sgt_woulds

Says a man who has never done it ! 🙂 Try shovelling 2 1/2 tons of it into wheelbarrows and making what feels like the equivalent of a round trip to the sun backwards and forwards! Geocell binds together making it incredibly hard to get a shovel in, (had to use a shallow frying pan in the end) - moving it was the hardest physical thing I've ever done. I'm saying this as an ex-roofer used to shifting tons of slates up onto a scaffold 'cos the boss was a tight old so-and-so who wouldn't pay for a Bumpa. Other than that, yes it's lovely and light...

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You could try the Geocell system (from Mike Wye) - although it would mean wheelbarrowing a ton of expanded glass rubble to your back garden which might be just as hard as pumping concrete there. Is very DIY-doable though: Back to Earth also do something similar: Solid floor insulation – How to create a solid, insulated floor - Back to Earth

Yes, but Egypt tends to have less rain - although I suppose the Pyramids and other buildings probably get sandblasted regularly! Lime render may stand up to extreme weathering - but I'd take the advice of an expert - there don't appear to be any on here at the moment... These walls will likely be seeing horizontal wind-driven rain on a regular basis - if a stone rain screen can be made to work it will probably require less maintenance than a Lime render. Scottish John - I've not heard of this being done with bales, but the situation will be similar to using a brick or stone face with a ventilated cavity on a timber frame building. Will need to be signed off by a structural engineer. I'm sure I read an article in a (very) old magazine where the owner used a drystone wall over rendered bales for a shed/study. Can't remember if/how it was tied in, but it's not beyond the wit of man. I wouldn't want to try it though - would be Mouse City... On a separate front, a rubble foundation would not only be cheaper and easier to self-build but might also reduce the embodied carbon count enough to justify using a more conventional structure/insulation without so much environmental guilt. To annoy the FUD brigade - this is quite often employed with Earth Bag construction which the OP could consider as a more weatherproof construction method, with suitable internal insulation 🙂

The OP also said they planned to clad in stone; in any circumstance, they wouldn't leave the straw exposed to the weather. I wouldn't be confident about using lime render in that exposure zone without expert advice, but that come back to my point about designing for the conditions. As an example, our woodfibre insulation can be used behind a close-slatted rain screen or roofing without a weatherproof membrane in most circumstances - but in high exposure zones, we always specify a membrane for belt and braces. Similar consideration should be given when designing with any material. You wouldn't clad the building in EPS without protection for the same reason.

I'm not advocating either method, I don't write them off either. I think using them for infill is a better idea - the blown straw you linked to is a case in point. They are also designed to be stacked for storage and thus to take loads. The amount of loading and the timeframe in which it will maintain structural integrity is for a structural engineer to confirm, but can also be gleaned from empirical evidence of existing strawbale structures. There are many issues with straw bale construction as ProDave has rightly pointed out, but has anyone got evidence of a structural failure that wasn't due to poor design or construction? A house shouldn't be made out of them because they are polystyrene! Strawbales should be thought of like SIPs and the building designed accordingly. You could argue that SIPs are rubbish for a number of reasons, (I wish I'd built my extension from anything other than SIPs - a story for another day) but I don't think anyone here would argue that they are inherently structurally inferior to 'traditional' methods without some sort of evidence.

and should be used as animal bedding, not to build houses in a very wet and windy part of the world there is a reason why they built crofters cottages from stone when they did not have the mechanical means of moving heavy objects easily 2-300 years ago and it is why a lot of them are still standing us it to build an insulating inner wall by all means but not as an outer weather shield Who said anything about using it as an outer weather shield? This isn't the 3 little pigs 🙂 There is plenty of straw for bedding - using the excess for embodied carbon reduction in new homes is an ideal use for the rest. At the moment - as I understand it - most of the excess is burned to make power, which is nuts. Back in the day an exciting - but unpleasant - job was to help with burning the stubble fields to create biochar to be ploughed back into the ground. This is, (rightly) no longer allowed so all straw is now a low-value waste product of producing food crops. The farmers buy back the 'biochar' from power production at inflated values to perform the same function they used to achieve for free, (barring labour costs and the odd visit from the fire brigade). I agree that using stone for the outer face of the construction makes perfect sense in this location due to the weathering; if quarried or recovered locally it makes for an excellent low-embodied carbon building material. Crofters cottages were often insulated, (inside the stone!) with wool or heather - they made use of what was easily and cheaply available. [That’s why they built with stone. If they’d had bricks or abundant timber they would have used that instead] A friend of mine stayed in a cottage on the coast in Norway that was renovated using some of the original wool which was still in perfect condition after 80-odd years. No reason to assume that any other natural material,(suitably protected) wouldn’t last as well. I doubt if fibreglass or PIR would be suitable for reuse in the same circumstances. I do agree that we should be looking carefully at the chemicals sprayed on crops that become insulation – but this applies to crops in general. Industrial farming commits a lot of environmental crimes in terms of chemical use – but compare this to insulation produced by the chemical companies. Most VOC will dissipate naturally in storage before entering the building and the remainder will be effectively locked away from inhabitants behind the surface finishes. I’d rather have this slight risk in my home compared to the toxic soup of chemicals used by unnatural insulations. We have hijacked this thread and I don’t want to get into the weeds about the health benefits of natural, breathable, [not the best term but it’s the one people understand] construction materials. This discussion is about the suitability of straw for the OP’s use and I haven’t seen any logical arguments presented to preclude its use in a properly considered and constructed building in his location.

"Bales are naturally compressible and the building will move throughout it's life and you'll have jamming windows and doors and extra cracks opening up allowing air to leak through the structure with the associated impacts on comfort energy efficiency and building durability. " Would you tell someone not to use a green oak frame for the same reason?

To be clear, I'm not sure that structural straw bale is the best solution for the OP's location, but is perfectly viable for infill insulation. He'd be shipping in insulation anyway, might as well be natural / low(er) carbon stuff.

Thanks, that's exactly the kind of evidence I was seeking. I have seen that post before and, from my, (admittedly not top notch these days) memory this is the only such site where I've seen such complaints. The build referenced seems to use materials finishes that have not been considered in context with the build location. Earth/clay external render rather than lime, plasterboards internally rather than direct applied plasters. He moans, but does not answer any of the sensible questions asked by the others. As such it is not helpful because we learn nothing to ensure better buildings in the future. The great joy of the natural house-building community is the willingness to try new things and share what works and what doesn't. I think the methods he used were probably poor and more concerned with being cheap than being effective. I can only speak from the UK context, but cob buildings in areas with burrowing bees etc changed to using Lime render to prevent them digging in. Lime - (or at the very least a lime wash) is also very effective at deterring rodents from chewing through. They are unlikely to be burrowing into the bales themselves, but living in spaces formed between external finishes and gaps between bales. Like you, I grew up playing with straw and hay bales - stacked in the traditional manner in barns. We used to find rodent nests, (and feral kittens) in the straw stacks, but only in the gaps between the bales - they either couldn't chew into the dense straw or wouldn't waste the energy to do so. In the hay bales they would chew and dig in, but this was probably because they were much easier and full of seeds to eat. Rodents are opportunists - they make use of what exists and will find easier places to live if the opportunity arises. That's not to say they couldn't chew their way in, it's just unlikely - more likely they found a gap in the building and exploited it. Mesh could be a perfectly viable solution in some cases and why not? It is regularly used for external render works - why would this make the build less viable? You'd only need it for the first couple of feet unless you have Parakeets in the area; nothing is safe from those little green barstools - but again, design accordingly or buy an airgun. I agree with you regarding the vagaries of weather on straw production and modern methods of farming - but this has nothing to do with the underlying qualities of straw and is about care in the selection and use of materials. If straw becomes more valuable as a resource to farmers when sold for insulation then they will invest and change methods accordingly. There certainly should be a premium paid for any material used for building purposes. Cost has nothing to do with this topic though. This is about building a healthy low-carbon building that is better for people to live in. It is about the suitability of the material for its location and use case. Straw won't be the best option in all situations, but it is one of them. A lot of people are prepared to pay more for natural materials and offset this by supplying more of their own effort and time in completing. Sadly, most buildings with natural materials will cost more since they are not produced on the same scale, (or as heavily subsidised) as unnatural materials. U-value is a matter of providing enough depth but your figures seem wildly pessimistic. Ecococon 400mm panels using straw compressed at 115 kg/m3, (probably much higher than a standard strung bale) have U-values of 0.15 W/(m2K). Where are you sourcing these figures? Compression and movement should be assessed and ameliorated in the design and build, but historically a building that can accommodate movement to a certain extent tends to be longer lasting than a rigid one. Are there any reports of modern bale builds with non-opening windows and doors?

Gypsum is more common in France - they even have blocks of it available to build partition walls which I wish we had here. Contrary to popular belief, Gypsum is vapour open (most materials are to a greater or lesser extent), but not as vapour open as clay or lime. In this building, it was probably working as an internal VCL which could explain the excellent performance and longevity of the building.

Straw is just another option. With any building material, the important thing is how it is used and maintained. There are thousands of poorly performing buildings being built every day with a multitude of materials. I doubt that any of them will still be standing in 600 - 6000 years time. But the odd self-built house, (of whatever material) just might.

Without going too deep into history, straw bales were initially used in America by necessity. It was what was easily available and cheap for people settling in new areas. Plus there was an embargo on transporting straw and hay by railway so there was much more supply than demand. Once sawmills and brickworks were set up it became easier for more affluent people to build with 'modern' materials. This set a fashion and pretty soon straw was considered "a poor man's construction method'. People even demolished their old houses and rebuilt with sticks and bricks when they had more money to improve their personal image. This had nothing to do with the quality of the original building - which by most reports were warmer and quieter to live in than their replacements. The remaining straw bale buildings in the USA are a testament to the longevity of natural building materials in the right circumstances - the fact that there are so few remaining has been driven by human foibles, not inherent drawbacks of the build materials. As with cob, adobe, and wattle & Daube buildings, Straw bales built with adequate protection and sympathetic maintenance should last as long - or longer- than their contemporaries made from 'modern' materials. Some of the oldest buildings in the world are made from earth, not bricks; I've heard claims for some as old as 10,000 years. In the UK we have Cob and Wattle & Daube buildings dating from the 1600's. I don't think strawbale will ever be a mainstream building product, but it might make sense for a Self-build in the right location. And it certainly makes sense to use it as infill insulation alongside hemp and woodfibre. It does seem that the naysayers are basing their opinions on fear of the unknown rather than evidence.

Iceverge, Steamy Tea and others seem to have an aversion to strawbales. Please could you point to sources for evidence of failure? Correct levels of insulation and airtightness are a matter of design and attention to detail during construction; this applies to any material, natural or unnatural, and self-builders are likely to put more effort into this than 'real' builders. Personally, I'd rather see bales insulating a frame rather than performing two functions, but I'm not aware of any building of either style failing in use that wasn't due to poor detailing or construction. As with traditional cob buildings, wide roof overhangs, decent lime render, and gravel splash back zone, (with free-draining foundations) there is no reason a properly designed and built straw bale building shouldn't stand for hundreds of years in the majority of inland UK or Europe. E.g. World’s oldest known timber-frame straw house | EcoCocon | EcoCocon In the OP's location, the addition of a, (ventilated) facing of stone makes sense - although if it were me, I'd be looking at the traditional historic vernacular for highly exposed coastal locations, which tend to favour single-storey earth-sheltered or partially underground structures. Especially given the more energetic weather likely in the next 100 years.

In a normal situation with BSS kettles, ovens, immersions, etc would run off the solar and battery with grid backup if there is too much demand and the battery would be depleted well below 95%. It also wouldn't immediately recharge to 95% after use. Thus it would be in a more depleted state towards the evening with normal use case and charging profile. Perhaps I'm not understanding your setup correctly, but it sounds like you are not letting the battery drop below 95% during sun hours or overnight when it charges on E7? How many hours in a day will it deplete below 50% or complete a full cycle from 20-80%?