Quick answer: A washable cardboard cave is a sturdy box shell with a removable fabric liner. Cut one clean entrance, peel off every staple and plastic tape strip, then sew or fold a remnant cushion that slips out for the wash. Inspect seams and edges weekly, trim loose threads, and recycle the box once it softens or tears.
Cardboard is cheap, warm and familiar to most cats, but it cannot go in the washing machine. The trick behind a washable cardboard cave is to separate the parts: the box is a disposable shell, while the soft lining that collects hair and dirt is made from fabric remnants you can launder and reuse in the next box.
This guide walks through choosing a box, cutting an entrance, making a liner from offcuts, and the checks that keep the cave safe over weeks of use. For more ideas on soft resting spots, see our DIY cat beds and caves hub.
Why Cats Take to a Box Cave
International Cat Care describes cardboard boxes as something that was undoubtedly invented for cats, and lists them alongside paper bags and cupboards as places cats explore and play. A cave adds a roof and a single doorway, which turns an open box into a den the cat can watch the room from.
The same charity notes that a home with plenty of places to disappear from view gives a cat more choices. A cave does not replace high resting spots, but it adds a low, enclosed option for cats that prefer to tuck themselves away when visitors arrive. Our guide on why cats hide from guests explains why that retreat matters.
A cave also works well near a radiator-free wall in a living room, where it stays out of foot traffic but in sight of the family.
Choosing the Box and the Remnants
Pick a double-wall shipping box roughly the length of your cat when stretched out and tall enough for the cat to sit up inside. Single-wall cereal or shoe boxes crush too quickly. Avoid boxes that held cleaning products, chemicals or food that leaked, and skip glossy printed boxes that shed flakes when scratched.
Before committing, leave the empty box on the floor for a day. If the cat climbs in on its own, the size is right; if it sniffs and walks away, try a box with a lower rim or a different spot in the room before cutting anything.
For the liner, use offcuts of tightly woven cotton, fleece or upholstery fabric. Tight weaves shed fewer threads than loose knits or chunky wool, and they survive repeated washing. Leftover sofa fabric or an old fleece throw cut to size both work well.
| Part | Good choice | Avoid |
|---|---|---|
| Shell | Double-wall shipping box | Waxed, printed or stained boxes |
| Liner top | Fleece or tight cotton | Loose knits, wool, fringed fabric |
| Filling | Folded towel or old fleece layers | Loose stuffing, beads, foam crumbs |
| Closure | Fold-over flap or simple seam | Buttons, ribbons, drawstrings |
Building the Washable Cardboard Cave Step by Step
- Strip the box of all plastic tape, labels and metal staples, then tape the base again with paper tape on the outside only.
- Turn the box on its side so an open end becomes the front, or close all flaps and cut a doorway in one long side.
- Draw an arched entrance about two hand-widths across and cut it with a sharp craft knife in several light passes.
- Fold the cut edge inward or cover it with a strip of paper tape so no rough card faces the cat.
- Measure the inside floor and cut two layers of fabric slightly larger, with a folded towel between them.
- Sew around three sides, slip the towel in, then fold the fourth edge over or stitch it closed.
- Drop the liner in and check that it lifts out in one piece without catching on the box.
Cutting the entrance in several shallow passes leaves a smoother edge than one hard cut. If you are using an old moving box, our guide to building a cardboard castle from moving boxes shows how to reinforce corners before cutting.
Sewing a Liner That Survives the Wash
A liner that stays in one piece through the washing machine has short, tight stitches and no loose ends inside. Backstitch at the start and end of each seam, and trim thread tails close to the knot. If you cannot sew, a fleece square folded around a towel and closed with a few hand stitches still works.
Wash the liner on its own the first time to check it does not shed fibres. Some fleece pills heavily after one cycle; if it does, swap to a smoother fabric for the top layer.
Make two liners so one can be in the wash while the other is in use. Swapping them on the same day each week keeps the cave fresh without leaving the cat without a bed.
The Safety Checklist
Most risks in a cardboard cave come from small parts and fibres rather than the card itself. VCA Animal Hospitals notes that cats are notorious for ingesting thread, wool, paper, rubber bands and small toys, and that thread or string can become dangerous once swallowed. Run through this list when you build the cave and again every week.
- No staples, metal clips or plastic packing tape anywhere on the shell
- Paper tape only on the outside, pressed flat with no tails
- Entrance edges folded or covered, with no flaps hanging loose
- Liner seams intact, with no loops, tassels or dangling threads
- No buttons, sequins, ribbons or drawstrings on the fabric
- Box placed on a flat floor, away from heaters, candles and cords
If you find chewed fabric or card inside, take the cave away and watch your cat for vomiting or a change in appetite. Contact your vet if anything seems off. Our list of tape, ink and staples to avoid in cardboard builds goes into more detail on materials.
Cleaning Routine and When to Recycle
Shake the liner outside every few days and wash it weekly with an unscented detergent. Strong fragrances can put some cats off a bed they liked before. Let the liner dry fully before returning it, since damp fabric inside a box encourages musty smells.
The shell is the part you replace. Recycle it when the walls start to soften, the entrance tears, the base bows, or the box picks up a smell after an accident. A fresh box takes a few minutes to prepare, and the clean liner moves straight across.
If your cat also uses cardboard for scratching, a separate scratcher nearby saves the cave from being shredded. Our DIY cat scratcher hub covers cardboard and sisal builds that take that job away from the bed.
Variations for Kittens, Seniors and Cold Rooms
For kittens, keep the entrance low and the box small so the cave feels snug, and check more often for chewing. Kittens explore with their mouths, so inspect the liner after every few days of play.
For older or stiff cats, cut the entrance close to the floor so there is no lip to step over, and use a thicker towel layer for cushioning. In a cold room, a second fleece layer helps; avoid heat pads inside a cardboard shell. If you want a warmer setup, our guide to a winter heated bed cover for senior cats explains safer options. For more zero-cost projects from packaging, browse zero-waste DIY toys from packaging for kittens.
Questions About Washable Cardboard Caves
Can I put the whole cardboard cave in the washing machine?
No. Cardboard breaks down when wet, so only the fabric liner should be washed. That is why the design keeps the liner removable. Wash it weekly in unscented detergent, dry it fully, and replace the box shell itself whenever it softens, tears, or picks up a smell after an accident.
What fabric remnants are safest for a cat cave liner?
Tightly woven cotton, smooth fleece and upholstery offcuts are good choices because they shed few threads and handle repeated washing. Avoid loose knits, wool, fringed edges and anything with buttons, sequins or ribbons. Trim thread tails after sewing and check the seams each week for loops a cat could catch or chew.
Is printed cardboard safe for a DIY cave?
Plain brown shipping boxes are the simplest choice. Glossy printed boxes can flake when scratched, and boxes that held chemicals or leaking food should be avoided. Remove plastic tape, labels and staples before building, and use paper tape only on the outside where the cat cannot pull it loose.
How often should I replace the box?
Replace the shell when the walls soften, the base bows, the entrance edge tears, or it holds an odour. In daily use that can be every few weeks, sooner if the cat scratches it. Because the liner moves straight into the next box, swapping the shell only takes a few minutes.
