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YOU CAN TURN EMPTY CANS INTO A ROOF

498 drink cans became a 7 square metre roof that survived two years of Hong Kong typhoons.

by Kevin Cheung / Project Kamp

FULL CAD BOM FIRMWARE DOCS

WorkshopGarden

Built with3D printing

difficulty
●●●○○
time
a week
license
license not specified
repo
repo ACTIVE0 stars

WHAT YOU’LL NEED

Videos
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COMPAREE VERDICT

This is a proper long-form upcycling project — you collect hundreds of cans, slice them open with a hand tool, fold each one into a shingle, then layer them like scales on a roof frame. Kevin Cheung built it at Project Kamp in Hong Kong and the result survived 2 years of typhoons, heavy rain and falling trees with no leaks and zero maintenance. The colours faded (red went greyish fastest) but the structure held. The hard part is not the technique — it is the collection. You need 498 cans for a 7 square metre roof, about 69 per square metre, and they must be the right diameter or the templates will not fit. The Can Slicer makes the cutting faster (under 30 seconds per can once you have the rhythm) but you still have to flatten, trim and fold each sheet by hand. Building the actual roof took 5 days. The files are free to download but the licence is not stated, so you are on your own if you want to sell the tiles or the tool. This is for someone who has the patience to collect a lot of cans, likes working with hand tools, and wants a weatherproof roof that looks like a gradient of faded logos. The one thing most likely to go wrong is running out of patience halfway through the collection phase and ending up with 200 cans in a bin.

GOOD TO KNOW

  • —Tile cut templates and Can Slicer 3D files are on the Project Kamp research page.
  • —Licence not stated on any of the downloads.
  • —No parts list — the Can Slicer uses recycled HDPE, a rolling blade from a filed-down M3 spacer, or a utility blade in Jakub Hajko's Printables variant (CC BY-NC-SA).
  • —The research page is a photo journal with build notes, not step-by-step instructions.
  • —You need 500 ml and 330 ml slim cans; other sizes will not fit the templates.
  • —Collecting 498 cans took the team more than a month.

Parts to buy

3 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • M3x10mm spacer or utility bladesFind
  • Hand drillFind
  • Metal fileFind

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Can I build this?

PrintCan Slicer body (recycled HDPE original, or 3D print STL from Printables utility-blade version)
Buy500 ml and 330 ml slim aluminium cans (498 for 7 m²), M3x10mm spacer or utility blades, hand drill, metal file
Tools3D printer or access to Precious Plastic machines, drill, file, scissors or tin snips, folding jig (optional)
SkillsHand tool work, repetitive careful cutting, measuring and folding thin metal — no welding or special metalwork training
TimeMore than a month collecting cans, a weekend making the slicer and prototyping, 5 days building the roof once all shingles are ready
Cost$ — cans are free if you collect them, tool materials under $20, main cost is your time
SafetySharp aluminium edges after cutting. Wear gloves. No mains voltage, no batteries, no chemical hazards.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

#94 How we transformed 498 aluminium cans into a roof

Project Kamp, 11 Sep 2023, about 2.6 million views — full build documentation

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the research page (Photo journal with build notes, tile templates and Can Slicer files)
  2. 2.Decide on the slicer version(Recycled HDPE original (needs Precious Plastic access) or Printables utility-blade variant)
  3. 3.Start collecting cans(500 ml and 330 ml slim only — measure before you commit, other sizes will not fit the templates)
  4. 4.Prototype the first few shingles(Test the cutting, flattening and folding before you process all 498)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Wrong can diameter. The templates are sized for 500 ml and 330 ml slim cans. Measure yours before you collect hundreds — if they are a different size the shingles will not interlock.
  • Underestimating collection time. 498 cans took the Kamp team more than a month. If you are collecting alone, double that.
  • Blade setup on the utility-blade version. The blade must protrude less than 1 mm and only touch the surface lightly — pressing it in will not work and will wreck the blade.
  • No licence stated. The downloads have no licence attached. If you want to sell the tiles or the tool commercially, you are guessing.
  • Expecting it to stay bright. The colours fade, red fastest. After 2 years the Coca-Cola and Lipton cans were greyish. Plan for a weathered look.
  • Hand fatigue. Cutting, flattening and folding 498 cans is repetitive. Break it into sessions or you will hate the project by can 150.

Does it actually keep water out?

Yes. After 1.5 years there was no leakage and zero maintenance. After 2 years it had survived Hong Kong typhoons and intense rain, though some shingles were damaged by falling trees.

What if I cannot source a rolling blade?

Jakub Hajko made a utility-blade version of the Can Slicer on Printables (CC BY-NC-SA). The utility blade works but wears faster — you cut by dragging it lightly along the surface, not pressing in, and you have to change blades regularly.

Can I use any cans?

No. The tile templates are sized for 500 ml and 330 ml slim cans. Other diameters will not fit and the shingles will not interlock properly.

How much does a square metre cost?

About 69 cans per square metre. If you collect them yourself the material cost is near zero — you are paying in time. The Can Slicer materials are under $20.

Will the colours stay?

No. UV fades them, red fastest. After 2 years the Coca-Cola and Lipton cans on the Kamp roof were greyish.

Can I sell the tiles or the tool?

The downloads have no licence attached. The Printables utility-blade variant is CC BY-NC-SA (non-commercial). If you want to sell, you are in unclear territory.

Community builds

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Discussion1

FROM THE COMPAREE TEAM

69 cans per square metre, 498 in total, and the whole thing held up through 2 years of Hong Kong weather with zero maintenance. How big would you go?

CompareeTEAM2d ago

Practical notes from our verification: the tile templates and Can Slicer files are on the Project Kamp research page but there is no stated licence on any of them, so commercial use is unclear. The Printables utility-blade variant by Jakub Hajko is CC BY-NC-SA. The research page is a detailed photo journal, not step-by-step instructions — you will be figuring out your own workflow. The single biggest variable is the cans: 500 ml and 330 ml slim only, and collecting 498 of them took the team more than a month. If you start this project, commit to the collection phase first or you will end up with a half-finished pile of metal.

Kevin Cheung / Project Kamp

Kevin Cheung designed the Can Slicer and built the roof at Project Kamp in Hong Kong with Dave Hakkens and the Kamp team. The slicer was made from locally recycled HDPE using Precious Plastic machines at Fablab Tokwawan. The project tested whether drink cans could become a real weatherproof roof — after 2 years the answer is yes.

Web

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