I built my own strawblae house and have worked on half a dozen others. I have designed 3 award winning homes, one of them was strawbale.
Mice aren’t a problem, the walls are sealed with clay (inside) and lime (outside) render, the mice can’t get in.
Same with fire, the straw is tight and sealed, they don’t burn. In huge bushfires in southern Australia a few years back, several families sheltered I a strawbale home as the fire passed.
Moisture not a problem if you have proper eaves and footings, which you will cos you design it properly, right?
Loads of massive benefits over brick or stick built.
I have no data on wolves sorry, but definitely dropbear proof
If it’s safe from mice, bugs, and fire, then it just seems like the housing equivalent of wearing a boot on your head. You can do it. It’s not hurting you or anyone around you. But it’s kinda just weird. Is there some sort of benefits to this over a normal house? Or is it just a boot on your head?
Pros: Cheap, good insulator, doesn’t require any experience to install, local, low environmental footprint.
Cons: Thick, does not handle moisture well at all so it must be completely sealed. A small leak will ruin all the hay in the exposed area and, with a bit of airflow, can spontaneously combust. More likely, though, is that it just degrades rapidly. Like a lot of things, good planning can keep you fine.
Well, because straight earth as in mudbrick (or concrete, normal bricks etc) is not insulation. That’s thermal mass. It stores energy. Insulation (like strawbales) slows heat movement. So you need insulation on the exterior and thermal mass on the interior for a properly thermally regulated building.
At 2 inches thick of limestone, you can sure bust it up with a sledgehammer or similar. A punch won’t do much more than hurt your hand. Still, if you take tools to the majority of homes they break quite fast.
Couldn’t say houw tall they can get but from memory I think I’ve seen 3 stories? Over that you’re talking more full on construction. I’ve seen a 4 story using super bales that was in an commercial carpentry shop
The moisture and organic material causes mold and bacteria to form and create heat. Because hay is a good insulator, heat will build up more and more. Once the hay gets to a certain temperature flammable gases are formed and can combust from the heat.
But the moisture content of the straw matters BEFORE it gets sealed. A stack of a thousand damp bales can heat and combust. And it’s the interior damp bales that heat and start the fire.
They can get wet waiting for transport to the jobsite, they can get wet during transportation, and they can get wet during building.
I’m not saying a strawbale house can’t be well built, but it’s not a “one size fits all” solution for every location.
And that is the trick isn’t it. A piece of wood gets rained on, it isn’t effected much if at all. When the sun comes out, it dries in less than an hour. But bales are much like sponges, they soak up water easily and dry out very, very, very slowly.
Just how much do you try the average construction crew to keep those bales dry on a job site?
No they probably aren’t suitable for mass use. But, for one-offs they can be viable choices if you get a high quality contractor and construction crew that knows what is needed to build the structure correctly.
So people who were highly motivated to do things right. And not your average contracting crew that needs to do the work as cheaply and fast as possible and get to the next job quickly.
Well your average construction crew doesn’t build straw bale houses. The three I worked on it was a thing of real concern. We keep the bails covered before they were stacked. We would let the pile breathe during the day and cover at night. We would only stack a wall when we knew it would get finished and have the top cover on before the end of the day. And the exterior was sealed very early where the interior sealing was one of the last things to happen.
The point is the, the “average” construction crews build the vast majority of structures around the world. And you are correct - they aren’t qualified.
Yeah, same as wood, who would build houses out of that? /s
Hay is great insulation and it’s sealed with protective material anyway in modern houses. Also, even if not: Some tribes make houses out of hay or straw and those houses are quite great in their particular circumstances. There are experiments to use hay bales for structural support as well and it holds up surprisingly well.
Also, fun fact: wooden houses are less dangerous in case of fire than houses made of steel and concrete because the steel rod reinforcements start becoming soft at low temperatures (~200°C) and crash. Wooden houses announce crashing when burning, concrete buildings don’t.
So flammable mater + low airflow is somehow more fire resistant than flame resistant mater + low airflow? Looks like the source is pure marketing unless their comparable insulation is perforated cardboard coated in fuel gel.
Roof/attic often uses rockwool or glasswool. Wall insulation is often something like XPS, PIR or PUR.
Although it sounds counterintuitive, I can see straw doused in flame retardant being better than supposedly flame retardant polystyrene foam made from hydrocarbons. I mean, just look at what happened with Grenfell Tower.
“doused in flame retardant” isn’t mentioned in the source as far as I saw, plus it would affect the eco-friendly, workability, cost effectiveness, and biodegradability benefits mentioned (though the last one is worthy of debate as a pro or con in the first place). Everything has its tradeoffs unfortunately. This could be the better side for some surely.
From what I have read they are using a loam layer on both sides of the wall, I doubt that this affects eco-friendliness and biodegradability. And they are F90 certificated. source
Since straw bales are tightly packed, they do not burn as easily as certain other materials. The tight packing reduces airflow, something that is critical to sustain a fire. While there is some fire risk during the construction phase (as is the case with many building materials), once the home is finished, it’s flame retardant nature decreases the risk, usually resulting in a home that better resists burning than a traditional stick built house.
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