Apt.1 1F Japanese Room: Ceiling Repair Vol.1

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u270fufe0f Originally published: 2021-09-01 / ud83dudd04 Updated: May 2026

Hi, it’s DIY Dad! The 1st-floor 4.5-mat room ceiling renovation starts now. Just like the 2nd-floor Japanese room (u548cu5ba4 washitsu), the ceiling here is an old saodare style (u7affu7e01u5929u4e95 u2014 thin boards supported by narrow horizontal battens). The plan: paint over it.

Once the ceiling substrate is level, the first step is a sealer coat to block staining and even out absorption. I used Miracle Sealer for this.

Normal practice is to cut in the edges with a brush first, then roll the large open areas. This time, though, I’m planning to try spray painting the edges with an air compressor u2014 so I left the edges for later and just roughed in the large areas with a roller first. Since this is essentially the same process as the 2nd floor, I moved through it quickly.

2026 DIY Dad Notes: 2F Wall Underlayment and Pre-Wallpaper Prep

2026 DIY Dad Notes: 2F Wall Underlayment and Pre-Wallpaper Prep

ud83duded2 RECOMMENDED PRODUCTS

Fusuma Replacement Paper Kits

Fusuma renewal is the fastest Japanese-room refresh u2014 paper, paste, and 2 hours.

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With the wall underlayment boarding and patching progressing well, we’re entering the final prep phase before wallpaper goes up on the 2nd floor. Underlay quality determines finish quality.

Drywall (Plasterboard) Installation Tips

Vertical orientation is standard u2014 fewer seams
Fasten screws at 300 mm intervals or less
Float the board 5u201310 mm off the floor (don’t sit it on the floor directly)
Reinforce around openings u2014 windows, doors
Cut out holes for outlets and switches before hanging

Drive each screw just enough so the head sinks slightly below the board face u2014 this lets compound sit in the recess. Driving too deep splits the board face paper.

Patching Seams and Screw Holes

Apply mesh tape over all seams (crack prevention)
First compound coat: thick enough to fully embed the tape
Sand after drying
Second compound coat: thin, spread wide
Sand again after full drying u2014 flat, smooth surface

“Thin coats, multiple passes” is the rule. One thick coat cracks as it dries u2014 DIY Dad learned this the hard way on the first attempt.

Pre-Wallpaper Checklist

All compound fully dry?
Surface smooth to the touch?
No steps or warps across the wall face?
Is a sealer coat needed?
Masking ready (floor, ceiling, tategu)?

In old buildings, getting a perfectly flat wall is sometimes not realistic. “Wallpaper will hide minor irregularities” u2014 that realistic acceptance is a valid part of the DIY mindset.

Actual Material Costs: 2F Japanese Room Wall Renovation

Drywall (12.5 mm u00d7 910 u00d7 1820 mm): ~u00a52,000 u00d7 10 sheets = u00a520,000
Mesh tape: ~u00a5500
Joint compound: ~u00a51,500
Screws (32 mm): ~u00a5500
Total materials: ~u00a522,500

Add approximately u00a53,500 for wallpaper (6-mat room). A contractor would charge u00a5300,000u2013500,000 for drywall through wallpaper in a 6-mat room. DIY cost: roughly u00a526,000 in materials. The difference speaks for itself.

Starting the 1F Ceiling

With the 2nd-floor wall work on track, I’m also beginning the 1st-floor ceiling renovation in parallel. Running multiple rooms simultaneously shortens the total project timeline. The 1st-floor ceiling gets the same paint treatment as the 2nd floor, but with extra attention to finish quality since the 1st floor is what tenants see most.

Applying sealer to the ceiling and the built-in closet (oshi-ire):