J Rubins

Dave Pennington wrote:Seems like the mushroom fiber would be good food for microbes or other fungi.
Is there any long term testing data to see how well this insulation lasts under real world conditions?

Material cost per cubic foot would also be very interesting.

Hi Dave,
One thing I think is really encouraging about the mycelium panels is that the fibers are so fine they have a hydrophobic effect and shed water for some time.  If you’ve ever tried to rehydrate a dried mushroom, you’d know what I mean, you really have to submerge them. This coupled with gas permeability allowing water vapor to escape seems more promising than many other natural insulators, and a big plus is its fire rating.  

Right now I’m running with the thinking that all natural building materials are food, but the same way we increase their longevity, materials such as wood, is by protecting them from the rot/decomposition cycle by keep water away from them, and by allowing them to breath with gas permeable envelopes.   But it’s true the research is still in the works.

And this panel is 3.44 cubic feet.  Material cost of four pounds of oats for spawn and ~1/3 bale of straw, some fuel for sterilizing the grain for a total of ~4 bucks.  That’s under a $1.50 per cubic foot.

Next experiment is to incorporate some percentage of used cardboard, which will increase the labor but lower the material cost further.  

Beau Davidson wrote:

How long did your panel colonize?  Is this image at the point you terminated growth and began to dry?  

Panel colonized for ten days and this is when I started drying.  Was going to go a bit longer but was concerned a downpour got the substrate too wet, which it did.  Caught it in time.  

In the future I’m probably going to grow the panels on boards and put some drainage in the bottom.  This time I just laid it on the ground which is why I didn’t put drainage in the bottom to avoid ground contact.

Still got my fingers, well most of them…🙂

Well, it’s been awhile but I wanted to show my progress. The test panel 30x60x3.5 isn’t dried yet but it’s finished growing.  It’s just ten days after inoculating!  I used oyster mushroom grain spawn (oats) about four pounds, about 20-30 gallons of chopped straw, pasteurized (18 hrs) with low magnesium hydrated lime solution (approx 300 g/45 gallons).  Layered the straw and spawn.  Went very simple with the form, just sheeting rolled around 2x boards. Leveled a nice area in the shade. This might be a pretty good method for scaling things up.   Apparently, mushroom insulation panels enjoy the shade under magnolias in the summer…Bummer to use plastic sheeting but both bottom and top sheets are reusable for more panel growing.  Top sheet has three rows of one inch slits every six inches or so for some gas exchange.  
I’m really pleased with the lime pasteurizing.   It’s the first I’ve done it, though one has to take serious care with eye and skin protection.  It’s really alkaline, but I guess no worse than making soap.  Oh yeah, figured I’d include a pic of my human powered straw chopper.  A little risky, sure, but I figured it was an idea others might consider—even cob builders.   The insulated door project looks great!  Will be getting to that myself at some point.  

Beau Davidson wrote:I went ahead and pulled some of my panels out of the fruiting chamber and out of their bins to get them drying.  I needed to reclaim the bins to start a new batch.

Some conclusions:

Some had a little too much moisture content.

The wood chips seems to not be quite pasteurized enough - on 2 panels, a few tiny spots of green mold began to grow and take over once in the fruiting chamber.  

I'd like to acquire some smaller wood particles - dust or small chips.

Some of the lightest weight, most fully colonized panels were the combo of wood chips/straw, surprisingly.  

Been busy with work and am catching up…great progress!  Boo green mold.  Was that on oyster mycelium or reishi?
A couple of the panels look very well-colonized.  Surprising about the weight.  I’ll keep that in mind when figuring out my own substrate mix!  I finally found some low Mg lime suitable for pasteurization.  In terms of sustainability, I hope to save the solution to reuse, keep pasteurizing multiple batches of straw.  I’m on the fence about using waste cardboard strips in the substrate also.  Will probably test it out though.  Gearing up my cultures this weekend!

Michael Ot wrote:

Beau Davidson wrote:J. Rubins chimed in over on my mycelium insulation thread - he is growing mycelium insulation in a manner similar to what I am doing, but in a form that will make panels sized perfectly for his yurt.  

permies.com/t/177485/Homegrown-Mushroom-Mycelium-Insulation-Panels#1396005

Just a bit of PTJ synergy for good measure . . .

This yurt comes with a felt cover apparently but the more insulation the better. Mycelium panels could be attached to the interior of the lattice and the cob wall could be built up to them.

Perhaps they could be pizza sliced and placed over the roof poles to insulate the roof. They could also be fixed under or in between any snow reinforcement framing but it would be a shame to completely hide the beautiful roof poles.

Very cool project, Michael!  Thanks for the heads up on this, Beau.  I haven’t gotten very far on my mycelium insulation, but I am also planning on the pizza/pie wedge idea for the roof insulation.  I am molding the panels with a one inch half-lap to help reduce wind infiltration too which I also suggest if you go this route.  It may help to give some wiggle room and get a better seal since gers aren’t exactly precision structures when set up (which gives them a whole heap of charm).  But I’m not certain yet of the half lap’s durability.  Will know in a month or so once the panels are made and will post results on Beau’s mycelium insulation thread.

Sporeless oyster liquid cultures going for the pretty standard rate which seems surprising. Can’t vouch for the sellers as I haven’t used any of their cultures.

https://millywyco.com/product/sporeless-oyster-liquid-culture/

https://www.mycocultures.com/product/sporeless-oysters-liquid-culture-syringe-pleurotus-ostreatus/

Hi Beau,

Absolutely,  much of the motivation for my project in addition to sustainability and regenerative materials is to find and share better ways to insulate the dripping wet mildew machines yurts can become in temperate, humid climates when using current techniques and materials (other than wool felt which is prohibitive in cost). Thanks for alerting me to the Reddit discussion on this.

I hear you about sanitizing standards, heck, my flow hood is set up in a corner of my current bedroom!  I do have some of that sanitizing paranoia often seen in mycology circles, though.  Your regimen seems sensible.  I’m also going to try a combination of lime and heat pasteurization for the final substrate.  Sawdust/heat, straw/lime then mixed and inoculated.

Yes! Solar hotbox for drying/ heat treatment also on my agenda, and a rocket stove heater for plan B.

Here’s this about heat treatment for drying by rocket stove in addition to grassroots mycelium insulation production by an organization called Critical Concrete.  Lots of cost calculation as well in Euros as they’re based in Portugal. https://criticalconcrete.com/producing-mycelium-insulation/

I’ll look out for research on spore resilience, and let you know, and I’ll see if I can turn up anything about sporeless varieties, though I suspect such cultures’ cost may be prohibitive for DIY folk, but who knows until you look.

Hi Beau,

I’m working on this, too!  Very cool to see this and am looking forward to seeing results and sharing mine as well.  Specifically I’m working on insulation for structures, and even more specifically for my ger/yurt.  I’ve been cultivating edible and medicinal mushrooms for a while now, been foraging for years.

Project at the moment is using Pleurotus ostreatus (common oyster) but I might give Flammulina  velutipes (enoki/velvet foot) a try too.  I isolated a local strain here in Illinois and it is a very fast colonizer, faster than oyster and almost as quick as Morel.  I’m using a mix of hardwood sawdust and straw (maybe some wood chip) for the substrate and shooting for panels 2” thick.  Forms are urethane coated lumber on the base and sides, top side either polycarbonate or plastic sheet with holes spaced and covered with micro pore tape for gas exchange.

Just now starting the cultures, agar (MDA) to liquid culture and will be working on it this season.  

For now I’m not planning on letting the mycelium fruit.  My understanding is  many in the past who are making insulation this way avoid this as it will release spores(lots and lots of them in the case of oysters).  Also having done some building in the past, insulation will almost always accumulate condensation due to humidity and delta T.  Water + food, substrate+ spores= renewed mushroom growth, not something too desirable in walls for me at least.  My understanding is the insulation panels are also often heat-treated in order to ensure the mycelium is inactive, read dead.   I believe spores are more heat tolerant than mycelium, too.The one thing about having that air mycelium skin that’s heat treated is that it is pretty hydrophobic, too, a plus, eh?

But some thoughts: there are commercial varieties of oysters I think that are low spore producers and I think some may not produce any at all ( the spores of oysters in particular can lead to growers developing lung ailments/allergies which is why such unique strains are sought after).  Forgive me if I missed that detail in reading about your work so far, but it is a concern for air quality, and longevity of the insulation.

I do like the idea of first getting a crop and then getting an insulation board or infill block from that one stone thrown!  Maybe those cultures are worth looking into?