The Benefits of Using a Commercial Plaster Sprayer

Written by Andrew Morrison

Most of us don’t have a commercial plaster sprayer machine lying around, so we can’t just run out to the garage and turn it on. That said, the benefits of using a commercial plaster sprayer are well worth investigating the availability of one in your area either to rent or to hire out (the entire job). If you have access to a commercial sprayer, it’s an incredible machine that will speed your process up dramatically. You have seen me post in the past about sprayers that we as consumers can use with great effectivity. I am still a big fan of these sprayers and highly recommend them; however, the commercial sprayer shown here, and others like it, is a big step up in power and production.

These machines have the mortar mixer built right in so you can literally mix the material and dump it straight into the pumper. The pump then drives the material down the hose and provides a constant stream of plaster. Because we have to mix the scratch and brown coats of natural hydraulic lime plaster for a minimum of 20 minutes, it’s best to have a secondary mixer on site as well so that you can work between the two to keep the flow going.

I have included some video footage of the sprayer in action on the Flathead Lake, Montana straw bale workshop from this past year. Rather than tell you about the benefits, I figured I would just show you. If you have ever plastered, you will see the advantage right away. If you have never plastered, let me tell you that the main advantage is the speed and ease of application. It still takes several people to do the work, but less than a hand applied crew.

The first video is of the scratch coat application on the interior of an exposed timber frame. The ability to quickly “cut in” around the timbers and ceiling line is immediately apparent.

The second video shows plastering on the tall gable ends. If nothing else, not having to transport the mud to the top of the scaffolding makes this machine well worth having on site. Keep in mind that even with the other sprayer I use, one would still have to transport the mud to the point of application.

The final video is of the finish coat application. Note that there are two trowel finishers in addition to the two men running the sprayer. It is also necessary to have someone making the mud. That means you are looking at at least 5 people for the crew. That’s better than the 15 people I used to have on my plaster crew that did everything by hand application.

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20 Responses

  1. I hope to be building next year in Wales. How far into the straw does the plaster penetrate?

    Is it possible to spray lime render with similar equipment?

  2. Hey Andrew,
    Do you have a photo of what the actual sprayer/mixer looks like? I didn’t see it in any of the videos. I think this is the way I want to go for the final coat in spring!!
    Thank you!

  3. Hi Keith. The penetration into the straw is great. Just how deep depends on the tightness of the bales and how close you hold the nozzle of the sprayer. Keep in mind that all plaster needs to be back troweled, so you can get extra penetration during that process. Lime is easily sprayed. In fact, that is what the video depicts: Natural Hydraulic Lime Plaster.


  4. Andrew,
    Its good to see one in action on a “real” straw bale site. I have seen them applying plasters to concrete walls.
    What kind of overall time saving does it appear to produce (in % perhaps)?. There are obviously some things that still can’t be changed, such as the curing times of coats (which are mix and weather dependent), but it certainly applies plaster much faster than I can!

  5. Looks like the hose is from American Spray Tech. I use their portable Kodiak for American Clay application. It is modified to move American Clay plaster though it does not want to move the thick stuff (Enjarre) very well, and won’t move it at all without a wetting agent. Benron has a portable pump I am told works much better. Of course, the hose from the video must be attached to a trailer pump as the portable pumps just don’t have the power to fly. Actually, the compressor is as much of a limit as the pump is. But it sure helps with ceilings. To think about hawking what I have sprayed makes me hurt even more than I already do.

  6. Thanks Kevin.

    For those folks who have specific questions about the sprayer, please feel free to write to Kevin Collom (the owner of the machine) at [email protected]. Even better, ask him your question here so we can all learn the answer…

  7. No sure about a percentage of speed increase, but I can say it is a lot faster, especially when there is a lot of cutting in to do around the frame, windows, and doors. Maybe Kevin can answer that one.

  8. Hi Andrew. That’s amazing! I have my home all plastered using hydraulic lime. It took 3 of us many weeks, but it was fun that way too. Glad to see you are still going strong and sharing your valuable knowledge.

  9. Hi Andrew, I remember that in the past you said you did a test with part of a workshop using a sprayer and part using hand tools and the sprayer was not any quicker overall. What makes this one better? What should we be looking for in a sprayer that is faster compared to one that isn’t (assuming we have the luxury of finding one at all)? Are there ones that should be avoided altogether?

  10. I would like to suggest that you attach Pinterest, Facebook, & possibly Twitter forwarding icons to your page, I often come across information in your articles which I would like to share with others or retain for my own files and the ability to forward the information to the abovementioned sites would not only be invaluable to me but it would also further your business prospects.

  11. This is a commercial sprayer which is much more powerful and able to push much more mud in a short period of time than the typical sprayers used by homeowners. The difference is the capacity and ability to self pump as opposed to a sprayer that is hand filled from a wheel barrow (for example). Both are good, but the commercial sprayer is incredibly faster.

  12. We (4 guys)sprayed cement on a 3 car garage with a porch overhang inside and out in one day. It took about 4 more days (one guy) to do the detail work around windows and doors since the spray method isn’t the best for that. It does a phenomenal job covering the large flat areas though! We put in 4 stained glass windows to make one sweet garage. The garage is load-bearing, but the house is insulated with strawbales and built around a frame to support the two floors.
    The garage was a nice compliment to the existing 2 story strawbale home.
    If you want to see photos, you can go here…

  13. Thanks for sharing. It’s interesting and useful. Actually, I’m working for a machinery company which manufactures mortar spraying machine. And many customers need it indeed.

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