Article - Building on a difficult terrain

Started by abraun, December 13, 2007, 03:49:30 AM

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Adjusting the house to the landscape is the first task to be solved when building on difficult terrain. If your block of land has slopes up to 20% - it's rather regular terrain. The difficulties start to appear on slopes that are steeper than that.

Main problems can be divided into 3 categories:

1)   Some additional research to determine the danger of soil slipping down should be done
2)   The foundations and plumbing will require some additional work
3)   Some additional work to level the soil might be necessary

And of course any of above translates into additional expenses.

If the allotment is in a real danger of soil slip, for example the soil has a steep rocky slope underneath and gets lots of rainfall or has ground water - it makes no sense to build on it.

However, if that's not the case, then building on steep slope might produce very interesting outcome. History has many examples of people, who had to deal with difficult conditions, created the most magnificent structures, some of which we can still see in these days. They include the Machu Picchu city in Peru, great castles of Europe, Svan's watchtowers in high mountains of Georgia, and fort Metsada in Israel.

To make the idea of building on difficult terrain a reality, several things need to fall together:

1)   The wish to build on this particular block of land and the ability to finance the process
2)   A talented architect and engineer who can fit the house into the relief while making it secure, safe and sound
3)   Qualified builders who can implement everything according to the plans

So what are the advantages of building on a slope? First, nothing compares to the panoramic view from your terrace. Also, it is possible to create several levels: the garage on the upper level, the bedrooms and living areas below and the back yard and garden on the lowest level. The best thing about this setting is that the road and the driveway – with all the noise and the dust – are left on top, while the house is located below. More of the house is now exposed to the sun light. The garden can have many picturesque features such as little terraces, steps, miniature walls, cozy spots.

The whole presence of the house is improved, as this unique facade is created. The interior of the house benefit from larger windows and various open staircases, they look "weightless" and mix in harmony with the nature.

Another issue to address is the soundness of the house built on a slope. In many ways it depends on the soil underneath the foundations. If the soil is mostly sand or mud, then it makes sense to create terraced foundations, made of concrete bands and retaining walls, anchored in the soil.

If the foundations are to be built on rocks, concrete piles are better. The necessary diameter of a pile for 2 -3 level house is 35 - 40 cm, the depth is 8 to 10 meters. A reinforcing cage is installed in the borehole, which is later filled with concrete. The maximal load is to be defined by the engineer. All of the above methods are intended for brick and concrete houses. The foundations are much simpler to make for lighter houses.

Steep slopes are not the only kind of difficult terrain. One of the world-famous masterpieces - Frank Lloyd Wright's "Fallingwater" - is a house built on top of a cliff with a waterfall rushing underneath. Its multilevel terraces are floating above the waterfall in the air filled with freshness of a creek. Buildings that are so much in harmony with the nature around are usually well-planned and well-built ones.

Another example of such building is the famous Sydney Opera house – a caravel with wind-filled sails in the open ocean. However, the story of those sails has no happy ending: the author of the project that won a contest, architect Jorn Utzon, originally intended for the construction to look similar to wind-filled sails. Unfortunately, the calculations and the construction couldn't be done according his project, which is why the current looks of the Opera House, is very different from the way it meant to be.
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glenn kangiser

Thanks for the article, Anthony.  Welcome to the forum
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin

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John Raabe


Thanks for the thoughts on the advantages and challenges of building on a slope. It's a good overview of the process and the extra effort and expense can often add a dramatic element to the design.

Occasionally, when the site permits, a somewhat more humble approach is even better.

Historically many of the most attractive human building sites have been at the transitions between natural elements of the landscape: at the edge of the forest, at the shore of the lake, at the crest of the hill or at the edge of the cliff. We seem to naturally want to build there.

However, it is sometimes more powerful to NOT put the house exactly on top of the transition spot but to set it back a bit and to view and preserve the transition spot as an outdoor natural space.

An example... There is a curving steep bluff near me that looks out over the water. There are two houses that have been build next to each other on the top of the bluff. One is an unassuming older cabin built on the flat of the crest but set back perhaps 40' or 50' from the edge of the bluff. The trees have been cleared at the middle of the view and the yard opens to the grassy open bluff top where a group of chairs and a fire pit sit. That dramatic full 180ΒΊ view is held back a bit from the everyday exposure of the house. The view teases you outside and always rewards your effort with a fresh appreciation of the beauty.

The second house is just being finished. It was placed directly on top hanging out over the bluff - a traditional two story open ceiling pointed prow of a house with a wall of glass exposing the whole house to the view. It is dramatic, and a visitor will certainly say WOW when they first come in. The owners, however are soon bored of the view and house itself appears merely ostentatious and self-important, a bit like an overweight despot commanding from on high.

It is true that a rare talent like FL Wright would have integrated the house into the site much better and perhaps been able to get the best of both worlds. Too bad most of us will never be or be able to hire such people. Yet all of us are capable of the humbler approach.

Longer term, we may even prefer it.
None of us are as smart as all of us.


Quote from: abraun on December 13, 2007, 03:49:30 AM
1)   Some additional research to determine the danger of soil slipping down should be done

Something the folks who built some of those homes we keep seeing sliding down the hillsides in California should have thought about.
Just because something has been done and has not failed, doesn't mean it is good design.


Hi everyone,

Thanks for welcoming me to the forum. I have been enjoying writing lately and, if you don't mind, I will keep posting my articles here - I can see that you are just the right audience.
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glenn kangiser

Hi Anthony.  We hope that you will also pop in here for some discussion too.  It's great having input from all around the world. :)
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin

Please put your area in your sig line so we can assist with location specific answers.


Any thoughts on a house being built on land where there is a rock quarry??


glenn kangiser

I think there are lots of interesting possibilities.  The foundation should be plenty solid  - maybe interesting views, alternative building materials?

w* to the forum, Cindy.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin

Please put your area in your sig line so we can assist with location specific answers.


unless we recognize who's really in charge, things aren't going to get better.