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Building Construction Work (Structural Frame & Interior/Exterior Finishing)

Construction (Building) · 建設分野(建築区分) · Written by Tokutei Pass based on the official study texts; not copied verbatim.

Temporary Scaffolding, Earthwork, Foundation Work, and Demolition

When assembling external scaffolding, compact the ground, set sole boards (Shiki-ita) and base plates, connect standards with foot ties (Negarami), and install diagonal braces, wall ties, toeboards, and guardrails. During dismantling, restrict entry, dismantle from the top level down in the reverse order of assembly, and remove wall ties sequentially.

Before starting building demolition, always verify that electricity, gas, and water services are shut off, and erect scaffolding and soundproof sheets before proceeding step by step.

In earthwork, install 'earth retaining walls (Yamadome / Dodome)' to prevent trench cave-ins during excavation (Negiri), and pour a flat layer of 'blinding concrete (Sute-kon)' on the trench bottom as a base for layout marking and rebar/formwork placement.

On soft ground, use 'pile foundations (Kuigiso)' driven deep to a bearing stratum; set and secure anchor bolts accurately before pouring foundation concrete; backfill after stripping forms using clean soil in 20–30 cm layers, compacting each layer with a rammer.

Temporary Scaffolding, Earthwork, Foundation Work, and Demolition

Key points


  • Scaffolds require sole boards, base plates, foot ties, wall ties, and guardrails; dismantle from the top down in reverse order of assembly.

  • Temporary walls preventing excavation collapse are 'earth retaining (Yamadome)', and flat sub-base concrete for layout marking is 'blinding concrete (Sute-kon)'.

  • Fix anchor bolts before pouring foundation concrete, and backfill in 20–30 cm layers compacted each time with a rammer.
WordMeaning
Earth retaining wall / Shoring (Yamadome)
Blinding concrete / Lean concrete (Sute-kon)
Pile foundation (Kuigiso)

Rebar Work, Formwork, and Concrete Work

The shortest distance from the rebar surface to the outer concrete surface is 'concrete cover thickness (Kaburi atsusa)'; lateral ties around column main bars are 'hoops (Obikin)', and shear reinforcement rings around beam main bars are 'stirrups (Abarakin)'. Splices include 'lap splices (Kasane-tsugite)' tied with wire and 'gas pressure welded joints' heated with a burner and compressed axially to form a bulge.

Reinforce wall formwork with separators, form ties, and steel pipes to prevent blowouts (punk) from lateral concrete pressure, and support slab/beam soffits with 'formwork shoring (pipe supports)'. Strip column and wall side forms first, and remove soffit forms under beams and slabs only after verifying required compressive strength.

Pump 'initial lubricating mortar (Sakiokuri mortar)' before concrete pumping to prevent pipe blockages, and locate construction joints near the 'mid-span' where shear force is small. An incomplete joint caused by delayed placement between layers is a 'cold joint', and a void defect where coarse gravel collects due to poor compaction is 'honeycombing (Janka)'.

After placement, protect concrete from drying or freezing through 'curing (moist curing with water spraying or sheets)'. Manufacturing RC members in a factory and assembling them on site by crane to shorten schedules is the 'Precast Concrete (PCa) method'.

Key points


  • Column shear ties are 'hoops' and beam shear ties are 'stirrups'; strip column/wall side forms first and beam/slab bottom forms only after confirming strength.

  • Pump 'lubricating mortar' first, place construction joints near 'mid-span', and perform 'moist curing' after pouring concrete.

  • A weak seam from delayed pouring is a 'cold joint', and gravel pockets with voids from poor compaction are 'honeycombing (Janka)'.
WordMeaning
Concrete cover thickness (Kaburi atsusa)
Column hoops & Beam stirrups (Hoop-kin / Abarakin)
Cold joint
Honeycombing / Rock pocket defect (Janka)

Steel Frame Work, Timber Carpentry, Roofing, and Waterproofing

In steel erection, the tapered steel pin driven into bolt holes to align joints is a 'drift pin (Borushin)', and columns/beams are coated with 'fireproofing protection (Taika hifuku)' such as sprayed rock wool to prevent sudden strength loss during fires (above approx. 500°C).

In traditional Japanese 'post-and-beam timber construction (Jikugumi kouhou)', the bottom horizontal sill anchored to the foundation is the 'sill plate (Dodai)', diagonal bracing resisting lateral wind/earthquake loads is 'diagonal bracing (Sujikai)', sloped rafters supporting roof sheathing from ridge to eaves are 'rafters (Taruki)', and angled timber joints are 'joinery (Shikuchi)'.

Roof detailing that channels rainwater away to prevent leaks is 'weatherproofing (Amajimai)'; lay asphalt roofing underlayment from the 'lowest edge (eaves / Nokisaki) upward toward the ridge (Mune)' so upper sheets overlap lower sheets.

In adhesive sheet waterproofing, clean the substrate and firmly roll around drains, inside corners, and laps; in urethane liquid membrane waterproofing, remove puddles after rain and wait until the substrate is dry with verified moisture content to prevent blistering.

Key points


  • Align steel bolt holes with a 'drift pin (Borushin)', and apply 'fireproofing (Taika hifuku)' to prevent collapse at fire temperatures over 500°C.

  • In timber framing, the bottom sill is 'Dodai', diagonal wall bracing is 'Sujikai', roof rafters are 'Taruki', and angled joints are 'Shikuchi'.

  • Lay asphalt roofing from 'eaves (low) to ridge (high)', and apply urethane waterproofing only after the substrate is dry.
WordMeaning
Drift pin for bolt alignment (Borushin)
Fireproofing coating on steel (Taika hifuku)
Sill plate, Diagonal brace & Rafter (Dodai / Sujikai / Taruki)
Rainwater detailing / Weatherproofing (Amajimai)

Plastering, Tile/Stone, Glazing, Painting, and Interior Finishing

An outward-projecting wall corner is an 'outside corner (Dezumi)' and an inward-recessed corner is an 'inside corner (Irizumi)'. Apply plaster mortar in multiple coats (undercoat, brown coat, finish coat) to prevent sagging and shrinkage cracks, and moist-cure with sheets or water spray under direct sun or wind.

Comb tile mortar with a notched trowel, set tiles within the open time, and vibrate/tap them so mortar fills the back ribs. Repair delaminated exterior tiles without breaking them by drilling through joints, injecting epoxy resin, and pinning with stainless steel pins; fixing stone panels with metal anchors without mortar is the 'dry method (Kanshiki kouhou)'.

Suspend painting work when relative humidity is '85% or higher'. Execute sealant work in order: Clean → Masking tape → Primer → Backup rod → Fill sealant → Tool with spatula → Remove tape immediately. Place two hard-rubber 'setting blocks' in the bottom sash channel to support glass weight.

Install bagged glass-wool insulation without gaps with the vapor-barrier film facing the 'indoor side', and level ceiling furring bars (Nobuchi) before boarding. Drive gypsum board screws 0.5–1 mm below the paper surface without tearing it, cut outlet holes with a keyhole saw, sand putty smooth before hanging wallpaper, press seams with a joint roller, and allow 'open time' after spreading adhesive before laying vinyl floor sheets.

Key points


  • An inward corner is 'Irizumi', fixing stone with metal anchors is the 'dry method', and painting stops at '85% or higher humidity'.

  • Place two 'setting blocks' under glass panes, and face the moisture-barrier film of bagged insulation toward the 'indoor side'.

  • Sink gypsum board screw heads 0.5–1 mm, sand putty smooth before wallpapering, roll seams with a joint roller, and observe 'open time' for vinyl flooring adhesive.
WordMeaning
Outside corner & Inside corner (Dezumi / Irizumi)
Dry stone fixing method with metal anchors (Kanshiki kouhou)
Glass setting blocks
Adhesive open time (waiting time before laying sheets)

Building Construction (Structural and Finishing Work)

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