All Activities
Build a battle fortress

Build a battle fortress
Green highlight

Build a cardboard battle fortress using boxes, tape, pillows, and craft materials; design walls, a gate, and test defenses safely with supervision.

Orange shooting star
Download Guide
Collect Badge
Background blob
Challenge Image
Table of contents

Step-by-step guide to build a cardboard battle fortress

Here at SafeTube, we're on a mission to create a safer and more delightful internet. 😊

Minecraft: Build an Easy Medieval Castle Tutorial [Step by Step]

What you need
Adult supervision required, cardboard boxes, colouring materials like markers or crayons, decorations like stickers ribbon or fabric scraps, glue or craft glue, pillows or blankets, scissors, tape (packing or duct)

Step 1

Pick a flat safe spot in your home to build your fortress and clear the floor there.

Step 2

Gather all your materials and bring them to your build spot.

Step 3

Draw a simple plan on a piece of paper showing where the walls gate and tower will go.

Step 4

Place the largest boxes on the floor to form the base shape of your fortress.

Step 5

With an adult's help cut a gate flap and a few windows in one box for your entrance and peeks.

Step 6

Tape boxes together at the seams to make sturdy walls.

Step 7

Stuff pillows or blankets behind wall boxes to reinforce them and add cushion.

Step 8

Make a drawbridge or gate by taping a flat piece of cardboard at one edge to the entrance.

Step 9

Build a lookout tower by stacking a smaller box on a corner and taping it securely to the wall.

Step 10

Decorate your fortress walls and tower using colouring materials glue and decorations.

Step 11

With an adult nearby gently test your defenses by tossing a soft object at the wall from a short distance.

Step 12

Reinforce any weak spots you found during the test with extra tape or pillows.

Step 13

Tidy up leftover scraps and make sure the play area is safe and comfortable.

Step 14

Take photos of your finished battle fortress and share your creation on DIY.org

Final steps

You're almost there! Complete all the steps, bring your creation to life, post it, and conquer the challenge!

Complete & Share
Challenge badge placeholder

Help!?

If I can't find large boxes, tape, or cardboard, what can I use instead?

If you don't have large boxes, use couch cushions or stack smaller boxes for the base, and if you lack tape or a flat cardboard for the drawbridge, fasten seams with string and clothespins and use a stiff book or baking tray as the bridge while decorating with markers or stickers instead of colouring supplies.

What should I do if a wall or the lookout tower keeps collapsing during the test toss?

If walls or the taped lookout tower wobble during the soft-object test, have an adult add extra tape at the seams, stuff pillows or blankets behind the wall boxes for support, and retape the tower base securely to the wall.

How can I change the activity for younger or older kids?

For younger kids, skip cutting and have an adult make pre-cut windows and low pillow-and-blanket walls and use stickers for decorating, while older kids can draw a detailed plan, safely cut the gate and windows with supervision, build a taller taped tower, and test and reinforce weak spots themselves.

How can we personalize or extend the battle fortress after it's built?

Personalize and extend your fortress by adding string-lights and a paper flag to the taped lookout tower, cutting secret tunnels between boxes, making a pulley-style drawbridge from the flat cardboard and string, and then take photos of the finished battle fortress to share on DIY.org.

Watch videos on how to build a cardboard battle fortress

Here at SafeTube, we're on a mission to create a safer and more delightful internet. 😊

I built a WW2 SUPER FORTRESS Defense in NEW Base Building Simulator! - Gates of Hell: New Update

4 Videos

Facts about cardboard crafts and fort building

✂️ DIY building teaches real engineering skills: planning, measuring, cutting, taping, and testing to solve problems safely.

📦 Cardboard is made of layered paper (often corrugated) and gets much stronger when folded or stacked—perfect for fortress walls!

🎨 Decorating with flags, shields, and craft details turns a simple cardboard structure into a unique storytelling castle.

🏰 Fortifications like castles used gates, battlements, and drawbridges—great ideas to borrow when designing your fortress defenses.

🛋️ Pillow and blanket forts are a long-loved play tradition—kids and families have been building cozy forts for generations.

How do I build a cardboard battle fortress step-by-step?

To build a cardboard battle fortress, start by planning a simple layout with walls, a gate, and a lookout. Measure and cut box openings (an adult should handle sharp tools), then tape boxes together along seams with strong packing or duct tape. Reinforce walls with overlapping cardboard and extra tape. Use pillows and blankets for a soft interior, decorate with markers or craft foam, and set play rules. Supervise children while they test defenses gently to avoid tipping or falls.

What materials do I need to build a cardboard battle fortress?

You’ll need cardboard boxes in various sizes, strong packing or duct tape, scissors and a box cutter (for adult use), marker pens, paint, glue, and craft paper or foam for decoration. Pillows, blankets, and cushions create safe flooring and barriers. Optional supplies: clothespins to hold flaps, string for flags, lightweight props (foam swords), and small clips. Keep a tidy workspace and always supervise when using cutting tools or adhesives.

What ages is a cardboard battle fortress activity suitable for?

This activity suits roughly ages 3 to 12. Toddlers (3–5) can help decorate and move soft pieces but need close adult help for cutting and heavy lifting. Children 6–9 can design, tape, and test simple defenses with supervision. Preteens (10–12+) can plan more complex layouts and lead group builds. Adjust the tasks and tools to the child’s abilities, keep supervision consistent, and focus on safe play rules to prevent accidents.

How can I keep building and testing a cardboard fortress safe?

Safety first: always supervise, keep sharp tools and hot glue for adults, and ensure walls are stable with clear exits. Build on the floor, pad hard edges with tape or cloth, and don’t stack boxes so high they might collapse. Set testing rules—no jumping on the structure and no throwing heavy objects. Inspect for loose tape, staples, or sharp edges before play. For variety, turn the fortress into a castle, spaceship, or obstacle course while maintaining the same safety habits.
DIY Yeti Character
Join Frame
Flying Text Box

One subscription, many ways to play and learn.

Try for free

Only $6.99 after trial. No credit card required

To create a safe space for kid creators worldwide!

Discovery Tools

DIY Wiki

DIY TV

Creativity Tools

How to draw

Teacher Tools

SafeTube

DIY Blog

2025, URSOR LIMITED. All rights reserved. DIY is in no way affiliated with Minecraft™, Mojang, Microsoft, Roblox™ or YouTube. LEGO® is a trademark of the LEGO® Group which does not sponsor, endorse or authorize this website or event. Made with love in San Francisco.