Install Floor Blocking and Bridging

A. Finished-Project Specification

Scope: one completed blocking, bridging, and reinforcement installation covering every plan-required row, bearing line, braced wall line, panel-edge location, opening, concentrated load, and cantilever on the completed floor-joist system, with a field record of blocking types, locations, fastening, manufacturer details, and inspection results.

B. Required Documentation Schedule

Document	Source	Confirmation Required
Blocking and bridging schedule	Design professional / plan set	Current revision on site
Load-transfer and opening details	Design professional / plan set	Matches installed joist layout
Engineered-joist manufacturer instructions	Manufacturer	Squash block, web stiffener, and closure-block requirements identified
Braced wall line locations	Design professional / plan set	Confirmed against floor-joist layout
Fastening schedule	Design professional / manufacturer	Fastener type, spacing, and pattern identified for blocking and bridging

C. Component Schedule

Component	Quantity	Material	Finished Size	Preparation
Solid blocking	Per plan-required rows and measured bay count	Matches joist material per approved detail	Cut to each measured bay width	Cut square, labeled by bay location
Wood or metal bridging	Per approved bridging schedule	Per approved detail or manufacturer product	Per manufacturer or plan dimension	Installed in the specified direction and sequence
Squash blocks	Per manufacturer-required concentrated-load locations	Per manufacturer instructions	Tight to specified bearing surfaces	Installed without damaging joist flanges
Web stiffeners	Per manufacturer-required bearing and hanger locations	Per manufacturer instructions	Per manufacturer dimension	Installed tight to the joist web per manufacturer detail

List every blocking, bridging, and reinforcement piece on the field record by bay or location number. Do not rely on an unlabeled piece count.

D. Fastener and Hardware Schedule

Use the fastener type, diameter or gauge, length, quantity per joint, and installation pattern stated in the approved blocking and bridging schedule for each joint type: joist-to-blocking, blocking-to-rim, bridging-to-joist, and squash-block or web-stiffener attachment. Do not substitute a generic nail or screw for a fastener the schedule specifies by product or listing.

E. Acceptance Standards

Check	Standard
Blocking-row location	Matches every bearing line, braced wall line, opening, and interval location on the approved plan
Bay fit	Each blocking piece bears fully in its measured bay without forcing joists off the recorded layout
Joist alignment after installation	Joist spacing and vertical alignment match the values recorded at the end of Project 03 within the approved tolerance
Bridging installation	Installed in the direction, sequence, and stage of loading specified by the approved detail or manufacturer instructions
Reinforcement installation	Squash blocks and web stiffeners installed per manufacturer instructions without joist-flange damage
Fastening	Matches the approved fastener type, spacing, and pattern for each joint type; no split, missed, or overdriven fasteners

F. Review, Verification, and Location Identification (Steps 1–5)

1. Review the blocking, bridging, load-transfer, opening, bearing, and engineered-joist details. Confirm the revision date of each document against the project's document-control log before using it.
2. Confirm joist spacing, alignment, and temporary stability before adding restraint. Re-check the spacing and alignment values recorded at the close of Project 03.
3. Identify every required blocking row, bearing line, braced wall line, panel edge, opening, concentrated load, and cantilever location. Mark each location on the field copy of the plan before cutting any blocking.
4. Identify manufacturer-required squash blocks, web stiffeners, closure blocks, rim-board details, and reinforcement panels. Cross-reference each location against the engineered-joist manufacturer's instructions.
5. Select blocking material compatible with the joist system and approved detail. Confirm species, grade, or engineered-product designation before cutting.

G. Measurement, Cutting, and Dry-Fit (Steps 6–8)

1. Measure actual joist-bay widths rather than assuming all bays are equal. Record each bay's measured width on the field record by its location number.
2. Cut solid blocking square and label it by location. Cut each piece to its own recorded bay measurement, not to a single nominal dimension.
3. Dry-fit blocking so it bears fully without forcing joists out of layout. Re-check joist spacing at each bay immediately after dry-fitting the blocking for that bay.

H. Blocking, Bridging, and Reinforcement Installation (Steps 9–16)

1. Install the first blocking row while maintaining joist spacing and vertical alignment. Fasten from a reference joist and verify spacing before moving to the next bay.
2. Stagger blocking only when the approved fastening method and plan permit it. Confirm the approved method before offsetting blocking pieces for face-nailing access.
3. Install additional rows at bearing lines, braced wall lines, openings, and specified intervals. Complete each row across its full length before beginning the next row.
4. Install metal or wood bridging in the required direction and sequence. Follow the manufacturer or plan-specified diagonal orientation and installation order.
5. Tension or fasten bridging only after the joists are aligned and at the required stage of loading. Confirm joist alignment immediately before tensioning or final-fastening any bridging run.
6. Install squash blocks or web stiffeners tight to the specified bearing surfaces without damaging engineered-joist flanges. Verify full contact with the bearing surface before fastening.
7. Reinforce joist bays at concentrated loads, partitions, plumbing openings, stair openings, or equipment locations only according to approved details. Do not improvise reinforcement at a location the plan does not identify.
8. Complete required rim-board and end-restraint connections. Confirm every rim-board joint and end-restraint fastener specified by the approved detail is installed.

I. Inspection and Correction (Steps 17–21)

1. Inspect every block and bridge for contact, orientation, fastening, splitting, and interference with utilities. Record the inspection result for each row or location on the field record.
2. Verify that blocking has not moved joists off layout or created high points. Re-measure joist spacing and sight the joist tops with a string line or straightedge.
3. Perform the approved floor-alignment and stiffness inspection without calling it a structural load test. Follow the inspection method stated in the approved detail; do not apply or describe a hand-pressure check as a load test.
4. Correct loose, undersized, misaligned, or damaged blocking using the approved method. Remove and replace, rather than shim or force, any piece that fails the acceptance standards in Section E.
5. Record blocking types, locations, fastening, manufacturer details, and corrections. Enter every item from Sections F through I on the field record before proceeding to Project 05.