house building question

[bow-tie]

Hi all,

It's been quite a while since I've been on the site, but I thought of the combined brain trust here when I started noodling the building of a new house.

So here is my story. We're pursuing some property that would require a new crib. I want any house we build to be as efficient as possible. The land lays such that a berm home would be possible, which I think would be perfect from an efficiency standpoint (facing it south to capture as much passive solar heat as possible and the like). I figured living in a ranch home stuck into the side of a hill would help with cooling and heating (to some degree), similar to the premise of geothermal.

That being said, my research on the net has been baffled. I ran across a site proclaiming the awesome-ness of ICF (insulated concrete forms).... then I run across another site saying ICFs are junk (www.thenaturalhome.com) and so on. This is just one example of competing philosophies I have run across. I want to do this right the first time so I'm trying to get educated on the subject. There are so many options from the layout, to the materials, etc. Anyone have any resources they can point me to? Websites? Great books?

Any help would be awesome....

Thanks

 

[calmloki]

Last year we were all hot and bothered about a great home overlooking Prescott AZ that was sprayed shotcrete forms half buried in the hillside. Great place, but it had signs of water intrusion issues. Was apparent to me that you do NOT want to be getting into roof repair issues when said roof is under 20+ feet of dirt. AIR, they had used bentonite as the waterproofing medium. Issues you can worry about include radon and air quality, also running in any new utility lines (cable, water, telephone, etc.). Berm homes are at their best in extreme climates - in moderate temps there isn't much advantage.

 

[Sandhog]

If you don't have to deal with your local building code, you might want to build using mud bricks. Entire Santa Fe was build with mud bricks, adobe, before use of concrete stucco to make it look like adobe construction. Here is one of the web site may interest you. * Mud Brick - Earth Architecture

I built my hunting cabin extension with mud brick from my rich neighbor who excavated his large yard for pond. I also use recycle plastic bottles and grazing much like glass blocks and lighting with clear plastic bottles filled with little powder detergent with water under the direct sunlight to have lights throughout night for reading. I do have electric service but I rarely use it unless there is continual rain.Plastic-Bottle Bulbs Shed Some Light on the Situation - Design - GOOD

All depends what type of house that you want to build determines kind of construction. I personally like building with mud since it's readily available at no cost and mud brick with added reinforcement from items people throw out has near structural value of clay bricks or CMU. Most of all, it's cooler in summer and warmer in winter

 

[bow-tie]

I don't know if Iowa's climate would qualify as extreme. It gets plenty cold in the winter and plenty hot and humid in the summer if you ask me.

My minds eye of our house wouldn't include anything 'earthy' on the roof. Picture a walkout basement (dirt on three sides) with a steel roof instead of shingles...

 

[Sandhog]

I don't know if Iowa's climate would qualify as extreme. It gets plenty cold in the winter and plenty hot and humid in the summer if you ask me.

My minds eye of our house wouldn't include anything 'earthy' on the roof. Picture a walkout basement (dirt on three sides) with a steel roof instead of shingles...

Depending on the soil condition, you'll have to construct walls embedded in the soil much like retaining walls. And it can get very expensive since your have to cast in place reinforce concrete. Just do it with mud bricks and hire many unemployed construction workers in your area to construct. It's win-win situation.

 

[haha]

I don't know if Iowa's climate would qualify as extreme. It gets plenty cold in the winter and plenty hot and humid in the summer if you ask me.

My minds eye of our house wouldn't include anything 'earthy' on the roof. Picture a walkout basement (dirt on three sides) with a steel roof instead of shingles...

A friend of mine built a berm home north of Seattle. He was very gungo-ho about all the advatages. I sppose these may be great if everything works perfectly, but as Calmloki said, look out for the water. It became moldy and dank. I would prefer to live in a treehouse.

Ha

 

[73ss454]

I'll be spending enough time underground soon enough. I plan on staying on this side as long as possible.

 

[chinaco]

Two issues that I know about.

Before I get to that... about 35 years ago I got obsesses with energy efficiency and alternative techniques (during the oil embargo and carter gas spike years). I did a lot of study on techniques at the time. Two things I found.

1. Specifically with that type of home... humidity can be a problem. Like living in a basement. You can try to overcome it. But it is like trying to hold back the powerful force of water.... water usually wins. Of course, if you are in New Mexico, that may not be as big of a problem as a mid western state.
2. Resale. You will find a very limited market if you ever need to sell the home.

IMO - Explore techniques that will not affect the desirability and therefore resale of the home.... because your situation "will" change and it may mean that you need to sell it. Analyze at the total cost and total value if you have to sell it!!!

 

[travelover]

........
IMO - Explore techniques that will not affect the desirability and therefore resale of the home.... because your situation "will" change and it may mean that you need to sell it. Analyze at the total cost and total value if you have to sell it!!!

+1 You can make a new conventional home very energy efficient using careful orientation and building techniques. I'd also look into a geothermal heating and cooling system. Remember, too, that if you pass before your wife and leave her with a really unique home, she may have trouble getting anyone to do maintenance / repairs.

 

[bow-tie]

+1 You can make a new conventional home very energy efficient using careful orientation and building techniques. I'd also look into a geothermal heating and cooling system. Remember, too, that if you pass before your wife and leave her with a really unique home, she may have trouble getting anyone to do maintenance / repairs.

I thought if it was designed correctly, we might be able to get away with no geothermal, and not have any unique maintenance or repair expenses.

My idea is to essentially build a basement and put a roof on it. People have been digging basements for generations, so we hopefully wouldn't run into any unique water issues (of course, you are never guaranteed).

Humidity does seem like a big consideration.

I dunno, it's all still very preliminary.

I appreciate everyone's input... and keep it coming if you have anything to add.

Thanks again

 

[devans0]

I have been making our house handicapped accessible with such things as wide entries, easy open handles, ramps, etc. When I was wheelchair bound, it made life easier AND using a ramp to move a piano made a heavy job into an easy 1 man job.

Basements offer all the disadvantages of potential water or foundation problem and none of the advantages of a similar, earth berm house IMO.

In my area, (Iowa), there is a community of straw-bale houses with average utilities of two hundred dollars a year. I am jealous! I am looking at downsizing into a house that is built for retirement living and looking at options too, but will probably relocate. A house built for the extremes of -40 degrees F to 110 degrees F makes no sense in other parts of the country, so ideas will have to wait until I settle on a place and buy/lease the land

 

[skipro3]

I used a software program that let me design my own home. I could even do a virtual tour of the house, walking around in it and seeing it from the final perspective. I could also invoke a helicopter mode and fly around and over it to view it in 3D. When the house was finished, I put the program away. 3 years later, while cleaning up the computer I started the program and opened the file for my house. WoW!! It is amazing how realistic and accurate it was to what we ended up with . The great thing is that you can just move a wall, resize a window, change a roof line, etc. all with the click of the mouse and a drag-n-drop of any icon feature. Even picked out style of cabinets in kitchen, floor colors, paint, etc. I showed it to my contractor, drafter and engineer. It will even push out a materials list you can drop off at a building supply store for a bid. Door and window schedules, roofing materials, etc. it did it all. Check out any Fry's Electronics. There are several programs, some include add-ons for landscaping and terrain slope. Even able to 'grow out' the landscape. Plant a 5 gallon tree, then have it age out to 5, 10, 20 years and see if you maybe planted it too close to the house, or have shading problems later. Some have solar shading for your lat and long so you can figure out overhangs on roof, angles to capture sunlight in winter, maybe even a sunset or sunrise through a dining room or living room window.

 

[bow-tie]

...
Basements offer all the disadvantages of potential water or foundation problem and none of the advantages of a similar, earth berm house IMO.

In my area, (Iowa), there is a community of straw-bale houses with average utilities of two hundred dollars a year. I am jealous!...

devans0,

I'm a fellow Iowan, too.

I don't understand how a house built into a hill wouldn't have any advantages of a berm home. I don't have much for experience, but it doesn't seem intuitive to me. Wouldn't the earth provide some type of insulation? What about interior and exterior insulation? I've read about insulated concrete forms (ICFs) and structural insulated panels (SIPs). I've read about the strawbale houses, too. Not sure what to think of them with pestilence and whatnot (have to keep it sealed up tight, no doubt).

So much to learn...


skipro3,

That software sounds awesome. Do you remember what it's called?

 

[samclem]

I, too, have been intrigued by earth-sheltered, earth-coupled, and earth-moderated construction, but I think in many cases the advantages are oversold compared to modern, high-efficiency construction. You pay a lot to get the benefits of an earth-coupled home--all that digging/covering, all the increased structural strength needed because of the earth pressures, etc. And the water intrusion issue is real and significant. Plus, if you're like most folks you appreciate windows in your rooms (if not, you could leave them out of your conventional home and save the heat loss--but most people don't, and that's a big indicator of their desirability). And, what does this earth sheltering really achieve? It's not magic, it only reduces the daily and seasonal temp swings. Sure, it may be 30 degF warmer in the winter and 30 degF cooler in the summer 8 feet down, but your whole house won't be 8 feet down. A large portion of it won't be underground at all. And the number of folks willing to consider your unusual house when it's time to sell will be about 1-5% of the buyers for a conventional-looking house.

Regarding soils as an insulator: Dry soil has an R-value of about .25 per inch. Rigid foam insulations have an R-value of about R5 per inch. So, one inch of foam insulates as well as 20 inches of soil overburden. Plus, it weighs a heck of a lot less, and won't fill with water to collapse your wall/roof. Sure, thermal mass can help things a little, but this tends to be overrated. In the winter it is cold day and night, thermal mass isn't going to make a big difference in changing the total heat loss from the structure.

ICF is great. It results in a very well insulated house that is strong, tight, quiet, has thermal mass to moderate temps somewhat during moderate weather, and will be around for a century or so. Modern efficient conventional construction is cheaper and also very good: with careful attention to details and insulation (foam or densepack cellulose wall insulation, R5 foam sheathing, 6" walls or offset studs, etc) you can easily have utility costs equal or less than an earth sheltered home. And you'll have more light, a larger variety of available contractors, few worries about water intrusion, easy control of air quality, and the ability to easily expand the house, add a door, or sell the house someday. In many climates and utility-rate environments, a well-built tight house makes a ground-source heat pump uneconomical (the home's low heating/cooling costs make the higher GSHP installation costs uneconomical). But, if rates are high or the climate extreme, it's likely cheaper and more practical to take advantage of moderated temps below the surface by burying loops for a GSHP than to bury the house. You'll have far more surface area exposed to those moderated soil temps, you'll be pumping a working fluid through the soil so the heat exchange will be more rapid, and it will be practical to go deeper.

 

[Sarah in SC]

I've read about the SIPs and think they are a good idea, which we will probably incorporate into our next building project. I was more leery about the concrete ones.

Would you have an opportunity to talk to folks who've been living in homes built with alternative types of structures, maybe a few years after the construction? That would make me feel better if I had that kind of info.

 

[calmloki]

This is the place we were looking at - two story with a light "conning tower" sort of affair. Windows on two sides that overlooked Prescott. Curved walls made the interior pretty different and reduced the pool of buyers even more.

http://www.early-retirement.org/forums/f27/tankless-hot-water-heating-weird-home-50139.html

 

[Zathras]

You can build the house out of virtually anything and not have any issues as long as the construction is done well.
Basements are almost always built into homes in MN, not sure about Iowa. I know they are more rare as you get further south. As for insulating value of soil, it is a huge advantage. But only if done right so you don't have the issues many others have spoken of.

The students at NDSU built a 'passive house' recently and showed it off at the MN state fair. NDSU students show off super-efficient 'passive house' at State Fair | Minnesota Public Radio News.
They actually didn't use SIPS or ICFs. They built it with a double stud wall. Again, it must be built carefully, but any house should.
Another option is I-joists. I don't know a lot about the specifics. But my understanding is they are basically the floor joists (or very similar) built as walls, filled with insulation.

As for passive solar, south facing windows, as you alread mentioned, with enough thermal mass to absorb the heat from the sun during the day. It will then release that heat at night. Just so you have the right amount of thermal mass, it is very comfortable and lowers both cooling costs and heating costs.
Make sure to have some sort of shading that will shade the windows in the summer (when you don't want the heat) and let the full force of the sun in during the winter. I have seen a number of options, from awnings, to external shutters, etc.

The steel roof is a huge winner in terms of efficiency/durability. However, costs have gone up a lot in the last year (at least from what we have heard).

Good luck, and have fun! Lots of interesting stuff out there.

 

[ER Fireball]

If you are enamored with any alternative construction techniques or unique designs it might be very worthwhile to seek out some of the existing houses built with these techniques. 30 years ago we thought the bermed house might be interesting. There were several in the area, and they were showcase houses for a couple of the builders. A few years later you could buy them for 30 cents on the dollar because they had no resale value. A friend of ours actually rented and lived in one. It was OK, but nothing they wanted to own. Renting was the only way the owner could get some money back from the investment.

We also saw a geodesic dome that sat on a nice big lot. Actually, they built out by themselves in a development, and the lot on either side never sold. Even after the development sold out! Eventually somebody bought it and roofed over much of the dome such that it did not stand out so much.

Been in several A-frames, where there is a lot of space that has no headroom, accompanied by many spaces with huge amounts of headroom only a few feet away! And with roofing problems.

A friend of ours bought a house with a flat roof. Just like most commercial buildings with flat roofs, they spent a lot of money when they finally put in a membrane roof that wouldn't leak! Flat roofs make sense for commercial buildings, there really isn't a good alternative. But pitched roofs make sense when you are in an area that gets snow and/or a fair amount of rain. Or spend the money to get a commercial membrane roof.

There are many unique houses out there, and many alternative methods of construction. We incorporated a few in the construction of our house, and are now paying extra to remodel some of those features out! I have spent the money several times, and don't care about the tee shirt. In the future, I will own a relatively conventional house.

 

[skipro3]

Soil may have a low insulating value but it's also one huge heat sink. For example, here in California we have day after day of temps in the high 90's though 100's. But I couldn't help but notice that if walked barefoot across the lawn after the sun just set, the grass was very cool. I stuck a temperature probe into the dirt under the grass about an inch to 2 inches. It registered 73 degrees and the air temperature was still in the 90's and had been for many hours prior. While dirt may only insulate at .25R per inch, there's a much larger and denser 'push' the other way with the coolness of the earth and it's mass compared to that of air countering.
I've heard of geo cooling systems where pipes are laid in the earth and air is run through them to chill the house. Other than the costs to dig the trench and some 2 foot diameter culvert material, all it costs to cool a home this way is running a simple fan.

 

[samclem]

I stuck a temperature probe into the dirt under the grass about an inch to 2 inches. It registered 73 degrees and the air temperature was still in the 90's and had been for many hours prior.

In most of California the nights get cool even after very hot days. That, plus the huge amounts of water that the grass evaporates, accounts for the cool temps just below the surface of the grass.

I've heard of geo cooling systems where pipes are laid in the earth and air is run through them to chill the house. Other than the costs to dig the trench and some 2 foot diameter culvert material, all it costs to cool a home this way is running a simple fan.

You'll end up with a disgusting mold colony in the pipe and mold spores in your house in much of the US if you try this "earthtube" approach. Also, even where it is practical (i.e. very dry) it takes a lot of surface area in contact with the soil to transfer a significant amount of heat.

 

[skipro3]

In most of California the nights get cool even after very hot days. That, plus the huge amounts of water that the grass evaporates, accounts for the cool temps just below the surface of the grass.

You'll end up with a disgusting mold colony in the pipe and mold spores in your house in much of the US if you try this "earthtube" approach. Also, even where it is practical (i.e. very dry) it takes a lot of surface area in contact with the soil to transfer a significant amount of heat.

Well there's just no use arguing with sound science like that!

 

[chas57006]

I lived in a basement for 10 years, cool in the summer and warm in the winter.
However always damp and dark.

I now have a house with an east and southern exposure.
We also have geothermal. (can't say enough good about this)

It is so much better to wake up to the sun and have it heat your house.

Charlie

 

[Zathras]

You'll end up with a disgusting mold colony in the pipe and mold spores in your house in much of the US if you try this "earthtube" approach. Also, even where it is practical (i.e. very dry) it takes a lot of surface area in contact with the soil to transfer a significant amount of heat.

That is like saying 'your house will burn down if you use wood'.
Again, as long as it is built correctly, earth tubes work wonderfully. The have been in use in Europe for ages.
If you don't do it right, yes you would get mold. If you do it right, you won't.
The purpose of an earth tube is not to transfer all the heat you need. It is to temper the temperature of the fresh air intake to the house. Depending on you local climate a run of about 50' is pretty standard.
As I understand it, in Europe, it is fairly standard in new houses to simply wrap the tubing around the outside of the foundation of the house.

 

[ERD50]

Again, as long as it is built correctly, earth tubes work wonderfully. The have been in use in Europe for ages. ...

The purpose of an earth tube is not to transfer all the heat you need. It is to temper the temperature of the fresh air intake to the house. Depending on you local climate a run of about 50' is pretty standard.

As I understand it, in Europe, it is fairly standard in new houses to simply wrap the tubing around the outside of the foundation of the house.

Zathras, do you have any good links to these installations? The stuff I googled so far was pretty sketchy.

-ERD50

 

[Zathras]

Zathras, do you have any good links to these installations? The stuff I googled so far was pretty sketchy.

-ERD50

Here is a manufacturer's site with some details: REHAU AG + Co - AWADUKT Thermo - Air-ground heat exchanger system
Note, this one is kind of the 'palace' version. I have also seen houses that have this made with PVC piping.
You might also like this site: Passive Cooling Techniques
There are some statements I disagree with the author in his general notes section. But overall it seems a pretty good review of pros and cons with links to a number of sources. It is a few years old though.

As I understand it, the biggest area to be careful is the slope of the tubing and the drainage. Just like your roof, gutters, windows, etc, if water is allowed to pool in areas it shouldn't it can lead to problems.