Terra-Dome Earth Shelter Build

[ND Vet]

We're going with the Hait version of passive earth tubes. I have them going in as pairs to take advantage of the heat exchange effect. A big concern is that the 3 high tubes have such a risk of shearing off from settling as there is so much backfill under them. It doesn't show on the plans well but the middle module has the tube coming out of the skylight side right at the top of the domed roof. Terra Dome wants to take the other two up vertically at the center of the dome and have to turn horizontally and slope downward. If we run them out horizontally the opening is such an oblong, angled, irregular thing that it would be hard to put a grate on it and hard for them to cut it. They have to be cut off flush with the ceiling because the forms to support the concrete are there. It seems like it would be just as big a shear risk with the 90 degree turn we will have to take above the vertical pipe. The tubes coming out of the bedrooms go straight down from the floor, join together in a wye and then come out under the footings and around. I know that 6 of the 4" tubes is inadequate for house ventilation but the 6" or 8" would be so expensive and leave such big vent openings inside the house that I just couldn't see doing that. There are other exhaust areas that go straight out the roof, exhaust fans in each bathroom, garage, and kitchen hood, along with the dryer vent going out. If they are running I expect that all the tubes will be bringing air into the house which changes all the heat exchange and earth temperature dynamics again. All tubes will be under the umbrella with the parapet and retaining walls wrapped in insulation to keep them under it also. They are 150 to 200 feet long and come out to daylight on the south side of the house. My other concern is whether the thin walled sewer pipe is strong enough not to collapse under the weight of the earth, 17 feet deep at the back of the house, and under a concrete patio plus a foot of dirt at the front of the house. Has anyone got other ideas for the pipe?

CW

 

[SamWalton]

We're going with the Hait version of passive earth tubes. I have them going in as pairs to take advantage of the heat exchange effect. A big concern is that the 3 high tubes have such a risk of shearing off from settling as there is so much backfill under them. It doesn't show on the plans well but the middle module has the tube coming out of the skylight side right at the top of the domed roof. Terra Dome wants to take the other two up vertically at the center of the dome and have to turn horizontally and slope downward. If we run them out horizontally the opening is such an oblong, angled, irregular thing that it would be hard to put a grate on it and hard for them to cut it. They have to be cut off flush with the ceiling because the forms to support the concrete are there. It seems like it would be just as big a shear risk with the 90 degree turn we will have to take above the vertical pipe. The tubes coming out of the bedrooms go straight down from the floor, join together in a wye and then come out under the footings and around. I know that 6 of the 4" tubes is inadequate for house ventilation but the 6" or 8" would be so expensive and leave such big vent openings inside the house that I just couldn't see doing that. There are other exhaust areas that go straight out the roof, exhaust fans in each bathroom, garage, and kitchen hood, along with the dryer vent going out. If they are running I expect that all the tubes will be bringing air into the house which changes all the heat exchange and earth temperature dynamics again. All tubes will be under the umbrella with the parapet and retaining walls wrapped in insulation to keep them under it also. They are 150 to 200 feet long and come out to daylight on the south side of the house. My other concern is whether the thin walled sewer pipe is strong enough not to collapse under the weight of the earth, 17 feet deep at the back of the house, and under a concrete patio plus a foot of dirt at the front of the house. Has anyone got other ideas for the pipe?

CW

I would consider using the schedule 40 or 80 water supply lines they are much stronger. We used schedule 40 through out our build. I have run these pipes over with our tractor many times with no problems.

 

[ND Vet]

I've been preoccupied with getting the plans finished and contractors organized and didn't get to posting. It has been painstakingly slow getting the plans revised and back. We have definitely jumped on in! Half the footings are poured and we are to pour the first of the modules in another week. Ran into trouble already because a concrete truck was late and we had a downpour just as they arrived. Couldn't get the truck close enough to pour and it had to go back. Now we need more gravel and a different route because of all our rain. Usually dry as a bone here this time of year! Well we don't have your heat problem Sam. It is 49 at night and cools off nicely. Cameron is the TD guy on site right now. The forms are supposed to arrive Monday.
I know Steve said he didn't have enough roof penetrations and I wanted to run by you what they have proposed for us. There are 5 of the 12" sewer pipe penetrations for the 4 solar tubes and the 2 bath exhausts, dryer vent, plumbing vents, satellite, phone, antennae or anything else coming into the utility room. There are 6" pipes in module 2 for stove hood exhaust and module 3 for bath exhaust & plumbing vents. The chimney flue liner is 8' and there must be something for the exhaust fan in the garage but I don't remember him saying anything about that. The earth tube sleeves are also in modules 1 and 3. It comes off the side of the skylight in module 2.
What experience does anyone have with Quickie vents for sinks?
BTW we are putting Penetron in the concrete on the domes, parapet and retaining walls. It is $25/yd so does get expensive to put it in the whole thing but we don't plan on using all the Econoline. We should only have to seal the penetrations and cold joints.

CW

 

[mjncad]

Hi ND_Vet:

Any chance you can repost the floor plan pictures at a higher resolution as they are pretty coarse, especially when blown up 3-times, and rotate them counterclockwise 90-degrees. One can get the general idea of what you're doing; but a lot of details are just blurs.

Thanks,

 

[carpolisher]

We're going with the Hait version of passive earth tubes. I have them going in as pairs to take advantage of the heat exchange effect. A big concern is that the 3 high tubes have such a risk of shearing off from settling as there is so much backfill under them. It doesn't show on the plans well but the middle module has the tube coming out of the skylight side right at the top of the domed roof. Terra Dome wants to take the other two up vertically at the center of the dome and have to turn horizontally and slope downward. If we run them out horizontally the opening is such an oblong, angled, irregular thing that it would be hard to put a grate on it and hard for them to cut it. They have to be cut off flush with the ceiling because the forms to support the concrete are there. It seems like it would be just as big a shear risk with the 90 degree turn we will have to take above the vertical pipe. The tubes coming out of the bedrooms go straight down from the floor, join together in a wye and then come out under the footings and around. I know that 6 of the 4" tubes is inadequate for house ventilation but the 6" or 8" would be so expensive and leave such big vent openings inside the house that I just couldn't see doing that. There are other exhaust areas that go straight out the roof, exhaust fans in each bathroom, garage, and kitchen hood, along with the dryer vent going out. If they are running I expect that all the tubes will be bringing air into the house which changes all the heat exchange and earth temperature dynamics again. All tubes will be under the umbrella with the parapet and retaining walls wrapped in insulation to keep them under it also. They are 150 to 200 feet long and come out to daylight on the south side of the house. My other concern is whether the thin walled sewer pipe is strong enough not to collapse under the weight of the earth, 17 feet deep at the back of the house, and under a concrete patio plus a foot of dirt at the front of the house. Has anyone got other ideas for the pipe?

CW

We used gasketed SD35 drain pipe. It has a heavier wall. The pipe was supported from the walls with chain and Tap-cons The gasket helps absorb the shock and movement from back filling. The dirt below the pipe was tamped to minimize settling.

Bob

 

[patrick_g]

Has anyone got other ideas for the pipe?

CW

Not to worry, the crushing forces on the pipe at the depth you mention (17 ft) is randomized and not so likely to squash a pipe as you might think.

Related experiment...

Put a piece of Saran Wrap or freezer foil over the end of a piece of water pipe (metal) or tube a couple feet long or longer. You can use a rubber band to secure the foil or wrap. Put the pipe/tube in a vice and secure it well with the Saran Wrap or foil end down. Fill the inside of the pipe/tube with sand or table salt or similar. Try to drive a rod (at least 1/2 the ID of the pipe) that will fit into the tube down into the sand or salt. Use a hammer and don't be bashful. Smack the crap out of the rod. You will not be able to push the loose covering off the other end of the tube/pipe. If you try hard enough you may enlarge the diameter of the pipe/tube but you will not dislodge the loose covering. The applied force will be randomized and dissapated, mu8ch at right angtles to the applied force. Be careful as the tube may get pretty hot if you really "wail" on the rod.

Pat

 

[Egon]

Not to worry, the crushing forces on the pipe at the depth you mention (17 ft) is randomized and not so likely to squash a pipe as you might think./QUOTE]

If memory serves me correctly the force on the pipe will be the weight of material that is contained in the "Angle of Repose" of the backfill material that sits above the pipe.

 

[ND Vet]

Hi ND_Vet:

Any chance you can repost the floor plan pictures at a higher resolution as they are pretty coarse, especially when blown up 3-times, and rotate them counterclockwise 90-degrees. One can get the general idea of what you're doing; but a lot of details are just blurs.

Thanks,

OK, see if these are better.

 

[ND Vet]

We used gasketed SD35 drain pipe. It has a heavier wall. The pipe was supported from the walls with chain and Tap-cons The gasket helps absorb the shock and movement from back filling. The dirt below the pipe was tamped to minimize settling.

Bob

How does the gasketing work? I am only familiar with solid connections.

CW

 

[carpolisher]

How does the gasketing work? I am only familiar with solid connections.

CW

The pipe has a rubber seal on one end which slips into the bell shaped end of the connecting pipe. Solvent is not used. The SDR 35 is usually light green in color and should be available at most plumbing supply houses. See fig. 1 in this link. http://pwpipe.com/literature/f/mkt-f-750.pdf