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Joined: Nov 13, 2010
Location: Missoula, MT
Thinking about wrapping my tiny chilly cabin in pine straw bales this summer, but there is no info I can find about using pine straw for strawbale houses or house wraps. Anyone know anything about using pine straw?
I have ~5 acres of tall stalky grass available for making traditional straw bales with this summer before it goes to seed (seeds in the walls = mouse/insect food = bad), but doing so would involve a lot of work in cutting it, waiting for it to dry and/or turning it as it dries, raking it up, and baling it.
There's a hillside thickly covered in ponderosa pine right next to my house, with plenty of long, dry, dead needles on the ground. All I would have to do is rake them up and bale them.
And so I've been thinking why it would or wouldn't work, and of questions yet to be answered:
REASONS FOR PINE STRAW:
1) people do indeed make bales out of pine straw (like this video demonstrating a hand baler: http://youtu.be/aACdMEP0P80 )
2) i wouldn't have to do the work of cutting straw, waiting for it to dry / turning it, haul them across the fields to my house, etc. i'd only have to rake up the pine needs, bale them, and haul them the short distance to my house.
3) the pine needles are already dry.
4) pine needles are allelopathic, reducing the chance of mold, fungus, and insect problems.
5) pine tree covered hill is directly adjacent to my house = minimal transport downhill.
6) as is, the hillside covered in dry pine needs could be considered a bit of a fire hazard.
REASONS AGAINST PINE STRAW:
1) super flammable.
1) insulative value of pine straw?
2) pine needles get very brittle over time - would the bales hold up, or would they crumble and subside over time?
1) I'm slowing turning the surrounding acres of stalky grass into gardens, and I would rather not remove biomass from those areas. I'd much rather chop and drop it and use it as mulch right where it is. I don't plan on doing any gardening on the pine covered hillside any time soon, so I would be more comfortable removing biomass from that area (there's enough grass and brushy plants up there that I'm not too worried about erosion).
2) The straw bale wrap wouldn't be load-bearing, merely insulative. Of course I would be extending the eaves of the roof to keep the water off it, and putting the bale wrap on a good dry foundation (hat + boots).
3) Surfacing: A) I have a ton of cove tongue-and-groove wood siding that looks pretty darn classy. B) I can acquire horrendously ugly vinyl siding for so stupidly cheap that it almost becomes appealing. C) I also have a large clay deposit directly behind my house for making cob / clay slip to plaster the outside with (this option seems the most fire resistant but the most work).
4) The structure is small (450 square feet footprint, not very tall), and I have friends, so the workload of any of the options is doable.
Joined: Feb 02, 2011
Location: Cowichan Valley, Vancouver Island, Canada
Hi. I'll start with the disclaimer that I haven't actually done a minute of real work with these materials. Yet. But I've been researching the heck out of them and here are my thoughts.
Strawbales are also pretty flammable, although apparently the density of the packing means fire spreads slowly through a bale. Not sure how densely you can pack pine straw.
However, part of the fire and rodent and mould resistance comes from the plasters that are used over the bales. So if you were to finish your bales in earthen plasters I think it would go a long way to mitigating your concerns.
I would not put siding on top because that could compromise the breathability of your walls, leading to trapped moisture on the inside surface of the siding which will lead to mould and rot.
Joined: Jul 06, 2009
Location: Cascades of Oregon
Keeping the oxygen from the bales is the key to fire retardance so I would definetly plaster or stucco. Haven't tried working with a pinestraw bale, regular straw with its long strands make them easy to cut and shape around timbers and openings. Even though pondo needles are relatively long it might have an impact on workability. The pinestraw bales I'm familisr with were baled for mulch so they havent been a tight bale.
I keep thinking of getting poked with pine needles....ouchies. Of course mice think the same.
I am wondering if you could reduce the flammability of the needles where they fall to keep them composting in place and feeding the trees.
Joined: Nov 13, 2010
Location: Missoula, MT
So I didn't wind up doing this. I found wheat straw bales for a good price, so I used those instead. The airspace between the ground and the floor I insulated with pine straw that I compressed by adding a layer, stomping it down, adding a layer, stomping it down, etc. Altogether, it's nice and warm now.
Joined: Nov 17, 2012
dude just wanted to mention that the materials one uses to insulate are not all that is holding the cold out. In fact air is a poor conductor of heat. If you have trapped, non moving, air, it is a wonderful insulator. No need to tramp down insulating materials and fill in those gaps...you want them . Dont fluff it either, has to have something keeping the air from moving. If it is warm though, you did it right