Strawbale in the Interior (Ester: renters, home, neighborhood)

[Grannysroost]

Originally Posted by MissingAll4Seasons

The physical size of the bales (14"+) does provide some thermal mass in addition to high r-value. If you were to add mud "cob" on interior & exterior with a lime plaster skim coat you can add more thermal mass. The argument between insulation and thermal mass is an old one, but the equation is sort of simple -- the more insulation you have, the less thermal mass you need to retain the heat (and vice-versa).

I love the 3 Little Pig story -- but I can guarantee that you can break through a 2x8 framed wall a heck of a lot easier than through a 14" thick wall of solid compressed straw bales.

Missing...Please do and I want pics...instructions...we need to build on and think straw idea even with earthquakes is good idea.....or I will let you know.....even if small structure for sh..ts and giggles....

[snkalaska]

Originally Posted by Marty Van Diest

Not sure, but I am also one for doing things differently. When you break the mold and start from scratch you almost always learn a lot. That learning turns into maintenance.

Here is one possible problem. A round roof is going to have many radial planes instead of just two like a gable roof. In Alaska, the extreme temperature variations, (150 degrees between summer and winter in the Manley area), will cause the structural members to expand and contract. That can tend to crack whatever you use for roofing...and you will have many places for it do do so. It's not such a problem with just one plane like a shed roof, but the more seams that you have, the higher the chances of problems. Thats why the most effiecent roof is a shed roof.

Thats only a possibility. Its not possible to foresee all the problems. You will discover them from experience.

I'm totally intrigued by what you're planning but for me, I would be afraid it would turn into a nightmare and end up costing me big time. I hope you keep us posted on how things go. I'm always looking for ideas on how to build cheap with some style.

[MissingAll4Seasons]

I can see that having more planes and seams in a roof could result in some additional maintenance due to temperature fluctuations. Hubby is leaning toward a sod roof if we go with a round house, so I'm off to investigate that some more. Another option for curved walls, or part of the walls, is cobwood masonry with a cener fill of some sort of insulation material (wonder if spruce needles would work, we'll have plenty of those!).

I'll make sure to keep everyone posted. One man's mistake is another man's learning experience

[klickitt]

build a living roof with straw, if you are going to go that route. Remember that any living roof or dirt roof or sod roof system is going to be heavy and complicates things some. That is not to say that it can not be done but you will need to account for it. The extra weight up high does 2 things that you will need to account for: #1 You will have to account not only for snow load but also wet weight of the roof and will have to have some extra support. Rain on that roof will be heavier than snow and if it is soaked, freezed and then gets a heavy snow on it, it is going to be heavier than you can imagine and you will need to make sure you have it supported well. #2 The wieght up high poses proplems with earthquake stability. A heavy roof in a swaying quake is not as good as a lite roof.

These problems can be taken care of but you need to think about them first and you might even think about talking with an engineer first before building a heavy roof system like that.

[GregW]

I suggest heating with a co gen system based on a 10kw generator powered by a Lister type slow speed diesel. Collect the heat from the cooling jacket and exhaust as well as the electricity.

If I were considering this I would get a double wall army tent for the summers and rent a hut on Maui for the winter.

[snkalaska]

I just got my MotherEarth newsletter with an article on earthbag homes. Earthbag Building Index Might be something to throw into the mix if you haven't already considered it.

[MissingAll4Seasons]

Originally Posted by klickitt

build a living roof with straw, if you are going to go that route. Remember that any living roof or dirt roof or sod roof system is going to be heavy and complicates things some. That is not to say that it can not be done but you will need to account for it. The extra weight up high does 2 things that you will need to account for: #1 You will have to account not only for snow load but also wet weight of the roof and will have to have some extra support. Rain on that roof will be heavier than snow and if it is soaked, freezed and then gets a heavy snow on it, it is going to be heavier than you can imagine and you will need to make sure you have it supported well. #2 The wieght up high poses proplems with earthquake stability. A heavy roof in a swaying quake is not as good as a lite roof.

These problems can be taken care of but you need to think about them first and you might even think about talking with an engineer first before building a heavy roof system like that.

Yes, living roofs are very heavy. I've seen some examples of people who didn't do their math first and ended up with their roof garden in their living rooms! I fully intend to get a structural engineer to review my plans so we can calculate appropriate bearing and transverse loads. Since we're looking to use trees on site for the bearing shell structure, I think the round timbers (6-8" diameter) would offer significant load bearing advantages. But if my engineer recommends archtecturally engineered beams, I'm cool with that too

I'm talking with a guy in northern Scotland right now who has a 20' radius round house (timber frame) with a reciprocating frame beams and a green roof. They don't get quite as much snow as I'll get, but they got tons more rain. So far, he hasn't had any problems with the weight on his roof (he estimates 60 lbs/sq ft during the winter rains), but did recommend installing a drainage layer (waffle) under the sod that helps the precipitation flow out to a guttering system. He used wattle (woven twigs) for this on his house and it does a serviceable job, but he thinks the engineered product would work better. In any case, he uses his roof run off (pre-filtered by the sod) for potable water! I don't know if I'd go that far, but it would be interesting to test.

[MissingAll4Seasons]

Originally Posted by snkalaska

I just got my MotherEarth newsletter with an article on earthbag homes. Earthbag Building Index Might be something to throw into the mix if you haven't already considered it.

Earth bag woud work as long as you put some insulation on the inside (earth isn't very good insulation but is great thermal mass). The only issue I had with earth bag is having to buy and stuff all the bags LOL! I helped with an earthship in CO and pounding all those tires full of dirt sucked

[MissingAll4Seasons]

Originally Posted by GregW

I suggest heating with a co gen system based on a 10kw generator powered by a Lister type slow speed diesel. Collect the heat from the cooling jacket and exhaust as well as the electricity.

If I were considering this I would get a double wall army tent for the summers and rent a hut on Maui for the winter.

We were just looking at a Lister for winter supplemental power! My HVAC engineer (has designed systems for AK & Iceland) thinks that a "small" woodstove would be plenty enough to heat either our SIP house or the strawbale roundhouse since the r-value is so high in both. But if we can collect the heat from any generator we use, we can certainly find use for it... in the greenhouse maybe?!?

[snkalaska]

Originally Posted by MissingAll4Seasons

Earth bag woud work as long as you put some insulation on the inside (earth isn't very good insulation but is great thermal mass). The only issue I had with earth bag is having to buy and stuff all the bags LOL! I helped with an earthship in CO and pounding all those tires full of dirt sucked

Off the website:
Polypropylene bags have superior strength and durability, as long as they are kept away from too much sunlight. For permanent housing the bags should be covered with some kind of plaster for protection, but this plaster can also be earthen and not particularly costly.
[LEFT]The ease[/LEFT]
When filled with soil they provide thermal mass, but when filled with lighter weight materials, such as crushed volcanic stone, perlite, vermiculite, or rice hulls, they provide insulation. The bags can even act as natural non-wicking, somewhat insulated foundations when they are filled with gravel.

The only drawback is you'll attract extremely large bees.