ud83dudcda Bathroom Renovation Series u2014 14 of 25
u2190 Bathroom Renovation Vol.13: Under-Floor Storage Pt.2 u00b7 Series Index u00b7 Bathroom Renovation Vol.15: Wall Base Preparation u2192
u270fufe0f Originally published: 2016-12-06 / ud83dudd04 Updated: May 8, 2026
2026 Update from DIY Dad: Under-Floor Storage & Ceiling Work in the Bathroom/Laundry Room
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Re-caulk every 3u20135 years. Black mold on caulk is the #1 tenant complaint in Japan.
The renovation is now in the second half. Under-floor storage and ceiling access hatch installation may seem like thankless work, but they’re critically important. More than ten years on as a landlord, DIY Dad is still glad these were done.
Why Install Under-Floor Storage?
Without under-floor access, the only option when floor inspection is needed is to pull up the flooring. In wet areas especially, the speed of response to plumbing problems is completely different when you have a hatch.
Benefits DIY Dad Has Experienced
- Annual visual inspection of pipes (early detection of termites and corrosion)
- Direct visual check of drain pipe joints (early leak detection)
- Ability to inspect the condition of moisture-barrier sheeting
- Doubles as usable storage space (preserved food, emergency supplies, etc.)
Under-Floor Storage Installation u2014 Step by Step
- Decide on placement (confirm it fits between existing floor joists).
- Cut the plywood and cushion floor to the opening size.
- Partially cut the floor joists and add reinforcement pieces.
- Drop the unit body in and secure it.
- Finish the lid by applying cushion floor material to it.
The critical step is reinforcing where the joists are cut. Cutting a joist reduces floor rigidity, so support pieces must be added at each cut end and screwed in. Skip this and the floor will flex.
ud83dudebf For Anyone Considering a Wet-Area Renovation
Vanity replacement is doable as DIY, but confirm drain pipe types and measurements before starting to avoid leaks.
Under-Floor Storage u2014 Making the Lid
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Hi, this is DIY Dad! Continuing the first-floor bathroom/laundry room renovation series.
The storage box itself is in place. Now it’s time to make the lid. The lid is made by fitting the cut-out section of floor board into the lid frame.
u2191 The floor board immediately after cutting.
The floor board is trimmed to fit the lid frame perfectly. For alignment purposes, the piece is first covered with protective tape and the center is marked out to match the cushion floor pattern exactly.
u2191 Layout markings on the protected piece.
All four sides are cut along the marked lines and the board is fitted into the lid frame. The lid is complete.
u2191 The finished lid.
The lid is placed onto the under-floor storage unit. Done!
u2191 The completed under-floor storage unit.
The pattern on the lid lines up perfectly with the surrounding cushion floor u2014 a great result! Pricing and specs for the storage unit are in the DIY Dad Equipment Guide u2014 Bathroom/Laundry Room Edition. Check that out too! That’s all for today u2014 see you next time!
ud83dudcda Bathroom Renovation Series u2014 14 of 25
u2190 Bathroom Renovation Vol.13: Under-Floor Storage Pt.2 u00b7 Series Index u00b7 Bathroom Renovation Vol.15: Wall Base Preparation u2192
DIY Renovation Quote Review Manual
How to read, compare, and negotiate contractor quotes. This manual saved me u00a5800,000 on a single renovation project.
ud83cudfe0 More from DIY Father
15 years of landlord experience u00b7 3 apartment buildings u00b7 DIY renovations that saved millions of yen. Browse all articles at diytosan.com
