⚡ Astonishing Speed
A well-organised team with a spray machine can cover triple the square metres per day compared to traditional hand-throwing.
Machine Rendering (Spray) vs Hand Rendering: Speed, Cost and Quality
The image of the plasterer expertly throwing mortar at the wall with his trowel is deeply engrained in Greek construction. But in recent years, the characteristic hum of the “press” (the spray rendering machine) is heard on more and more building sites. Whether you’re building a new apartment block or renovating a flat, the choice of application method directly affects the budget, delivery time and final quality of the project.
1. How Does Machine Rendering (Spray) Work?
The rendering machine is essentially an automated mixer and pump. The operator empties bags of factory-made render (e.g. gypsum or cement plaster) into the hopper. The machine automatically mixes the powder with the precise amount of water and pushes the slurry through a thick hose. At the nozzle end, another technician "sprays" the material evenly onto the wall using compressed air.
🎯 Perfect Consistency
The machine mixes continuously with a constant water ratio. There's zero chance of one batch being "watery" and the next "stiff," dramatically reducing the risk of shrinkage cracks.
📉 Less Waste
The material is sprayed on target and sticks immediately, unlike hand application where a fair amount of mortar falls onto the floor.
💰 Lower Labour Cost
On large projects, the machine's speed drastically reduces the total number of labour days the owner pays for.
2. Traditional Hand Rendering
It's the method everyone knows: the tradesman mixes the mortar in a mixer or bucket and throws it onto the wall by hand.
✅ Flexibility on Small Jobs
Ideal for DIYers, small bathroom refurbishments, patches or walls of just a few square metres. The tradesman unpacks his tools and starts immediately.
✅ Access Everywhere
On very narrow scaffolds, small light wells or hard-to-reach spots, the bulky spray hose won't fit. A trowel reaches everywhere.
✅ Independence
You don’t need three-phase power or machines that cost €5,000.
❌ Time-Consuming & Exhausting
It's extremely heavy manual work. On projects over 100 m², the completion time increases exponentially.
❌ The Human Factor
Mix quality and the force with which material "sticks" to the wall depend 100% on the tradesman's fatigue and experience.
3. Comparison at a Glance
| Criterion | Machine (Spray) | Hand |
|---|---|---|
| Application Speed | Extremely fast | Slow |
| Mix Consistency | Perfectly stable (industrial) | Variable (experience-based) |
| Ideal Project Size | Large renovations, new builds, ETICS | Small rooms, patches, awkward spots |
| Cost (large projects) | Lower (fewer labour days) | Higher (more labour days) |
| Material Waste | Minimal | Medium-high |
4. Useful Tips for Owners and Professionals
Because the machine sprays material under high pressure, it creates a cloud of micro-droplets around the technician. Window and floor protection must be 100% airtight, otherwise everything will be covered in mortar splatter.
⚠️ The Big Misconception: A common myth says "machine render is smoother." This is WRONG! The machine ONLY does the spraying. Levelling (screeding with a straight-edge) and final finishing (rubbing with a float) are always done by hand. If the tradesman doesn't have a "good hand," the wall will come out crooked regardless of how the material was applied.
🏭 Machine Materials
Machines don't work well with traditional "loose" mix (sand– cement–water) because the sand granules clog the rotor. The spray machine performs best with factory-made bagged renders containing special additives (plasticisers) that make the slurry "glide" through the hose.
🔌 Power & Water
Many professional spray machines require three-phase power (380V) and a continuous water supply with good pressure - something often missing on buildings under construction.
⏱️ Setup Time
The machine needs time for transport, network connection and thorough cleaning at the end. It's not worth the effort for small patches.
Related Articles
Perfect Plaster Mix Ratios: Complete DIY Mixing Guide How to Plaster a Wall (DIY): Step-by-Step Repair Guide Weather Conditions & Plastering: Heatwaves, Frost and Wind Protecting Windows, Floors & Surfaces During Plastering: Pro Tips
Application, DIY Techniques & Project Management
Return to category.
Go to categoryCentral Guide
Return to the central guide.
Go to guide