Bob Bobserson

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since Aug 30, 2018
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Recent posts by Bob Bobserson

Welp, continuing on this idea....I started to play around with some actual designs.

I figured a 3 foot rise to a 2 foot back on the terraces should be enough for the retaining walls (even though they are just extra insurance, since there won't be moisture in the ground around the structure). That means the terraces themselves eat up 6 foot along the walls on each side....which made hallways far too large to make sense. So for hallways I would instead do steeper terraces with additional pole supports? Also making them longer than normal to avoid those sharp curves and leaving enough earth for the walls.

3 foot also happens to be the right height for kitchen (and other) countertops in a house....which means you could finish them with tabletops.

For work desks or bed (which are a little lower), cutting into the terraces a little made sense. Losing a little height I doubt would destabilize everything on the last terrace (and actually, for the bed, it is extended out to sleep on)  

Also, when I was considering it, doing sharp angles in the house wouldn't leave enough earth for structural support for the roof. This meant they needed more forgiving curves.

Here is the general idea....

And this gives a better view of what is happening with the walls.

And here is a view that gives a better idea of the living area. Seems spacious enough for a decent place.

9 months ago

For the roof I wasn't even going to use a pond liner, just beams, crossbeams on top of those and sod on top of that. Should be waterproof if done tightly, and the smoke from the open hearth I'd heat and cook with should preserve the wood and keep it from rotting.

I don't think that will be waterproof....and the wood, in contact with damp soil, will DEFINITELY rot. Trying to smoke it won't save the house from slowly deteriorating. Sod houses (or turf houses) usually have extremely thick walls and constantly need to battle with moisture.

And if you aren't waterproofing the surrounding soil, you are going to deal with water coming in through the walls (or even flooding). This will lead to erosion issues, insect problems, moisture / mold, frost heave....and poor insulation (damp soil is the worse).

Basically, the entire idea of the above is to try and tackle the common problems with dugout houses. To stabilize the conditions in the soil so you can stabilize the conditions inside for a livable space.

The main hall I was going to have level with the slope of the hill, the uphill side rooms a little more underground and the downhill side rooms poking out of the ground just enough to have windows at the top. Of course the uphill rooms would have to have steel beams or something to keep them from rotting and collapsing, and the downhill ones would need vertical corner posts since they're partially above ground. Also steel drainage pipes so the roof didn't leak where it interrupted the slope of the hill.

A larger structure in the hill would require excavation of essentially the top of the hill. And then you would need to rebuild it burying the rooms. But if also need to be careful the surrounding soil can support the roof (and the weight of all the soil you pile on top to rebuild the hill). So for that you need built walls....or, as I theorize, terraced retaining walls to increase the weight load / stability of the walls.

Since a hobbit hole isn't supposed to be nasty or dirty or wet, I was gonna cob the walls and paint over them with lime for waterproofing and that nice whitewashed look.

Well....cob needs to breath. That is why it doesn't work so well up against soil (ESPECIALLY damp soil, which will all absorb into the cob walls and be miserable). Lime won't waterproof anything need to deal with the moisture in the soil or it will just seep into the house.

Don't look at hobbit houses for inspiration. That is fantasy from a fantasy writer. Look instead at traditional underground or earth bermed houses. These were the first kinds of houses and used for thousands of years by native people around the world. From the turf houses to the pit houses to all sorts of dug out shelters....right up to modern bunker design. There are a lot of designs that use the earth as part of the building, instead of just an obstacle the structure is fighting with (which conventional underground homes do now).
9 months ago

Bob, are you going to give this idea a go? I kinda want to see it!

Not for a bit, just thinking out loud at this point. Researching what others have done and where the pitfalls are.

I do think that you might be able to get by with less if you used a ditch witch or a small bucket on an excavator to dig a deep trench around the room, dropped a sheet of 2" foam board in vertically, and back filled the outside with gravel.

Yea, I was thinking along those lines. It isn't complete insulation (since there is still contact from under, but no real way to deal with that without digging out the walls....which turns the entire thing into an entirely different type of structure)....but hopefully enough to create a temperature grade to keep it comfortable inside? Dry earth does have some insulation properties (wet is horrible, but ideally the area around the structure should dry out).

Here is the current version of the idea.... terracing the walls means they can be supported by basic loose stone retaining walls (each one being 3 feet high, creating a natural seat / shelf surrounding the rooms (which can be turned into cabinets or closets, or just shelfing / seating)). And then a higher terrace that would give the entire room storage.

Roof wise "could" be done as vaulted....but this version is just super simple (the type used for quick bunkers). And shifts the load back a bit away from the opening. You would still get the sloped roof though, since the liner is placed on top of packed earth.

I saw a guy use a pond liner for a roof in Grand Designs S14E06 on Netflix, though it wasn't a pit house.

Thanks for the tip on the show! I was just checking it out and it looks like a great show.
9 months ago
I've been thinking about it more, and I guess there are a few ways you could evolve the design.

David Baillie is right, it looks like it is meant to go on a hitch (so the bulk of it is built onto a trailer, and then they added a front cabin with a smaller engine for smaller movement on its own. There are videos of it driving around a bit).

Then when parked, I guess you could do some type of stabilization (tie it down).

Perhaps a better idea would be to have the wheels on a hydraulic system that you could lower it fully onto the ground?

9 months ago
So, I found these stacked mobile houses....that look SOO adorable.

My question is, is this even possible to do? From road regulations and how vertical it is (not much stability) seems like it is more an art piece than an actual option for nomadic housing?

9 months ago

He loved his home, it was a comfortable one man home for 30 years and if cancer had not taken him he would be there still.

Yea, pit houses and other types of these houses have been used for soooo long. If we could solve the moisture / stability issue (pond liner + proper drainage to keep water away)....these would be such cheap alternatives to some of the more labor intensive types of natural houses.
9 months ago

In this case, I live on a big hill, and the house itself is situated so that on all four sides, water drains away from the foundation. And on one end there is enough slope, and a pipe to drain away what accumulates for water away. That is about it.

It sounds like you are dealing with some surface water with the slope (depending on how sloped it is)....but nothing for ground water? No wonder it is filling up. The problem isn't hydraulic force (?? the pressure of water underground isn't really much....cracking from water comes during frosts, that type of force does get substantial), it is just normal water moving to areas of lower pressure (and a big open void next to it is a pretty good candidate as it leaches through the ground).

To live down there, someone in a dugout house thay could backfill with rubble, use pond liner, and use 8 inch drainage tile so in a 25 year flood an enormous volume of water would be trapped and then flow away to daylight...but what is the cost of all that? Possible? YES! At a cost that is comparable to a WOFATI that is built on top of the ground and then covered with earth so that it is sheltered and given mass? Comparable at best, and most likely more expensive.

Not if you design to manage the water BEFORE it reaches the boundary of the foundation. The design I propose is managing the water far away from the building.....not only in the slope , but ALSO keeping water from penetrating deeper into the ground near the house (using a pond liner extending far around the area)...AND underground water drainage for any water coming in laterally before it enters the area....

If you don't stop water from all the ways it can get into the house, then of course you will have water issues. It isn't about doing "some water management", it is about doing a complete system of water management to keep the ground dry.

It is a pretty simple concept. Dig a big hole and when it is dry out it will be dry. And when it is wet out it will fill with water. Now we can change that easily enough by doing this, that, and the other thing, but then it all adds into cost, which being inexpensive housing was the SOLE purpose for doing it in the first place. Take that away, and it is no longer worth doing. Add in safety and comfort factors and it REALLY is not worth doing. So then it begs the question; can we build above ground using cheap methods, and the answer is YES! Building a WOFATI or other ways often talked about on here is probably is cheaper, and a lot more Green in nature as well.

The cost of what I'm talking about should be far less than something like a wofati (or any traditional house). You essentially just need digging equipment, crushed rock, and a pond liner....

Wofati are just buried log cabins. I'm not really a fan of their design. They don't seem to be dealing with the underground moisture issue to a far enough extent to avoid the high humidity and moist soil (which will eat away at their wood and make pests a problem).

Wofati are also pretty expensive since they use a TOOONNN of wood. Unless you live in a forest and are logging it all yourself (still expensive in terms of labor and equipment).

9 months ago

Travis Johnson wrote:I even have a house with a dug out basement, lined with field stone and it has some benefits even with a conventional home above it: it stays really warm in the winter. But as well draind as it is, during the spring its ability to drain water is superceded by the amount of rain and snowmelt and so it floods.

I'm curious how are you handling the drainage around the property before it comes near the house and the strategy to keep it from the basement?

Knowing where things went wrong could help to design to fix those problems.

My theory is a very generous water barrier + deep drainage around the perimeter should keep water from getting into the ground near the structure (so no soil to soil moisture transferring, and no top down moisture coming....and the capillary action of soil isn't enough to force itself up feet worth of space). And condensation issues would just make it uncomfortable (though, unlike other underground houses, since there is no moisture in the surrounding shouldn't have unusual humidity with proper air flow).

The problem is, like you point out, most of the examples are of dugout structures aren't solving for the water of course they are having water issues (even into catastrophic cave ins as the soil is destabilized with too heavy of rains).

I'd love to find some examples of the approach to trying to manage the water in the soil all around the area (instead of just at the house point).
9 months ago

John C Daley wrote: If it was a truely great concept, it would be in operation today.

I'm sure people could have said the same about earthship design a little while ago when it was first proposed as well...

What we do today isn't perfect, there is still room for rethinking and revisiting older techniques (under a modern lens).

The problem with earlier settlers accounts of dugout style houses is they didn't have the materials to really handle moisture. Pond liners weren't a thing back they were left with wet soil during rain and just doing the best they could.

But these types of earth structures are some of the earliest buildings mankind used for thousands of years (and they are found across every continent). Only today we have the easy access to materials like a pond liner that can make waterproofing the entire area a breeze (the same with modern digging technology to make the task of digging the hole a job for a single person in a day or two).

It is still dependent on the soil you have to work with.....but the big question just comes down to if you can manage the moisture well enough around the area and protect it all with something like a pond liner. I can't think of a reason why that shouldn't be possible? And, actually, thinking about it seems downright easy.

9 months ago
Engineered soil seems like it would be necessary for really difficult soils....but I don't know if all would need that. Like here in California, outside of my house is a 15 foot tall unsupported cut out of a hill (we live on a mountain, so houses going all the way up). Even unprotected this ground isn't going anywhere (and that is in an earthquake prone area even).

It sounds like the Irish were trying to solve the moisture issue just through aggressive drying and heating inside of the living space in an effort to make it more comfortable....but unless the moisture is kept far away from the walls (from the outside), structural stability is constantly shifting....and a bad rain would turn it to mush (which is why they had the cave ins I bet).

Now aday I think a full water management design could solve a lot of those problems (drains, landscaping, waterproof linings covering a larger area). Even the moisture inside of the living space wouldn't be enhanced by additional moisture from the walls (which seems to be the case with a lot of underground structures).
9 months ago