something like that would certainly survive a hurricane though, like people have said, in your case if the foundations aren't adequate you may wake up in the sea!
Challenging though your site may be, I don't expect for one solitary moment that a college or university would be interested in your project unless, of course, you were paying them for a design service. I expect they can find plenty of sites closer to home to use for student projects.
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birgco
Joined: 01 May 2007
Posts: 302
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| Posted: Thu Mar 06, 2008 5:27 pm Post subject: |
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EngRMP,
There is nothing wrong with bouncing ideas around on this forum.
I think it's a great process but unfortunately you expose
yourself to the naysayers and the doomsday (I told you so) crowd.
With 10 years of planning and thinking about your project, I would say you are more than on the right track.
Good luck and let nuthin nor nobody deter you from your dream.
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EngRMP
Joined: 05 Mar 2008
Posts: 45
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| Posted: Thu Mar 06, 2008 5:36 pm Post subject: |
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OK, as much as I wanted to send photos, it opens a whole new can of worms. But, I really appreciate the interest from this community, so here goes... here is some info about "photos":
- Google Earth (GE) provides wonderful satellite photos, and I can report that the "imagery" is accurate (it is up to date, the amount of vegetation is accurate, the roads are accurate).
- However, for a piece of land this small, satellite elevation data is WAY OFF. I believe that the satellite provides elevation on a 30m sampling grid. The elevation data is pretty accurate, but WAY too coarsely sampled. So, for example, GE shows a house immediate to my SW that is below my property. That is so incorrect. That house is actually 80 ft above my lot, and is at the highest point on this local hill.
- So, I found topozone.com and grabbed a topo map and overlaid that on the property image to provide better elevation data. The attached KMZ files can be opened in GE. One will draw the lot boundaries and the other overlays the topo map. Hopefully you've played with GE enough to know how to toggle the various images on/off. And hopefully you know how to tilt the view angle (in azimuth and elevation) so that you can see how wrong GE represents the elevation.
- Hmmm... I wasn't able to upload KMLs or KMZs to this forum. So, I did a screen grab showing the lot lines, topo map and imagery along with the scale and GPS location. I think that has been attached to this post.
Feel free to correct my reading of the topo lines. I believe that they are 20 ft elevation lines and at the south of the lot, the elevation is about 300 ft. Having visited the lot twice now, I can tell you that the best views are when the house is as far south as possible and somewhat to the west of center. Local zoning laws require the house to be at least 15 ft from the lot lines.
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screen grab from GE
Filesize: 45 KB
Filename: 33 Marienhoj GE.jpg
Viewed: 108 Time(s)
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EngRMP
Joined: 05 Mar 2008
Posts: 45
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| Posted: Thu Mar 06, 2008 5:49 pm Post subject: |
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Thanks Birgco, and everyone else,
I appreciate all points of view. As a research engineer I understand that it is not always simple (for me) to communicate with enough detail and clarity required to provide a full and accurate picture. So, when people reply with ideas and thoughts, I know to heed the advice and consider the possibility of issues; but also to follow up with due diligence until sufficient facts have been uncovered and weighed.
So, again I appreciate people taking the time to consider, and offering their judgement.
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csintexas
millennium club
Joined: 06 Feb 2006
Posts: 1776
Location: USA
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| Posted: Thu Mar 06, 2008 6:32 pm Post subject: |
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Yeah, I have found the elevations in GE to be worthless. It is better to just go to the coordinates in GE and view it. Then you can see better and also the surrounding area.
Well it looks like people are just leveling off areas. Are the other houses built up?
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Chris Stewart
Modern Texas Home Project |
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EngRMP
Joined: 05 Mar 2008
Posts: 45
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| Posted: Thu Mar 06, 2008 7:33 pm Post subject: |
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Obviously the house on my SW is at the top of a hill - so he has a level lot.
The other houses to the west are either cut into the hill, or on stilts.
Birgco, it's interesting to note (now that I look at it with your thoughts in mind) that some of the homes are long and narrow as you suggest.
I'm using Google Sketchup to build a 3D model of the land, using the topo map to define the elevation. It seems to have worked, so I now have a 3D model that I can place a house on and see better how long stilts would have to be.
I'm now playing with an 80 ft long, 20 ft deep notional house plan just to see how it would fit in this 3D model. I can use Sketchup to create the house and place/move it in the 3D land model.
I'm thinking that:
- if I could bring horizontal steel I-beams out from the south road then I'd have the bottom of the house at road level. Maybe vertical steel tubes connect the north end of the I-beams to Earth.
- then I could use those horizontal I-beams to make a large walkway from the road to the house.
- the house only has to be 15 ft from the road. Since all of these roads are cul-de-sacs I don't think I need to worry about excessive noise from traffic that would only be 15 ft away from the house.
- I haven't decided if I want a garage or not. But if so, then I think the I-beam approach should be able to support a car if it can support a house.
- if the house is 15 ft away from the road, and is 20 ft deep, then the north end of the house is 35 ft from the road. It looks to me that the vertical posts would end up being 10-20 ft long.
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mx2
millennium club
Joined: 18 Jan 2006
Posts: 1967
Location: Miami, Florida
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| Posted: Fri Mar 07, 2008 4:33 pm Post subject: |
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I don't think there is a simple choice between column and grid framing versus cut and fill (retaining wall). Regardless of either choice, they each require some serious calculation by a structural engineer to determine the loads on either the pad or the column grid. Structurally it is an equivalent feat. That said, I personally like the house on stilts on the side of a mountain because it respects the lay of the land but simultaneously the house sticks out like a sore thumb. There seems to be a general misunderstanding of the difference between building a very tall (and deep) retaining wall on the surface of the side of a mountain and filling it with dirt (which is ludicrous) as opposed to cut and fill...a common technique of cutting a portion of the slope and using the same dirt to fill the lower portion that is contained by a smaller retaining wall. And yes, the house should be (should) planned length-wise to follow the horizontal plane of the mountain to reduce cost. As opposed to jutting straight out towards the ocean like a big springboard or something. Typically that's why we find winding roads that cut back and forth going up or down a mountain side. I still think you should look into the idea of stepping the house....it can be built in intervals with minimal structural work for each phase...
mx2.5
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*Art of Architecture: The conscious use of skill and creative imagination in the production of an aesthetic building.
*Science of Architecture: The calculated use of technical skill and knowledge in the construction of a functional building. |
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EngRMP
Joined: 05 Mar 2008
Posts: 45
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| Posted: Fri Mar 07, 2008 5:13 pm Post subject: |
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Thanks mx2,
Hmmm... some good ideas that I hadn't considered:
- in my mind the main problem with cutting in to the hill is that with the 15 ft property line set back, the top of the house will be below road level. At this height, much of the ocean view is blocked, and most of the ocean breezes are blocked.
- so, what most people are doing is building 2-3 story buildings. The bottom story is the sistern, then you're allowed 2 stories of living space. I'll be at least 62... my knees already are not what they used to be (don't ever get old)... so, I don't like this approach.
But, I had not considered the house as 2-4 (almost) distinct buildings. They have to be attached (zoning laws); but, they could be at slightly different levels. The top level could be the main living space. If it is separate from the other buildings then the hassle of putting it on stilts to keep it high would be reduced just because it's a smaller structure. If there are only 3-4 steps between buildings then I think it's at least psychologically better than a long stair case.
- so, the immediate question that comes to my mind is: if one building is on stilts (perhaps all 4 corners) and the connecting buildings are hard anchored to Earth, will motion of the stilt-building stress the connections to the anchored buildings? Maybe this is no worse than an 80 ft long building, that is supported at various points, moving in different directions at different points.
- does a house on stilts have to be constructed more rigidly because of motion on stilts. I bring up the motion question because my wife's family has a beach house that is on stilts (telephone poles) to get a view of the Maryland shores. When the clothes dryer runs the spin cycle, the entire house oscillates.
BTW, I understand your point about potential misunderstanding on retaining walls. I see three possibilities:
1) cut partially into the hill and use the waste to continue the slab out from the hill.
2) don't cut into the hill; build a retaining wall and fill it with dirt.
3) cut into the hill the required depth for the slab. (this was my initial thought, but I'd add: build up with waste and additional dirt and incorporate dead-men, etc to stabilize the mass; I thought that if I did this over a 10 year period I'd only be building up a few feet each year. I would have built up 2 ft diameter concrete/etc posts growing 2 feet a year. I'd plant grasses on all surfaces, each year, to stabilize the soil.)
One last item for everyone. I will of course be consulting a licensed engineer before I proceed to building. I might even approach 2 engineers just to see how much the answers vary (which would indicate where the risk areas are). If I can get to an engineer this summer (my next trip) I'll do that - he/she is one more source of info.
BTW, on my next trip, I'm hoping to hire a landscaper or rent a chain saw and cut a path through the property, so that I (and an engineer) can walk the property to assess the steepness at various locations. I'm thinking of about 3-4 switchbacks at the east/west boundary lines for the path. If anyone is looking for an opportunity to visit St Croix, let me know - I might be willing to help out with your expenses in exchange for helping me cut a path.
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djswan
Joined: 17 Aug 2007
Posts: 694
Location: Montana, USA
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| Posted: Fri Mar 07, 2008 7:31 pm Post subject: |
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Hmmmm. Just stab a bunch of bamboo or sticks of somekind for walls floor support or whatever and an old sail for a roof membrane and Bam! you're in.
Hope this helps
Derek
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SDR
millennium club
Joined: 02 Oct 2004
Posts: 1697
Location: San Francisco
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| Posted: Fri Mar 07, 2008 11:14 pm Post subject: |
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I've read what has been suggested so far. Considering all the criteria and conditions, including the owner's preferences, I'd vote for a box (more or less -- the house itself can develop) on stilts, at street level. The owner himself has painted the appropriate picture, I think. What has not been stressed, or even mentioned, is that diagonal bracing of the (steel or wood) posts will produce a rigidly-placed platform, upon which a structure no different from any other can be placed with confidence. This strategy allows the land to drain as it does now. My only question would be whether and how waste can be directed from this platform to a septic system on the slope below.
Thousands of such houses are built in hilly places like the San Francisco Bay area, in and around Los Angeles, etc etc. The post-war housing boom in the latter area saw young architects meeting the challenge of fitting houses to sites like this one, and the braced-frame foundation was replicated over and over. The most desirable sites are the ones which descend from the road; very steep ones sometimes feature a carport as the top level, with the house below, but here we will have the main floor at the level of the road, for the reasons stated.
SDR
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EngRMP
Joined: 05 Mar 2008
Posts: 45
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| Posted: Sat Mar 08, 2008 7:27 am Post subject: |
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Thanks SDR,
- yes, I was thinking that the stilts and posts have to be a "truss" system (I think "truss" is the right term). Diagonal supports in the x any y dimensions to stop lateral movement. I saw an interesting design for a house in San Francisco (I think). The designer used a single vertical post with radial horizontals off of the post. The house was built around the center post (if I remember properly). I forget these details because I was more interested in his analysis that stated that the posts that tie into Earth should be vertical (aligned with gravity) as opposed to perpendicular to the local hill side. His rational was that shear forces would be the same whether the posts were vertical or perpendicular, but gravity is best handled with vertical posts.
- and good point about the septic system. I thought about that when I got my Sketchup model of the lot and a long box house finished the night before last. I realized that the entire house is on stilts (I knew it was going to be this way, but the model shows the lowest part of the house to be about 8 ft above ground - more than I expected). Then I remembered from my initial studies on septic systems (started reading about those last year), that you want VERY slow flow into the septic tank so as not to disturb the chemical/biological mix which is mostly at the top of the liquid. I really don't want a labrynth of plumbing from the house, just to slow down the liguid. So, I think you have to get a sufficient run of nearly horizontal plumbing to slow down the flow. I think that means that I either build a mound above ground to bury the septic tank in (keeps the horizontal plumbing near the surface of the land); or, dig a deep trench to bury horizontal plumbing to reach a septic tank that is buried in the slope of the hill.
- So, if you consult an engineer, are they typically savvy about all of these issues? How about issues like:
- how to bring power into the house,
- how to control rain water flow (I need to collect everything from the roof for drinking, etc; but as I change the land, the water from the hills above me is going to flow differently);
- is the rock in my local area suitable for tieing posts into
- will hurricane winds coming from the north compress and build up the hill to my house; and if so, how do they determine that given the footprint, surface area and weight(?) of the house that I have adequate shoring. I've heard that building codes require all cantilevers to be less than 2 ft because of hurricane winds (that means roof overhangs, etc). I wonder if my house on stilts will be considered "cantilevering".
- is the local cement of adequate quality (given local compounds) for structures. How about for sisterns.
- what materials are suitable for roofing if you're collecting rain water to drink.
So many questions... boy am I glad I have 10 years to try to figure this all out... (what are the chances that there won't be any surprises, even after 10 years). But, this is a great opportunity to learn.
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SDR
millennium club
Joined: 02 Oct 2004
Posts: 1697
Location: San Francisco
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| Posted: Sat Mar 08, 2008 1:18 pm Post subject: |
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Three post-war houses in Los Angeles:
R M Schindler, 1949 -- not one of his loveliest creations
 Craig Ellwood, 1955
John Lautner, Malin house ("Chemosphere"), 1960 -- note ground-view window at lower left. Floor was originally slate.
John Lautner:
"The best solution, structurally, economically, and aesthetically, for this site was to build the house on one central concrete column on one foundation, without disturbing the natural vegetation or drainage. Though the column has a 12 foot diameter footing in the rock for the 60 foot diameter house, the column itself is relatively light, five feet in diameter, with a three foot hollow for the utilities. Because of the weight, an all-concrete construction would not have satisfied earthquake requirements economically. A lighter steel and wood structure was used. The [laminated wood bents] are tied into the central skylight, keeping a clear span roof with no center column, and creating a maximum of livable space. The living and dining areas take up approximately half of the building. The glass is sloped inward to prevent a viewer from looking straight down and getting a feeling of vertigo, accentuating instead the distant horizon. The access to the house is with an electric cable car.
"Leonard Malin, a young aircraft engineer, was fortunately open to new ideas and imaginative designs for the very difficult site.The typical approach to a site like this would have required 10-foot high retaining walls to hold back the entire hillside at astronomical cost. A bulldozed fiat pad lot in this neighborhood at the time cost $30,000, while this lot cost $7,500. The construction of the fioor up in the air cost $15,000.
"Johnny de la Vaux, one of the finest craftsmen in California, built this practically alone, with Leonard Malin assisting. He rigged telephone poles, guy wires, cables, and a winch to place material. A typical contractor would have rented a crane and run the job out of sight in cost. If the architect going into a project does not know the possibilities of construction, then completing anything as unusual as this house would be virtually impossible."
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djswan
Joined: 17 Aug 2007
Posts: 694
Location: Montana, USA
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lekizz
millennium club
Joined: 11 Jan 2006
Posts: 1053
Location: UK
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| Posted: Sat Mar 08, 2008 3:30 pm Post subject: |
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Goodness, the third one looks like my (rather dodgy) 2nd year project on a cliiftop in West Wales 
Is it designed to launch itself in a hurricane?!
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djswan
Joined: 17 Aug 2007
Posts: 694
Location: Montana, USA
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| Posted: Sat Mar 08, 2008 3:52 pm Post subject: |
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Golly gee, You could dig a cave inside your bamboo and old sail house, in case of a hurricane. Call it a cellar or "hurricane cave" Might make a nice place to party in.  Hurrican powered houses? It could be the answer we're all looking for.
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