Terra-Dome Earth Shelter Build

[patrick_g]

I seriously considered making the panels track, but have decided it would be quicker and easier to keep them fixed and just put in a few more panels.

Really good bang for the buck is single axis manually tracking mount where you preset the azimuth and adjust the elevation (latitude adjust). You make your mount adjustable in elevation and adjust it manually a few times a year to optimize your performance. Significant gain in performance at very low cost. Best bang for the buck and if you get too old, fat, lazy, or otherwise incapable of adjusting it a few times a year you just aim at the happy medium (typically 15 degrees below your optimum latitude alignment to get better winter performance) and tighten the bolts for the last time.

Pat

 

[Danno1]

I'm estimating my solar panels at about 70 pounds including water, so using two of the above mount points for each panel in a toe plate seems reasonable.



Steve
Maine

Better add in snow load too!!!



.

 

[mjncad]

Better add in snow load too!!!



.

And wind load.

 

[carpolisher]

I can see woodpeckers doing that, but no sign of them (plenty of them in the woods 30' off the back wall though). We'll keep our fingers crossed.

Steve

Steve,

I am planning to stucco the exterior soon. I was wondering how your job was done? Did you use extra long fasteners for the foam or just adhesive? Flashing details at windows and bottom edge? Cost per sq ft etc. I am also torn between the synthetic and traditional systems. Any info is appreciated.

Thanks,

Bob in PA

 

[sajurcaju]

Steve,

I am planning to stucco the exterior soon. I was wondering how your job was done? Did you use extra long fasteners for the foam or just adhesive? Flashing details at windows and bottom edge? Cost per sq ft etc. I am also torn between the synthetic and traditional systems. Any info is appreciated.

Thanks,

Bob in PA

Hi Bob,

The stucco was done by pro's, we did not consider attempting it. Look at the shot down the side of the building--that's about 50' that is pretty close to dead flat. They went in and rasped the mounted foam so the outside was flat, unlike the concrete which wavers back and forth.

They used a synthetic stucco made by Sto. The foam is glued to the concrete (no fasteners), then covered with a plastic mesh, etc. I think there are about five layers to it. It certainly isn't cheap; looking back at the receipts, it ran $8-10 per square foot including insulation.

Originally we were going to stoneface the entry, but the stucco looked so nice we decided to stay with it.

You have to flash places like the tops of the parapet walls where water can pool. The issue is keeping water out from behind the foam when it can freeze. Freezing water can break the glue lines. Incidentally, the glue lines actually space the foam off the concrete so there is a little room to breathe and let moisture out. There are some small "weep holes" along the lower edges in case of moisture.

I thought they had a brilliant idea for the windows (see pic). The bottom edge of the foam is cut at 45 degrees, so water and dirt won't pool there. It looks good too. We had one window in the front that the designer drawing the plans drew too narrow, which is a big deal with walls this thick. To help, the foam on the sides of that window was also cut at 45 to give a little wider view. Mirror panels along the inside of the window frame helped too. All of our windows on the interior are finished with varnished pine, I think it looks really nice.

The bottom edge isn't much. The stucco stops at one point and the polystyrene foam sheathing from the foundation shows. We put rock in some areas and dirt in others (raised bed gardens). Where we put dirt up against the house, we added a layer of epdm rubber roofing material just in case.

Steve

 

[carpolisher]

Steve,

Your stucco looks nice... What color is that? I glued 2" foam last fall just to get by and plan to put another inch or two. I know what you mean by the walls being wavy. Hard to get the foam panels to sit flush! I am considering extra long tap-cons and washers as a back up. I also foamed the shallow footers for frost protection. We are thinking of putting stone veneer on the 1/2 mod entryway. I am applying American Clay plaster on the interior walls and getting good with the trowel and hock. I have to think about the DIY stucco. Have you started the solar panels?

Thanks,

Bob

 

[sajurcaju]

Steve,

Your stucco looks nice... What color is that? I glued 2" foam last fall just to get by and plan to put another inch or two. I know what you mean by the walls being wavy. Hard to get the foam panels to sit flush! I am considering extra long tap-cons and washers as a back up. I also foamed the shallow footers for frost protection. We are thinking of putting stone veneer on the 1/2 mod entryway. I am applying American Clay plaster on the interior walls and getting good with the trowel and hock. I have to think about the DIY stucco. Have you started the solar panels?

Thanks,

Bob

The color looks dreadful in the picture. It was shot in the shade and the exposure is off (fixed with software); I paid no attention to the color balance.
The actual color is a pinkish earth tone. It's interesting how many different colors it looks like depending on the light.

I'd say that fastener backup to support the foam is probably a good plan for diy. The guys who put up our foam and stucco did a lot of surface prep. They used some kind of bonding agent on the concrete to make the glue and foam stick. There might have been a layer of mesh in there too (before the foam). Buy a hammer drill yet? I've found lots of uses for mine in a concrete house.

The solar panels are stuck in a planning phase until we sell our previous house...this could take awhile, despite lots of showings. If it gets toward fall, we'll get the panels up one way or another. I don't want to go through another winter with the propane bills we had this winter. I don't think the panels will pay for themselves in one season, pretty sure they will in two.

Steve

 

[mjncad]

The actual color is a pinkish earth tone. It's interesting how many different colors it looks like depending on the light.

Steve

Sounds like the paint on our house. We call it "chameleon" and it was caused by the builder painting our place a $h!t brown by mistake, then spray painting it the right color we ordered.

 

[carpolisher]

The color looks dreadful in the picture. It was shot in the shade and the exposure is off (fixed with software); I paid no attention to the color balance.
The actual color is a pinkish earth tone. It's interesting how many different colors it looks like depending on the light.

I'd say that fastener backup to support the foam is probably a good plan for diy. The guys who put up our foam and stucco did a lot of surface prep. They used some kind of bonding agent on the concrete to make the glue and foam stick. There might have been a layer of mesh in there too (before the foam). Buy a hammer drill yet? I've found lots of uses for mine in a concrete house.

The solar panels are stuck in a planning phase until we sell our previous house...this could take awhile, despite lots of showings. If it gets toward fall, we'll get the panels up one way or another. I don't want to go through another winter with the propane bills we had this winter. I don't think the panels will pay for themselves in one season, pretty sure they will in two.

Steve

I feel your pain regarding energy cost. Our electric bills were criminal. Earth sheltered homes are supposed to save energy. I have come to the conclusion that radiant floor heat is not well suited for them.
Due to low heat loss, typically during the day with passive solar , the slab is allowed to cool down. When heat is called for, the slab has to warm up again before it warms the room. This takes a lot of energy. A slab stat helps but you still need to heat massive amounts of concrete. On the plus side its quite comfortable. I am considering some kind of back up.

 

[sajurcaju]

I feel your pain regarding energy cost. Our electric bills were criminal. Earth sheltered homes are supposed to save energy. I have come to the conclusion that radiant floor heat is not well suited for them.
Due to low heat loss, typically during the day with passive solar , the slab is allowed to cool down. When heat is called for, the slab has to warm up again before it warms the room. This takes a lot of energy. A slab stat helps but you still need to heat massive amounts of concrete. On the plus side its quite comfortable. I am considering some kind of back up.

I've revised my thoughts on payback for the solar panels--it will happen this winter. We spent $4k on propane last winter, I expect 9 panels to cost half that much.

In your case with passive solar, what you have is a large time lag due to the concrete. Heat out = heat in, this doesn't cost any extra energy, just slows things down. Maybe there is an efficiency effect on your boiler though.

If I were to do this again, I'd put more than 2" insulation under the concrete floors, and more around the edges.

On the other hand, comparing notes with others in our area, last winter people did use more propane than usual.

Steve