Apt.1 2F Japanese Room: 2nd Ceiling Repair Vol.5

u2192 Back to all English articles

u270fufe0f Originally published: 2021-08-15 / ud83dudd04 Rewritten: May 8, 2026

2026 DIY Dad’s Update: Partial Removal to Finish Coat u2014 6-Mat Japanese Room Ceiling

After finishing the 4.5-mat room’s ceiling, it was time for the 6-mat Japanese room (tatami room). This one required partial removal in some areas, making it a more involved job.

When Partial Ceiling Removal Becomes Necessary

In older apartments, partial removal is needed when:

• Water damage has caused rot or staining from roof or plumbing leaks
• Stains or mold have soaked deep into the boards
• Boards are warped or cracked, creating significant height differences
• Plaster-based material (fiber wall, gypsum) has crumbled

After removing the damaged section, a patch board (called a fusagi-ita) is installed before painting. Getting that patch board flush with the surrounding ceiling boards is the key to a clean final look.

How to Install a Patch Board

Steps for covering a removed area with new board:

• Measure the opening left by the removed boards precisely
• Choose board material that matches the thickness of the existing ceiling (4u20136mm plywood or ceiling board)
• Cut the patch slightly larger than the opening
• Screw into the existing ceiling joists (furring strips)
• Fill the seams with compound and sand flat
• Apply sealer, let dry, then paint

Careful compound work at the seams makes them nearly invisible once painted.

Why Sealer Treatment Matters

Sealer (primer/undercoat) is especially important for ceiling painting. Reasons:

• Prevents old wood from absorbing too much paint, which causes uneven coverage
• Seals in sap (resin) bleeding from the wood
• Stops existing stains and discoloration from bleeding through the topcoat (stain-blocking sealer)
• Improves paint adhesion

A sealer with sap-blocking and stain-blocking properties is particularly effective. Available at any home improvement store.

Tips for a Beautiful Finish Coat (Ceilings)

How to get a clean finish when painting a ceiling:

• Use a brush to carefully paint the edges (wall borders) first, then fill the center with a roller
• Move the roller in a “W” pattern for even coverage
• Let the first coat dry completely before applying the second (two coats is standard)
• Watch out for paint spatter when using a roller

Because you can’t look down at a ceiling, confirming the result is tricky. Holding a light source at an angle while looking across the surface makes it much easier to spot uneven coverage.

For Anyone Considering Apartment Investment and Renovation

Cost-effectiveness is everything in apartment renovation. DIY Dad keeps costs dramatically low by doing the work himself.

Marutoku Shop u2014 Renovation Materials & Lumber (Online) u00bb

Back to the Job Site u2014 First Finish Coat

Hi there, DIY Dad here! On to the ceiling u2014 finish coat time. Last time I completed the sealer treatment. There were some gaps and unevenness that bothered me, but I decided to push forward rather than dwell on it. I applied the finish coat right over the top using Eco Flat 60.

u2192 Eco Flat 60

For painting tools and materials, see DIY Dad’s Tool & Material Guide Vol.4 u2014 Paint Application.

I applied the white topcoat, expecting the paint to smooth things out somewhat u2014 but the film was too thin. It hid absolutely nothing.

u2192 Surface unevenness visible after finish coat

u2192 Surface unevenness visible after finish coat

The bumps around the patch boards are very noticeable u2014 it’s clear that paint alone won’t fill them. This needs a redo. It’s extra work, but next time I’ll apply compound to flatten the surface between the patch boards and the original ceiling.

That’s all for today u2014 see you next time!

同じカテゴリの記事を読む

8棟自主管理の経験から書いた関連記事 — まとめて読むと理解が深まります

▸ English

Tools & Materials Vol.3b: Wall Base Prep u2014 Fiber Plaster

▸ DIY Repairs

How to Fix Damaged Fusuma (Japanese Sliding Doors)

▸ Bathroom DIY

Bathroom Renovation Vol.1: Project Overview

▸ English

Winterizing Your Wood Deck to Prevent Damage

▸ English

Apt.1 Toilet Vol.2: Entrance, Wall & Floor Base

▸ English

Living Room Renovation Vol.20: Complete!