2. Memory Foam Mat With a Removable Cover
If your baby spends long stretches in the playpen, cushioning matters more than charm. A memory foam mat gives you a surface that absorbs the thud of a wobbly sitting-down moment without being so soft that it makes standing up harder.
Start with a firm mattress topper or a sheet of 2-inch upholstery foam, and cut it to your playpen’s dimensions with an electric knife or a serrated bread knife — both slice foam far more cleanly than scissors. Let the foam air out flat for a day or two before covering it.
For the cover, sew a simple envelope-style slipcover or a zippered cover from a stretch cotton twill or a quilted mattress protector fabric. Add a hidden zipper along one long edge so the whole thing can come off and go in the wash. A non-slip shelf liner or a few dots of silicone caulk on the underside keeps it from creeping across hardwood.
Time: One to two hours. Difficulty: Beginner to intermediate, depending on whether you add a zipper.
For a quicker version, buy a zip-on waterproof mattress cover in the closest standard size and fold or tuck the excess underneath. It won’t be tailored, but it’s a ten-minute solution that works.