Picture of I Love Papercrete
Papercrete??  What’s that?? 

That’s the response I always get when I’m describing my favorite building material.  Not surprising since it occupies a spot in that backwater known as ‘alternative building materials’.  Papercrete is just what it sounds like actually.  It’s concrete made with paper.  I tell people to think of it as industrial paper mache.  It’s inexpensive to make, amazingly sturdy, lightweight and insulating.  

I didn't invent it but I have played with it quite a bit over the past several years. In this Instructable I'm going to go over a little of the history behind it, exactly what it is and how to make and use it.  By the time we're done you'll love it too!  
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Step 1: A Brief History of Papercrete

Picture of A Brief History of Papercrete
Papercrete was originally patented in the 20's.  The patent lapsed because it was too easy to make on your own and the patent holder wasn't able to make any money off it.  It really came into it's own as a building material in the 80's.  Eric Patterson and Mike McCain are widely credited with independently inventing (rediscovering) it and actively developing techniques and machinery for working with it.   

I discovered papercrete in the late nineties.  I used to own a magazine distribution company that specialized in small press and unusual magazines.  One of the titles we carried had an article about people who were recycling newspapers and building with papercrete down in southern New Mexico.  It was a total off the grid hippie dome sort of scene.  The domes weren't my thing but I was captivated by the material and the process of making it.  I saved a copy of that magazine and told everyone I knew about it. 

It was especially appealing to me because of all the waste involved in magazine distribution.  All the unsold magazines would be returned to me and I would have to pay to have them hauled away for recycling.  Turning them into building blocks would have been a perfect solution.  Unfortunately at the time I didn't have a place to experiment with building projects so eventually the papercrete article went into storage and the idea went on the back burner.  

My biggest obstacle was the mixer.  To make papercrete you have to be able to grind up paper… lots of paper.  In order to do so you need a mixer capable of shredding paper.  A regular cement mixer won’t shred the paper it will just stir it around.  Luckily for me, Mike McCain had already invented an ingenious papercrete mixer that you tow behind a truck.  You just throw everything in and drive slowly for about a mile.  When you’re done you have papercrete slurry ready to be cast into something.  
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This looks like it would be a excellent material to build this

allan.sivell2 months ago
Quick question. It may have been ask already, but what do you do to water seal papercretw? You mentioned it can not be buried because it will break down. You also said it soaks water like a sponge. What do you do for out door use. Can you use thompsons water seal or some other concrete water sealer.


I am working on a building material that is far more versatile and costs from. £0.00. Yes thats right you can get the material for nothing. Some places charge I am going to use it for pre casting wall/door/window panels. Anyone interested email:

HelenaTroy7 months ago

I first found out about papercrete while searching for an alternative to hypertufa (I'm visually impaired and didn't fancy the chance of inhaling any of the fine cement dust because I'd need to be close), but your Instructable really explains it, thank you. Not that I want to make a house! I've been wanting to do craft casting, small items, and this encourages me to have a go.

ledshed1 year ago
Brilliant, but I think the amount of rain we get in the UK would make it impractical.

not really just use a water based breathable spray on coating.

Here in western Washington state we get lots and lots of rain. The best siding material for our houses is Hardi-Plank, which is a paper fiber/Portland cement composite. It's all a matter of how good a job you do of shredding the paper and mixing its fibers into the cement matrix. Done properly, the stuff will last for a geoduck's lifetime.
I live where wind chills of -40°F are normal. Some years we have 10 or more feet of snow. I have two questions. 1 - if filled full of dirt to begin with will raised garden beds withstand that kind of weight? 2 - I will only be able to make a few pieces at a time. How warm does the outside temps have to be for these things to cure?

abut the same 4 a normal concrete block.

spike3579 (author)  cbochman anderson1 year ago
I tie the back of the papercrete blocks together with a strip of galvanized steel which is screwed to the blocks. This helps keep the dirt from pushing the blocks over. As far as snow I think that all the snow around the bed would provide some sort of support. I've had three feet of snow with no I'll effects.

As far as temp. I'm in New Mexico where it is quite warm and dry in the Summer. I usually cast blocks in June-August with temps in the 80's - 90's. The blocks dry in a week or so. They will cure at any temp above freezing but may take a long time to fully dry. One thing to do is make blocks one season and stack them to dry with some sort of cover and come back the next year to build with them. I've done that with larger projects where it takes a while to get enough bricks to build a building.
davhi81 year ago

I am using a different size tank for my mixer. Can you give me an estimated amount of water you use? Also, can I add wood shavings from a planer to the mix?

Thanks in advance!


spike3579 (author)  davhi81 year ago

I'm using about 150 gallons of water to one bag of cement to 75 lbs paper. I think it would be perfectly fine to add wood shavings though you may need to add more water if the mix is too thick. Don't skimp on the paper since that's what's holding it all together. A little experimenting will dial in the perfect mix.

Thanks a million Spike! I will post photos when I finish my mixer and any tech notes I may come up with.

spike3579 (author)  davhi81 year ago

Awesome! Looking forward to it.

ChinaMike1 year ago
I really enjoyed your project. I found it first on Mother Earth, then came here via a link. The only thing I would criticize is calling this a yurt. Just because it is a round dwelling with a self supporting roof does not a yurt make. The true definition of a yurt is a completely modular dwelling that can be taken down and reassembled. You could rename it a yurt-like building, but this is like calling an A-Frame house a giant pup tent!
The mixer thing is brilliant. I plan to move to Austin soon (I am currently in Hawaii) and will be purchasing some lake land property and am looking at all kinds of simple yet structurally sound building ideas. Yours is definitely at the top of the list!
Spike, I apologize if you covered it somewhere but I couldn't find it - did you mortar between the blocks? It looks like you did... what did you use? If it is traditional cement mortar, how well does it bond to the blocks, especially over time? Some of the comments about the papercrete absorbing moisture and expanding/contracting similar to what wood does as humidity levels vary makes me think that traditional mortar would eventually separate from the papercrete.
spike3579 (author)  georgelstuart1 year ago
I used papercrete to mortar the blocks together. You can also use it as a plaster as well. It adheres really well to the blocks. Cement mortar doesn't stick well at all.
jack85591 year ago
Do you need to spray poly or something else over this after it dries to make it more waterproof or does it not swell at all when it gets wet, or will poly or other product hold moisture in and make it deteriorate faster? How about anchoring it to the foundation, is it necessary, and if so, what would be the best method- threaded rods through the wall down to the foundation? How deep and wide does the foundation need to be, 6 inches wider than the blocks and a foot or more thick? This looks like a really good product you are making, I just want to know more about it so I can build stuff with it and know how well it will withstand the elements in central North Carolina- high humidity all year long, some snow in winter and 100 degree days in the summer. Sometimes it will rain for days in the winter as well. Any input there for me?
spike3579 (author)  jack85591 year ago
Putting an outer coating on the papercrete is probably a good idea for where you live. There are bunch of ideas/suggestions in the comments. I'm opting for large overhangs on the roof and maybe stucco someday. My foundation is only 1' wide and 6" deep w/ two rings of rebar inside. I didn't tie the building the foundation but threaded rod or J hooks would be the way I would go. If it were me I would make a small shed or other starter building first to see how it holds up in the NC climate before I invested a bunch of time in a major building project.
One of the best - I love this instructable
can you actually give the proportions the way it is mentioned in cement mortar
like 1:2; 1:4 etc?
spike3579 (author)  shuja.shaher1 year ago
I get 13:1:0.75 water,cement,paper by weight. Your results may vary but it's a starting point.
rgagne21 year ago
i am prototyping natural fiber reinforced garden and patio-ware in limecrete. burlap, weldbond, perlite, portland, builders lime, foam and hemp hurd are in the mix. papercrete and hempcrete are not recommended to be in direct contact contact with earth yet you are making raised beds and planters..for precast pots and such my mix needs to be pourable so i treat the burlap and hemp hurd with acrylic cement binder, (weldbond) . this makes the fibers not soak up water and the mix retains good workability. your planters show some breakdown on soil side after three years... in desert climate. i have no idea how long my pots will last, but 3 years seems a bit short for commercial product...any thoughts?
spike3579 (author)  rgagne21 year ago
I have the biggest breakdown issues where the PC is buried underground. Treating the earth facing side I imagine will address most breakdown issues for a planter. Really you would just have to test it to see. PC is great as a castable material. It molds really nicely.
The best part about this article is the mixer. Genius.
mknoop181 year ago
I love you, thank you
Replicator1 year ago
Papercrete similar to timbercrete IS a brilliant building material. Having worked at timbercrete for 2 years and personally comparing different materials against it..... i would never build with anything else.
chuckyd1 year ago
Sorry, but that papercrete just does not seem to be an efficient building material, nor does it seem to be a good choice.

First, something made without any quality control cannot be expected to be consistent. I looked at other websites about the material and saw nothing about compressive strength.

Anything that absorbs and releases moisture also changes size, creating cracking and settlement issues.

The combination of cellulose, water, and warmth is an incubator for mold and vermin.

Earth based blocks, such as abobe and cobe, even thought some contain straw and other organics, are a much better solution, and are by far greener. Look up what is required to make cement.
shortw chuckyd1 year ago
'' Earth based blocks, such as abobe and cobe, even thought some contain straw and other organics, are a much better solution, and are by far greener. Look up what is required to make cement. ''
With a lot of such structures that I seen, they still use cement to get the extra strength and to avoid the structure to crumble with the present of moister and water.

Red bricks, gray cement blocks, wood, drywall and plaster and many more can and will absorb water and moister and they are used in everyday building constructions.

If someone wants to moister and / or water prove such materials, all they have to do is paint it with the right paint for the application or use other protective materials such as a vinyl siding for example.

spike3579 (author)  chuckyd1 year ago
Ahh....a wealth of opinions makes the world a much more interesting place.
kanemaui1 year ago
Well, actually Spike, THANK YOU!! GREAT stuff here. I live between Maui and Southern Oregon and have wanted to build some simple out buildings on both properties for some time now. Though CMU is DEF a possibility, I LOVE the similarities and flexibility with the Papercrete approach because I'm NOT limited to the dimensions (AND cost) of traditional CMU's. Though you mention the R-values of PaperCrete Units (PCU's), let me ask: How are the thermal qualities in WARM weather. I'm pretty much assuming they are similar in the 'reverse', keeping the interior cooler when it's hot outside ~ ~ ~

Also, can you provide a more specific 'recipe', ie, %concrete to %paper to %plastic. You mentioned about 75lbs of paper to 95lbs of cement, which is about 45% paper and 55% cement. I guess I'm asking this: What would you consider to be the upper range of % of paper content? Could the ratio be 50/50 by chance. Here's another assumption I'm making: The 'paper' one adds to the mixture could be pre-shredded if one were to acquire a source of that nature. Since you mention you get 45 blocks with a dimension of 8″ x 12″ x 5″ per block per 'hopper', with a mortar bed that's roughly 2 blocks per square foot and 22 square feet per hopper. NICE!!!

To address a comment about 'bottles' and 'stack wood': IF you were to incorporate these 2 different design features into a Papercrete building you would need to assure that the 'joint' between the 2 different building types adequately addresses the load differentials that would be an inherent part of the structure. For bottles, it would be BEST if you build a lintel 'header' over the are you anticipate installing a bottle section. Glass bottles are NOT inherently strong NOR are they 'structural' IN ANY WAY. They are WAY too brittle, and just imagine what a PIA (Pain in the A**) it would be to replace one that broke from a poorly planned installation. If you build a lintel over the area where you intend to install a bottle section, that lintel will carry the weight of the Papercrete blocks above and therefore (HOPEFULLY) prevent pressure cracks/breakage on your bottle section.

With 'stack wood', there is another set of issues related to a combined style of building in that 'stack wood', unless TOTALLY dry with optimum moisture content (roughly 3%) and dimensionally stable, will shrink, warp, crack, and check. It is IMPERATIVE that you structurally segregate (expansion joint material) the stack wood from the Papercrete so that any of the wood's dimensional instability can be isolated from the rest of the Papercrete blocks OTHERWISE you'll lose structural integrity in the Papercrete blocks as well as the stacked wood ~ ~ ~
robertc1231 year ago
what is the mixing ratio for smaller batches than a stocktank full?
spike3579 (author)  robertc1231 year ago
Scroll through the comments. It's covered a couple times.
kanemaui1 year ago
One small suggestion: 'Cement', at least the 'Portland' kind, is composed of the following materials:

Lime or calcium oxide, CaO: from limestone, chalk, shells, shale or calcareous rock
Silica, SiO2: from sand, old bottles, clay or argillaceous rock
Alumina, Al2O3: from bauxite, recycled aluminum, clay
Iron, Fe2O3: from from clay, iron ore, scrap iron and fly ash
Gypsum, CaSO4.2H20: found together with limestone

When it comes into contact with water it begins to form a crystalline structure which gives it its inherent 'hardness' and building qualities. Spike mentions he removes the molds for the bricks IMMEDIATELY allowing more 'air to circulate' for, I assume, the quicker availability for the bricks to be used in the project.

BIG PROBLEM HERE: Quickly drying cement does NOT allow for adequate crystal formation in the cement therefore a weaker brick SOMETIMES not curing at all which subsequently will cause it to crumble.

SUGGESTION: AFTER stripping the molds from the bricks, cover the bricks with gunny sacks OR ANYTHING that can hold moisture, ie, rags, towels, sheets, etc. There's even a product you can buy just for this purpose, but since economy is a driving factor here, the cloth-type coverings work just fine. The trick here is to NOT LET the CLOTH dry out, EVER! Afterwhich, over the next few days, better if it's weeks, maintain the moisture on the gunny sacks which will allow the crystalline structures to form which will result in a brick harder and stronger than the Hinges of Hades and MORE moisture resistant to boot. IF POSSIBLE, allow the bricks to 'cure' for a month and you'll find your bricks harder and stronger than even Thor could destroy.

I once did a concrete job in La Costa/Carlsbad California where we were able to actually bury a house slab UNDER WATER for 30 days. When we uncovered the slab and had to make saw-cuts for some revised plumbing, our Demolition Contractor said he'd NEVER seen concrete that hard and had to blow through more diamond bladed saws than he originally bid the project for. We were glad to compensate him for the additional costs because he did a GREAT job ~ ~ ~ The slab didn't even crack and the FIRST RULE of CONCRETE work is: "Concrete is GUARANTEED to crack! EVERY TIME" ~ ~ ~
spike3579 (author)  kanemaui1 year ago
Great comment thanks!
Lots of good info.
shades of THE MOTHR EARTH NEWS!!! Why not collect empty bottles, and use the stacked cord wood method, only using bottles?

In MEN, they showed how to build using cord wood in a structure as "blocks" , the entire structure is stucco'd on the outside and made waterproof with polymers (or waterproof stucco cement. Keep open ends inside the structure so as not to trap water, You could leave a section or two more exposed inside and outside to allow a skylight effect.

None of this is my idea look around on the net and go to MEN to view and buy old issues. (http://www.motherearth{ take this out }

A thought on caustic and paper. If the paper all decayed and there is enough cement, would you then have a nice porous sponge, that is strong?
hohum1 year ago
A bunch or stuff:

1. i want to make one, as far as compressive strength, i'll drive in coated rebars and tie them to the roof
2. you mention the papercrete absorbs water, could you coat the outside w/ cement?
3. very nice ible- very informative
4. you said it has been a year now, with no problems, good enough for me.
5, i'd put in few round holes for windows,
5.5 one could totaly live in this 'yurt'
6. @ how long did this project, just building part.
7. thanks very much for posting

spike3579 (author)  hohum1 year ago
There are a bunch of waterproofing options discussed in the comments.
Windows would be a nice touch. Mine has a big skylight which adds a nice amount of ambient light to the space. I can't really give a good estimate on the amount of building time since I did it in fits and starts mostly by myself. I would say one motivated person could easily have a habitable structure in one building season.
Good luck w/ your project. Post pics!!
onebigelf1 year ago
I wonder if it would be possible to work out the form and cast complete geodesic dome triangles? Cast the sections with a taper so they just fit together without the usual brackets.
grt571 year ago
Nice job... thanks
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