Light straw/clay pallet shed

So we spent two weeks working on this little shed so there would be somewhere dry to store our tools while we're in Florida for the winter.

We used cedar posts for the framing, 36"x36" pallets for the "forms", and a rammed light straw clay infill. We'll finish filling in the tops of the walls and do an earthen plaster this spring.

We had fun at the local thrift store finding interesting objects for windows.

We're also doing a trial run of a living roof when we get back. We only had time to tarp the roof. This will be a small guest cabin when it's finished.  

Wow!
Thank you for the pics.

What a fun project!

I think it is interesting to use pallets as your forms. Is there a minimum width earth rammed walls need to be or is it only if it is a free standing type of wall? I don't know anything about earth building but this gives me a bit of inspiration for a smaller scale project.

Timothy Norton wrote:What a fun project!

I think it is interesting to use pallets as your forms. Is there a minimum width earth rammed walls need to be or is it only if it is a free standing type of wall? I don't know anything about earth building but this gives me a bit of inspiration for a smaller scale project.

The straw-clay isn't structural, it's just infill.  You can do this with traditional framing as well, but the pallets were super cheap and fast to get up.  The cedar posts take all the weight of the roof and stuff.  I got the idea from the palletable cobin videos.  They use regular flakes of straw and add a lot more boards to the pallets.  Then you cob over them and you can't even tell what they're made of - they just look like a super cute little building.  I decided that since pallets cost money and are a pain to pull apart, we'd just use the light-straw clay which takes plaster wonderfully.  Not sure if we saved much time (the straw-clay takes a bit, but once we got everything down to a science it went faster).

Some things we learned:

When you first mix the straw and clay, it seems like it is never going to work - but it always does once you get it tamped in the wall and pull off the plywood forms.

It's best to use all the same size pallets if you can.  I like the 36"x36" because they're easy to handle.  Obviously you can cut and alter pallet size, but it takes time.

If you're super picky about square...this building method is going to be a challenge for you (just ask my husband).

It is concerning that pallets cost money where you live.

Bad economic conditions spread. I will probably go gather up  all the pallets I can this weekend.

Thanks!

Jeff Lindsey wrote:It is concerning that pallets cost money where you live.

Bad economic conditions spread. I will probably go gather up  all the pallets I can this weekend.

Thanks!

You can definitely find them for free here too.  

We bought them for the convenience of having them in one place that's close to home and getting them all one size.  They are $3 each.  We figured that by the time we drove around picking up pallets, we'd pay more in gas.

Ah, good to know.
I use so many pallets, I am always concerned about the free river of such convenient forms drying up.

Thanks, and again, that’s a great start on that “shed”

How did you mix the clay and straw?

J Hillman wrote:How did you mix the clay and straw?

It took a little time to get it down, but here goes:

First I spread 4 flakes of straw onto a 6x10 tarp, making sure that there weren't any clumps at all.  At first I spread it thin, but I learned it's better to have a flattened pile in the middle.  You don't want to pour the slip on the tarp since it just sticks to it.

I screened our subsoil (which is mostly coarse to fine granite sand with a fair amount (30%ish) of clay) to break up chunks and get out big roots.  Then I filled a 5 gallon bucket just under half full of water and added a 2 gallon bucket of screened soil, mixing it with a sheetrock mud paddle.  The finished slip was the consistency of a melty milkshake.

Then I dipped out the slip with a 2 quart container and poured it over the straw, trying to cover as much as possible.  Stir it right before each dip so the sand won't just sit on the bottom.  Once I had 3/4 of the slip on the pile, I pulled (don't push, it's hard on your back) the pile halfway over, folding the slip in the middle.  Then I took about half of the remaining slip and poured over the bottom.  There's usually some dry straw at the ends of the roll.  Grab that and throw it in the middle along with any straw in the pile that looks particularly dry.  Then pull your tarp the other direction over the dry straw.  Pour the rest of the slip onto the pile (there's a lot of sand in this last batch, but it's fine), once again pulling the dryer stuff from the ends and throwing it in the center where you will be pulling the straw.  

Continue rolling the pile back and forth in the tarp, pulling the ends and putting them in the middle so they don't overflow the tarp.  Every once in a while, pull the whole pile apart and throw it into the center of the tarp to check for dry spots.  It should take 6 - 10 rolls to get it coated - sort of like a light salad dressing.

Don't worry if it doesn't seem too sticky once coated.  At first I wondered if it would even work, but once you stuff it into your form and tamp it down good, the clay sticks everything together.  We usually left the form on for 45 minutes or so after tamping, but you can take it right off if you aren't filling and tamping right above a freshly tamped area.

This is quite forgiving.  Sometimes the slip was a little thinner, sometimes a little thicker.  They all seemed to work just fine.  

I hope this is clear.  Please don't hesitate to ask for clarification on anything I might have missed.

Sherry Willis wrote:

J Hillman wrote:How did you mix the clay and straw?

It took a little time to get it down, but here goes:

First I spread 4 flakes of straw onto a 6x10 tarp, making sure that there weren't any clumps at all.  At first I spread it thin, but I learned it's better to have a flattened pile in the middle.  You don't want to pour the slip on the tarp since it just sticks to it.

I screened our subsoil (which is mostly coarse to fine granite sand with a fair amount (30%ish) of clay) to break up chunks and get out big roots.  Then I filled a 5 gallon bucket just under half full of water and added a 2 gallon bucket of screened soil, mixing it with a sheetrock mud paddle.  The finished slip was the consistency of a melty milkshake.

Then I dipped out the slip with a 2 quart container and poured it over the straw, trying to cover as much as possible.  Stir it right before each dip so the sand won't just sit on the bottom.  Once I had 3/4 of the slip on the pile, I pulled (don't push, it's hard on your back) the pile halfway over, folding the slip in the middle.  Then I took about half of the remaining slip and poured over the bottom.  There's usually some dry straw at the ends of the roll.  Grab that and throw it in the middle along with any straw in the pile that looks particularly dry.  Then pull your tarp the other direction over the dry straw.  Pour the rest of the slip onto the pile (there's a lot of sand in this last batch, but it's fine), once again pulling the dryer stuff from the ends and throwing it in the center where you will be pulling the straw.  

Continue rolling the pile back and forth in the tarp, pulling the ends and putting them in the middle so they don't overflow the tarp.  Every once in a while, pull the whole pile apart and throw it into the center of the tarp to check for dry spots.  It should take 6 - 10 rolls to get it coated - sort of like a light salad dressing.

Don't worry if it doesn't seem too sticky once coated.  At first I wondered if it would even work, but once you stuff it into your form and tamp it down good, the clay sticks everything together.  We usually left the form on for 45 minutes or so after tamping, but you can take it right off if you aren't filling and tamping right above a freshly tamped area.

This is quite forgiving.  Sometimes the slip was a little thinner, sometimes a little thicker.  They all seemed to work just fine.  

I hope this is clear.  Please don't hesitate to ask for clarification on anything I might have missed.

Thanks for the details.  How you separated the clay from the sand one bucket at a time with water was especially helpful.  I have been learning about using light straw clay recently and had a few  half thought out ideas on how to get rid of the sand from my heavy clay soil to have a clay slip.  Knowing how you did it helps a lot.

J Hillman wrote:

Thanks for the details.  How you separated the clay from the sand one bucket at a time with water was especially helpful.  I have been learning about using light straw clay recently and had a few  half thought out ideas on how to get rid of the sand from my heavy clay soil to have a clay slip.  Knowing how you did it helps a lot.

We didn't actually separate out the sand.  We used it sand and all it it worked just fine.  You could separate it out, and I would for plaster or something like that, but for light straw-clay, I wouldn't go to the extra work unless there just isn't enough clay to make everything stick.  I would test it as it.  I discovered that it doesn't feel like it's going to stick together until you stuff it into your form and tamp it down.  When the forms come off - there's a solid wall - Like Magic!!

Sherry Willis wrote:

J Hillman wrote:

Thanks for the details.  How you separated the clay from the sand one bucket at a time with water was especially helpful.  I have been learning about using light straw clay recently and had a few  half thought out ideas on how to get rid of the sand from my heavy clay soil to have a clay slip.  Knowing how you did it helps a lot.

We didn't actually separate out the sand.  We used it sand and all it it worked just fine.  You could separate it out, and I would for plaster or something like that, but for light straw-clay, I wouldn't go to the extra work unless there just isn't enough clay to make everything stick.  I would test it as it.  I discovered that it doesn't feel like it's going to stick together until you stuff it into your form and tamp it down.  When the forms come off - there's a solid wall - Like Magic!!

I guess I misread your original response to me.  I though it said you let the sand settle to the bottom, when you actually said the exact opposite of that.  I Think my soil would have too much non clay in it to use it as it is.  My thought was to mix it like you did but then let the heavy stuff settle out and leave it behind.

J Hillman wrote:

I guess I misread your original response to me.  I though it said you let the sand settle to the bottom, when you actually said the exact opposite of that.  I Think my soil would have too much non clay in it to use it as it is.  My thought was to mix it like you did but then let the heavy stuff settle out and leave it behind.

I'd try it as is first.  Our soil has a LOT of sand, some the size of fish tank gravel.  No sense doing extra work.

We've been back at the place for a couple of months and working like crazy!  The thing is, when I have time to post, I'm not doing anything and when I'm doing stuff, I don't have time to post.  Here are some pictures of the progress on the light straw/clay - pallet shed.  We decided on a moss roof as it's heavily shaded.

I like those big eaves.  They should help keep the walls dry and protect your cob.

J Hillman wrote:I like those big eaves.  They should help keep the walls dry and protect your cob.

That's the hope. We're planning on putting a stacked stone "foundation" up as well which should protect from ground splashing.  What water isn't soaked up by the moss will go into a rain barrel.  

We have about $500 in the building so far, including a little wood stove.

What a wonderful project!
Can you describe the details of the living roof!

William Bronson wrote:What a wonderful project!
Can you describe the details of the living roof!

Thank you!

Please understand that we're making this up as we go, so I'm sure there will be failures and adjustments.

We used rough cedar slabs for the decking.  Since they don't meet at the edges, we got some white sheets from the second hand store and made them the next layer. Then we put a thick layer of cardboard to even out the surface and protect the 20 mil pond liner that waterproofs the whole thing. We added +/- 2" of soil and then are harvesting moss from the river nearby.

Before we put the soil on, we checked where the water flowed on the liner. It actually went where we wanted it to!! So we cut a hole and lined it with roof flashing tape to seal it. Then we put 1/4" hardware cloth, a layer of screen and covered it with soil and moss.We were hoping this would be sufficient for a drain, but we had heavy rains yesterday and it isn't draining like we'd hoped. I think we'll pull the soil out and fill over it with gravel to make it more permeable.

We covered the moss we got done with loosely woven burlap landscaping fabric, but we've decided to trade that for black poly bird netting. It will be less obtrusive, still stabilize the moss while it gets established, and we can just leave it up there.

Sorry for the book... hope this helps.

Thank you for your generous response!

The real problem with working on stuff is that it's hard to find the time to post about it.  I definitely need to do a better job of that!

Anyway the "Hovel" is fully functional, if not completely finished (is any building project?).  Here's a construction video I put on my YouTube Channel: