SGUK Outdoor Skills Challenge 58: Make a Clay and Grass Plaster to Seal a Shelter Wall

A simple shelter wall can have gaps that let wind through, even when the frame itself is strong. Clay-rich soil mixed with plant fibres can form a natural plaster that fills small spaces and helps bind materials together. Your challenge is to make a small test panel and see how well your mixture works.

Your Challenge

Make a clay-and-grass plaster from natural materials and apply it to a small, temporary section of a shelter wall or a test panel made from fallen sticks.

You are testing the mixture, not building a permanent shelter. Do not plaster living trees, damage an existing shelter or interfere with someone else’s structure.

What You’ll Need

• A small amount of clay-rich soil collected where permitted
• Short pieces of naturally fallen, dry grass
• Water, if available from a suitable source
• Fallen sticks to create a small test panel

If the ground does not provide suitable clay, do not substitute random soil and expect the same result. Choose a more suitable location or complete the challenge another time.

Take the Challenge

1. Make a small frame. Arrange fallen sticks into a panel with a few narrow gaps between them. Rest it securely against the ground or another stable support.
2. Prepare the soil. Add water gradually to a small amount of clay-rich earth until it becomes a thick paste. It should hold together rather than run off the sticks.
3. Add the grass fibres. Tear or break the dry grass into short lengths and mix them through the clay. The fibres help reinforce the plaster, but too much grass can make it difficult to spread.
4. Test the consistency. Press a small amount onto one of the gaps. If it falls away, try adding a little more clay-rich soil. If it is too stiff to spread, add a few drops of water.
5. Seal the gaps. Work the mixture into the spaces between the sticks. Press it gently into place rather than simply laying a thick layer over the surface.
6. Inspect your work. Check whether the plaster stays attached and whether any gaps remain. If conditions allow, leave the panel to dry naturally and look for cracking or shrinkage.

Keep the test small. A natural plaster will not necessarily make a shelter waterproof, and heavy rain can soften or wash away an unsuitable mixture. When finished, dismantle your panel and return the materials without leaving litter or damaging the site.

Check Your Results

Check your plaster against these points:

• Does the mixture hold together when moulded?
• Are the grass fibres distributed throughout the clay?
• Has the plaster filled the gaps between the sticks?
• Does it stay in place when you gently handle the panel?
• If it has dried, are there cracks or loose sections?

Complete the Challenge

Your challenge is complete when you have made the plaster, applied it to a test panel, checked how well it seals the gaps and photographed your work.

How to Submit Your Challenge

Submit your evidence

1. Go to your SGUK member profile.
2. Open Social Activity.
3. Upload a photograph of your evidence to the activity wall.
4. Add the hashtag #SGUKChallenge58.
5. Share it for verification.

Challenge 58 Checklist

Want to Push Yourself?

Make two small test panels, using different amounts of grass in each mixture. Compare how easily the plaster spreads, how well it stays in place and whether it cracks as it dries.

What’s Next?

If you haven’t completed the previous challenge, try SGUK Outdoor Skills Challenge 57: Make a Mud Oven. You can complete the SGUK Challenges in any order.

Once you’ve shared your evidence and it has been verified, the SGUK Outdoor Skills Challenge 58 is complete and the completed challenges figure will be updated on your profile.

Learn. Practise. Master.

That’s what the SGUK Outdoor Skills Challenge is all about.