DIY Shotcrete

DIY Shotcrete
June 10, 2013
Sammy

DIY shotcrete is achievable for a hobbyist, owner/builder or a contractor. It is all about the speed of delivery you want to accomplish. The best advice ever shared with me about shotcrete and pumping concrete is to choose the equipment needed as a package, because each set up works best at a specific scale. I have also learned that pumping is an art. It requires practice, skill, and dedication to become efficient at it.

Before getting started, decide if you want to spray ready mix or site batched shotcrete. For most DIY shotcrete, you will be setting up for site batching/mixing the shotcrete mix. With site batching, a good scale is 0-5 yards per hour (YPH). In this range, you can cover a lot of structure in a short time, and with very little investment compared to the larger volume jobs.

Once you have decided on the delivery speed, you will want to match your compressor to the job. The compressor does the work of throwing the shotcrete from the shotcrete nozzle onto your target. More air is better for both the spraying, and also compaction of the shotcrete.

DIY Shotcrete. 0-5 YPH . Through the years of working with shotcrete, I have moved away from using shotcrete pumps, and have gone toward smaller and less cumbersome tools for shotcrete work. My increasing  interest in thin shell structures use less shotcrete and less muscle. A good example of this are Stuctural Concrete Insulated Panels (SCIPs). As I have gotten older and less interested in packing heavy concrete hoses around a job site, lighter weight and less work have become more important. Many our structures are designed to be 1″ thick shotcrete or thinner. Some people raise an eyebrow when I tell them I aim for 1 yard per hour. When I explain that with only a Stucco Sprayer, instead of a pump, we can shoot more than 324 square feet per hour on a SCIP structure. Most people start to see the benefit.

Mike describes his Stucco Sprayer as a mini-shotcrete pump without the delivery lines.

A good compressor for this 0-5 YPH range can be a 5 hp 220 volt electric or a 6.5hp or larger gas powered compressor. 7 CFM minimum to 19 CFM at 90 PSI. More air is better. This scale works great for a 1 to 6 man crew. Projects this size are shotcrete houses, faux rock projects, vertical concrete, ferrocement water tanks, and plastering jobs. The stucco sprayer is also a great tool to use in your pump package when setting up for larger scale production would be inefficient.

DIY Shotcrete. 5-10 YPH In this range you have choices. Ready mix or site batched shotcrete is an option. When you step into this rate of production, the costs and complexity take a dramatic jump because you will need a larger mixer, a pump, tow behind compressor and a skid loader. It’s not too difficult to take a big jump in productivity, if you are well organized. The most versatile pump in this range is a peristaltic pump from Blastcrete (see photo below). With the peristaltic pump you can do bulk work and also thin shell. A 1.5 hose package and matching shotcrete nozzle works the best. Peristaltic concrete pumps are the easiest to use and the least expensive to maintain.

With a 2″ squeeze pump, you can shoot sand- cement mixes with some pea gravel. A smoother finish is achieved without the pea gravel. A compressor for this pump will be in the 24 CFM to 185 CFM range depending on if you are using a plaster nozzle or a shotcrete nozzle. Plan on 3 to 7 well trained people to keep things working efficiently. This can be a nice scale for building several homes, SCIP construction like Metrock panels, small commercial work and shotcrete water tanks.

DIY Shotcrete. 8-16 YPH With ready mix, you will want 2″ hose package and a consistent 8-10 YPH capacity is a nice working pace. The Blactcrete RD3665 is my personal favorite as the best full on DIY shotcrete pump. If you are pushing for 70-100 yards per day with readymix ,this is your pump. If a pump salesman tries to sell you on a 30 YPH monster pump, ask him who is going to hold the hose, because I guaranty it won’t be one or two people. The maximum flow is about 16 YPH through a 2″ hose but it won’t be easy or likely to happen on a DIY shotcrete scale. I prefer the peristaltic pumps for all DIY size pumping jobs. If I were setting up for more than 300 yards per week consistently I would look towards an Olin 540 Ball valve pump.

For a 2″ hose, limit the maximum aggregate to ASTM size 78 of aggregate.. Although a pump salesman will try to entice you into a swing tube pump, at this scale, while you are holding the ,a smoother ball vale pump will cost less to own and operate while being nicer to use. A compressor for a 2″ shotcrete nozzle should be a minimum of 185 CFM. You will get better compaction with a 250-325 CFM compressor.

Stucco Sprayer for Walls

The Tirolessa USA Stucco Sprayer can be used for applying plaster, shotcrete, papercrete, earthen mixes, plastering a stucco house, traditional one coat or three coat stucco, GFRC, stamped concrete, stucco fences, organic sculptures, and more!

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Wall & Ceiling Stucco Sprayer

The new Wall and Ceiling Combination Sprayer has a stainless steel hopper for unmatched durability. The unique hopper angle and overflow flap allows for application on ceilings or higher areas. It can be used to spray mortar, plaster, small scale shotcrete, papercrete, earthen mixes, and more!

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3-Hole Plaster Sprayer

The Plaster Sprayer is a favorite tool of concrete artisans and plastering professionals. The stainless steel hopper is extremely durable and easy to clean. The extension handle and hopper handle are designed to give you good control, balance and comfort while you are applying material.

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DIY Shotcrete for all production rates. Whether the goal is one wheelbarrow or one readymix truck at a time, the basics are still the same:

  • Break down the complete process into steps and organize each one.
  • Look at the material flow.
  • Set up the mixing / pumping location as close to the work area as is practical. Limit the length of hose needed to make pumping easier.
  • Stage the all the sand, cement water and other material close to the mixer and organized to ease the work on the mixing crew.
  • Organize your clean up routine and supplies before pumping.

If you have specific pumping or DIY shotcrete questions, please contact Nolan and it is likely he will be able to help with the question or introduce you to someone that can.

One last note on Shotcrete pumps. Unless you are doing heavy construction or have some other very specific need, the extra surge in a swing tube pump is too big of a hassle to consider. I know the excitement of trying a new pump. It’s a BIG job to take it on, so please don’t hesitate to call and talk to me about the details before anyone convinces you that you need a swing tube pump in your life.