Our House

This shows the fence staple holding the reinforcing wire in place. The post is wrapped with tar paper and the staple is nailed right through the tar paper into the post. It's not nailed in tightly so the fill can wrap fully around the end of the wire.

Because we’re nearly to the top of the reinforcing wire, our next step is to add another section of reinforcing wire above the current layer.  I’ll do that after this course has had a couple days to set up and I can strip off the forms.

This is the last course of eps-crete I can add without putting up some sort of scaffolding to stand on.  That’s a pretty nice milestone!

Today’s mix went really well.  We’re getting better at prepping.  We’ve switched over to using two half-gallon stainless bowls as measures.  They’re easier to fill AND easier to empty and clean.  We’re using one for the wet stuff and one for the dry which simplifies things greatly.  I also pre-measured and pre-mixed the paint and water so I had no waste and no mess during the eps-crete mixing.

Cleanup was much easier today and the bucket of warm soapy water used to wash us up during the build wasn’t needed.  That says a lot for the improvement in our method.  I’m hoping this wasn’t a fluke because last time we did this, it was a mess.

West end of wall Top down section

We’ve gotten another section of the wall done.  This one’s a lovely celedon green.  Wadly’s off to shop and have coffee with a friend today so I’m not expecting anything productive to happen around the farm.

Here’s the west end of the wall as well as a top-down cross-section so you can see how the eps-crete infill wraps around the post.  In the future, when I extend the building west, the foundation will be extended.  I should have wrapped the foundation around the inside of the post as well.  Hind sight.  I also should have done my electrical run and fastened the four-gang box to the 6-6-10-10 before putting the infill in place.  Again, hind sight.  This stuff is easy to shape after the fact so I can run a channel for the conduit and box before I build the next wall.  It just would have been much easier to fasten it to the reinforcing wire BEFORE doing the infill.  This is definitely a learn-as-you-go project.

Tedi supplying perspective

We have snow today for the second day in a row.  I’ve got the eps-crete forms moved and the paint mixed and I’m ready to put in another layer of eps-crete but . . . yeah, snow.

The picture shows one course of eps-crete in varying hues of red and white below two courses of gray.  The next two courses will be a nice celedon green.  The color is irrelevant. It’s free latex paint in the mix which is being elegantly and effectively recycled.  The wall is going to have a surface coat inside and out when it’s complete.  I plan to use lime plaster on the bedroom side and some form of exterior stucco on the sun porch side.  When I get to planning those coats I’ll start worry about color.

While I’m stuck inside I’m doing research.  I ran into this page on making lightweight concrete.  They use a mixer and the recipe results in a much soupier mix than what I make.  Theirs is pourable.  Mine isn’t.  It is common knowledge that, with concrete, the more water you add, the weaker the resulting product.  I’m not saying their recipe is bad, but the extra water would also not allow me to use the super light forms I’m built.  They pull the forms in hours, not days which I think has to do with my recipe using both latex paint and more eps in my mix.

My recipe and system works.  I like the result I’m getting with the mix I’m using.

2nd pour, a nice consistent bluish gray. First pour, yeah, not so much.

The first pour is red and four different shades of pink/white. The second pour is a consistent bluish gray.  None of the color will be visible as it all gets a skim coat.  I’m using lime plaster inside the bedroom and burlap dipped in cement slurry on the sun porch side.

I like this stuff. Epscrete is easy to mix, easy to work with and easy to clean up after.  It makes great thermal mass insulation.  That’s not as much as an oxymoron as you’d think.

This wall is ~6″ thick.  It is the dividing wall between the sun porch and the future bedroom, both conditioned spaces.  All the outside walls will be 10″ thick.

For reference, This much wall (~10″x12′) was mixed in 3½ batches.  I don’t think Wadly and I were out there more than an hour and a half and that included cleanup.

I did two things yesterday.  I ground 4 large black garbage bags of EPS and I opened old latex paint cans and combined them into a 5 gallon bucket ready for our next spate of wall building.

This morning I woke up with gurgley lungs.  At a guess I’m going to say it was grinding the EPS indoors.  We moved the grinder into the old shop so I could work regardless of the weather.  I could smell the fumes from the EPS as it was torn into little bits.  All the latex opening and dumping was done outside and the fumes weren’t noticeable.  My guess, the EPS grinding.

So, here’s my advice.  Either grind your EPS outdoors or wear a mask.  I’m wearing a mask next time I take on the grinding.

One more note.  I’m going to have to make a foam cutter to size the bigger pieces of foam for running through my grinder.  Per past research I’m going to use a dimmer switch (the kind you use for dimming room lights), a length of wire (can’t remember the type but will note it here when I find it) and a weight.  I’ll also need a couple lengths of wire and a wire with plug for electrifying the whole affair.  I’ll post pics as I go.

The forms in the picture in the previous article would not be sufficient for regular cement but work just fine for EPS-crete.  I built the forms by screwing particle board to the narrow edge of a 2×4 and fastening that assembly to the posts framing the EPS-crete wall.  I made the forms non-stick by stapling slip sheet (plastic coated cardboard) to the forms as a liner.  I should be able to take the forms apart and use the components for something else at some point in the future.

Most of these materials were what we already had.

We got a stack of 11″ wide x 8′ long pieces of oriented stand board left over from someone’s construction project. We’ve slowly been finding uses for them. We went from having a 5′ stack to having only a few left.  I’m a bit surprised they were used so fast given the awkward size and less than ideal material.  I don’t think we got them more than two years ago.

The 2x4s are 12′ long and were reclaimed from somewhere, though I can’t say exactly where.  Wadly probably took something apart.

The slip sheets are used on top of pallets to protect grain sacks and are free for the asking at our local feed store.  Wadly brings them home to lay on for vehicle maintenance.

I purchased the 6-6-10-10 wire last year for this project, it just took me a long time to get to it.  The method for grinding the EPS was the holdup.

The tie wire holding the two pieces of 6-6-10-10 together is recycled fencing wire we’ve had since the 80′s. The 6-6-10-10 reinforcing wire is held to the posts using fencing staples that were from . . . I think they came from Wadly’s father’s estate a couple decades ago. Maybe.  I know we’ve got way more than we will EVER use and we didn’t pay for them.

The tar paper’s fairly new . . . only a year or so old, I think.

Terry has a plastic barrel he puts in pickup and gets it filled with sand at the local concrete plant for $15.  Dry sand is something we always have on hand.

So, looking at the big picture, we bought the tar paper, reinforcing wire, cement and sand.  We just didn’t buy anything specifically for this project except the reinforcing wire and the cement.

First 10" of EPS-crete wall

I’ve got the EPS-crete wall started.  The forms come off today and they get moved up ready for the next layer.  So far, I’m liking both the process and the result.  It’s dead easy to mix, light to shovel, doesn’t require herculean forms and is easy to press into place.

The reinforcing wire isn’t necessary for EPS-crete used as post-and-beam infill, but the lower part of this wall will be backfilled for the first foot plus a bit, so the wire’s insurance.  When the foundation was poured I included old bolts, drill bits and big bent nails sticking up down the centerline to which the reinforcing wire has been fastened.  This is light duty construction.  The posts do all the “hold the building up” work.

Before I give you the mix recipe, here’s how I prepared the EPS for mixing.  You’ve already seen my foam shredder/grinder.  I transferred the ground EPS from the shredder box into tall kitchen garbage bags.  Into each bag I added between 2 and 3 pints of warm water to which I’ve added a squirt of dish soap.  The dish soap is a surfactant to break the surface tension on the EPS.  Mix the soap to water ratio as if you were planning to wash dishes with it.  Tie the top of the bag closed.  The bags I use have four “ears”.  I tie them diagonally in half-bows I can undo.  The goal is to keep the EPS and water/soap mix inside when I start rolling the bag around to distribute the soapy water.

The longer you can leave the mix in the bag (and even in the sun to help reduce the soapy water’s viscosity and allow it to spread) and the more times you can rotate it to get the liquid evenly distributed, the better the result.  Otherwise the water drains to the bottom without evenly coating the ground EPS.

The beauty of this method is, when it comes to the point where you’re mixing the EPS-crete, the ground foam is quite controllable.  It doesn’t float around, blow around or stick to anything via static electricity.  You can measure and mix it without getting it everywhere.  In other words, it ends up in the mix instead of all over you, the ground, the equipment, your other ingredients and your helpers.

Here’s the mix part.  Bear in mind this is subject to change based on how this wall  performs.

• 2 parts cement
• 2 parts sand
• 1 part water
• 1 part recycled latex paint
• 16 parts ground EPS  (This is the most flexible part.  More or less depending on what you’re doing.)

I made my first batch in a cement mixer but it’s more work any way you look at it.  See my note at the end regarding using the mixer.  Lucky for me, our cement mixer stopped working after the first batch.  <wince>  The cement mixer came to us used with a history of being poorly maintained.    In addition to a new cord, the intermediate drive shaft needs rebushed and the central pinion (shaft fastening the barrel to the frame) needs replaced.    I’ll fix it but it’s going to be a major job I don’t want to make time for right now.

After losing the use of the cement mixer, Wadly mixed the remainder of the batches by hand.  It’s really easy to do using a short handled shovel.

For measuring, I’m using a plaster straight-sided plastic pitcher.  The shape, material and fact that it came pre-equipped with an integrated handle means the plastic pitcher works awesomely well.  It would be nice to have one for each type of ingredient.  Hmm.  It might be worth hitting the dollar store to see what I can find.

Because this recipe is by parts, it’s an easy recipe to duplicate.

1. Give the bag of EPS a couple of flips to distribute any water that’s settled out.  Measure the ground EPS into the wheelbarrow, leveling it out.
2. Sprinkle the sand over the top.
3. Sprinkle the cement (be careful not to create dust and yes, you should be wearing a mask) over the top of that.
4. Mix the latex paint and water together.  I use an old paint can to mix this in.  Stir thoroughly.  I should use a 5 gallon bucket and premix a whole bunch at once.  Next time.
5. Drizzle the paint and water mix over the top.
6. Shovel mix until everything is completely combined.  Watch for and break up any paint balls.  I would like to have a drill mounted stirrer for combining the paint and water to help avoid this problem.
7. Shovel the mix into the form.  It’s fluffy so you’ll need to pack it in you will have voids in the project.  If one person shovels and one person packs, the work goes quickly.

I’ve combined ingredients in a different order but the steps above produce the best result.

This mix isn’t runny like regular cement.  It’s wet enough stay in place when you pack it into the form and not so wet as to have any of the parts separate out.  If you make it too wet, you’re doing two negatives things; you’re weakening the concrete and making it wet enough to allow the EPS to separate out.  You’re after a mix that’s wet enough to stick together when you pack it and dry enough to have zero slump.  If you try to pack it and it crumbles, it’s too dry.  If you pack it and moisture comes out ANYWHERE, it’s WAY too wet.  If your mix is too wet, reduce the amount of water you’re adding to the bags of eps.  If you reduce the amount you add when you’re mixing, you’ll get more paint balls.

From experience I’m going to say you will have to scrape the sides of the concrete mixer if that’s what you use to mix.  This stuff, because it’s so light, will stick to the sides and not mix thoroughly.  There’s not enough weight to the mix for it to scrape the sides of the mixer for you.  Be prepared to stop the mixer, scrape the sides and restart.  Success depends on thorough mixing.

Once the mix has set, spray it twice a day with water to help keep the cement hydrated so it will cure strong.

Set up and tested 1 1/2" pvc to fill the gap where the edges of the nail laden pvc don't meet. Motor installed, top deflector installed, ready to go.

I’ve got the foam shredder prototype working. The roller center is a solid stainless conveyor roller from a fresh produce processing plant.  My brother was going to add short spikes to it for my shredder drum but he ran out of time about five spikes into the project.  The pulley is from a box of stuff we collected somewhere and the key to hold the pulley on came out of a drawer.  The motor goes on the cement mixer and the belt was hanging on the shop wall.  The gray is aged black pvc pipe left over from some other project. I’ve drilled a grid of holes 1/2″ apart and stuffed the holes with 3/4″ roofing nails that were a box that went from my dad’s estate to Dan and then to us.

I started with just the pvc filled with roofing nails.  I was going to add a central shaft and pour it full of concrete but Dan sent the roller with bearings attached.  It seemed smarter to split the pvc and slide it over the roller rather than try and come up with a shaft and bearings.  There’s a trick to holding all the nails in place as you work.  If you need to know, ask me.

I probably don’t need the pvc filler in the blank spot, but I’d rather do what I can to ensure consistency in the particle size.  When I tested it without the pvc and while rotating the wheel by hand I ended up with occasional bigger chunks when the foam was caught by the blank space.

The last picture is the shredder ready to go.  The base/box is one of a pair built to act as supports for Dan’s lathe.  The bungy cords hold the door on to keep the shredded foam in.  The deflector is a cut down plastic waste basket that had multiple splits at the top.  I used a box knife on it to reshape it for this task.  It’s held down by gravity.  If that doesn’t work, I’ll figure out how to stabilize it.

To dispense the foam I’m going to flop the box onto its left side, undo the bungies and shovel the shredded foam into the mixer or storage container.

So far I have exactly zero dollars and a couple hours in this project. I think that’s pretty good for the result.

I’ve got two big pieces of  foam ready to grind.  Once it cools a little off a little bit outside I’ll shred them.  I’ll measure the size of the pieces and time how long it takes to shred them.  If I can get some foam shredded today Wadly and I can mix up a batch of eps-crete tomorrow.

Result with concrete lath mounted over original wood chipper screen.

I finally got to rescreening the wood chipper to use it as an EPS grinder.  It looks like it will work okay.  The foam pieces have to be small enough to fit in the hopper, but once introduced to the blades, the foam gets ground fine enough to do the job.

We’ll load the chipper into the back of a stable vehicle so we have a drop for mounting a collection bag.  I will be making it out of sun shade cloth if I can’t find a collection bag locally that will work.

Size range in wood chipped foam Bearcat wood chipper

I borrowed my brother’s wood chipper to test chipping foam.  I think wood chipping foam will work if a screen is added to the chip exhaust to keep the larger pieces of foam inside the chipper until they’re reduced sufficiently in size to exit the screen.   The unscreened size ranges from 3/4″ to big dust.  Adding a screen (maybe concrete lath?) may be all it takes to get the right size for making EPScrete.

Dan’s machine is a fairly expensive heavy duty chipper.  I can’t speculate on what another chipper’s result would be.