Fungus in cob, part 2

[phillc]

Hi all,

A while back I posted about having found some fungus strands in my cob walls. I didn't think then (and I don't think now) that it is dry rot as I don't see any obvious signs of it attacking timbers - maybe it is in hiding, but I've stripped back and examined all the obvious hiding places. I think it is something that is attacking damp cob - possibly the straw in it?

Anyway, hacking off for the grand re-render starts today and we found a big patch today, hiding in an area of cob we knew would be damp and will need rebuilding. This time, I got a photo!

Strands are no more than 0.5-1mm wide, white and floppy. I see no evidence of thicker or directed growth (like a dry rot style "ivy root" off on its travels), just this sort of loose matting. No real evidence of it being in neighbouring dry cob.

That cob's all got to come out anyway as it is dead but any idea what this is?

Thanks

Phill

 

[Cubist]

Well you've got me puzzling. Those strands, insofar that they've survived the process of the render being removed, is it reasonable to conclude that they are fairly tough and do not fall apart or disintegrate when handled? is it firmly anchored in the cob or does it break loose easily?

 

[Cubist]

Coo. Just found this.

Mycelium, the root structure of fungi, can be found in cob walls as it's used as a natural binder in the construction material. It's a key component in mycelium-based building materials, offering a sustainable and eco-friendly alternative to traditional construction methods. The mycelium acts as a glue, binding together the other components of the cob wall, like clay and straw, to create a strong and stable structure.

Here's a more detailed explanation:

• Mycelium as a binder:
  In cob construction, mycelium is not just a contaminant; it's intentionally cultivated and used to bind the other materials together. The fungal network grows within the cob mixture, creating a strong, natural adhesive.
  
  
• Sustainable material:
  Mycelium-based building materials are considered sustainable because they utilize natural, renewable resources and can be composted at the end of their life cycle.
  
  
• Advantages of using mycelium:
  Mycelium offers several advantages, including low cost, low emissions, and recyclability, making it an attractive option for environmentally conscious construction.
  
  

 

[phillc]

Thanks for the replies.

First, no, the cement render has well and truly delaminated from the cob in this area so there was a 1cm gap for it to grow into - pulling the render off hasn't toiched it at all. That said, it is fairly tough - notable snap to it (even tho floppy).

I suspect not intentional - standard 300 year old north Devom construction - but my guess is, yes, it is something that was present in the cob when it was laid down (damp season for staw in 1725?) and the cob getting wet has activated it.

I don't *think* my hous is gonna fall down More of a curiosity really. Whatever it is, I doubt it'll survive trying to eat fresh lime putty