Earthen Floor Materials

In research I’ve done, psyllium husks are suggested as part of earthen floor mixes instead of straw.  I was wondering if chaff from milling grain could be substituted for a similar effect?  If so, would grain mills be likely to give bags of chaff away for a token fee?

If I recall correctly chaff can include things other than husks ... but if you were to sift the husks out then I don't see why you couldn't use any chaff from any grains to get the additive you seek.

What you would likely need to do is compare sizes of the two to make sure you are getting something similar to the replacement before jumping to the full process ... I really have no idea how much of a difference it would make if you used smaller chaff vs larger for example and it is something you might want to test. Also it could be chaff from one grain maybe absorbs water more than another and that could throw off any formulas you are using in creating the floor which require strict measurement.

As for getting it for free or cheap ... it is often used in cattle feed so it will likely have a price associated with it. I wouldn't let this stop you from asking. If you know the quantity you need call around and see what local sources will give you ;)

I suspect this might be best done in person as they likely have a waste bin of sorts with stuff they can't sell they would be willing to give you.

I live close to the Shawnee Mill's plant in central Oklahoma.  I might try to get there and ask.

As I recall from being a health nut decades ago, psyllium husk is used as a dietary fiber supplement. I believe it absorbs much more than its weight in water. Chaff may not have this property and so you may be comparing apples and oranges.

    What are you trying to get out of this husk/alternative product that you feel you can't get from straw? I've seen people use different materials, but I find most of this substitution is availability bases.
    I have made half a dozen different mixes of cob for different purposes, and have yet to not get what I needed from straw. If general size of material is what you're needing, then just shred the straw smaller with a weed eater. This is the method I use for all fine material like plasters and flooring. Academically, I have seen some scholarly articles reference how ones cob ferments prior to drying, thus adding strength and adhesive properties to the overall structure. This is the main advantage I can see in not using straw, and going for some other material that imparts a better fermentation evironment.
    The reason I think straw is great, beyond just tensile strength-availability- and reclaiming a waste product, is that it has less nutrients and sugars than hay and other alternatives. This means you are less likely to draw bugs into your cob looking for a free meal. If you do find that the husks draw bugs, then I read a post where someone was saying they blow torched the surface to destroy the available surface sugars and then sealed it. Good luck.

The idea behind psyllium husks in Earthen floors is that it supposedly makes a softer surface to walk on than clay/aggregate/straw, at least according to one of my cob handbooks.  Unfortunately, I don't remember which one and even if I did, it is packed away due to limited storage.  Yes, we have way more books on a variety of subjects than bookshelf space.

I'm right there with you on books. I had two full bookshelves when I put everything into storage to build our cob house. Now I can barely figure out where any of them are, and I have already bought enough for a small bookshelf since I stored everything.