Proper attachment of the deck ledger to the house is critical for ensuring that an “attached” deck is safely and securely supported at this location.  Here we provide details for attaching a 2” nominal lumber deck ledger to the side of residential floor ladder constructed with metal plate connected wood (MPCW) floor trusses.

Details for attachment of deck ledgers to the end of floor trusses can be found here.



Minimum Ledger Requirements

  • 2x10 or 2x12 lumber
  • Specific gravity > 0.43
  • Identified by the grade mark of, or certificate of inspection issued by, an approved lumber grading or inspection bureau or agency.

  • Made of PPT (Preservative Pressure Treated) or code approved decay-resistant lumber
  • Pressure treatment must be an approved process in accordance with American Wood Protection Association standards.

Step 1

Review Connection Details

  • Determine fastener spacing based on the following conditions:
    • Joist span (up to 18’)
    • Applicable loading (40 psf or 60 psf)
    • Connection type (side)
    • Fastener type (bolt or lag screw)

Vertical Load Connection Detail

Lateral Load Connection Detail – Ledger Attached at Truss End

Step 2

Install Over Structural Sheathing

  • Install ledger directly over wood structural sheathing fastened to the wall per IRC Chapter 6.
  • Maximum thickness of sheathing is 15/32".

  • Attach ledger through wood structural sheathing into one of the following:
    • 2-ply 2x4 truss end vertical
    • 4x4 vertical web
    • Key-block



  • Attach ledger with:
    • ½" x 6" lag screws or
    • ½"-diameter Standard Hex bolts with washers and nuts
    • Lag screws and bolts must meet the requirements of ANSI/ASME Standard B18.2.1

  • Maximum one fastener per truss member or key-block.
  • Install fasteners through the centerline of the truss member or key-block
  • Position fasteners to avoid interfering with bottom and top chord joints and connector plates.

Step 3

Fastener Specification

  • Lag screws and bolts must be installed according to 2015 NDS requirements.
  • A "test" installation is recommended before drilling the lead holes, to ensure that the lead holes are neither too small nor too large.

  • ½" x 6" lag screws:
    • Lead holes for the threaded portion must be 5/16". 
    • Clearance holes must be ½" and the same depth of penetration as the length of unthreaded shank.
  • ½"-diameter bolts:
    • Holes must be a minimum of 17/32" to a maximum of 9/16".



  • All fasteners used with PPT wood must be hot-dip zinc-coated such as:
    • Galvanized steel
    • Stainless steel
    • Silicon bronze
    • Copper

  • Fasteners must meet ASTM A153, Class D, for fasteners 3/8" diameter and smaller or Class C for fasteners with diameters over 3/8".
  • Lag screws, bolts, nuts and washers are permitted to be mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B695, Class 55, minimum.

Step 4

Hardware Specification

  • All hardware (e.g., joist hangers, hold-down devise, etc.) must be galvanized or stainless steel.
    • Hardware hot-dipped prior to fabrication must meet ASTM A653, G-185 coating.
    • Hardware hot-dipped post fabrication must meet ASTM A123.

  • Additional requirements include:
    • Fasteners and hardware exposed to saltwater or located within 300' of a saltwater shoreline must be stainless steel grade 304 or 316. 
    • Fasteners and hardware must be of the same corrosion-resistant material.
    • Other coated or non-ferrous fasteners or hardware must be approved by the authority having jurisdiction.

Step 5

Flashing Installation

  • Install flashing at top of ledger for water tightness.
  • Flashing must be corrosion-resistant metal of minimum nominal 0.019" thickness or an approved non-metallic material.
    • Do not use aluminum flashing in direct contact with lumber treated with preservatives containing copper, such as ACQ, Copper Azole or ACZA.

Step 6


  • Two-ply 2x4 truss end verticals, 4x4 truss vertical webs and key-blocks connected to ledger with lag screws or bolts must have a specific gravity, G ≥ 0.42 (includes DF, HF, SP and SPF).
    • Construct key-blocks with minimum 2x4 No. 2 or better lumber. 
    • Install key-blocks at required locations. Cut to fit tight.

Step 7

Connect Joist to Lateral Load Connection

  • Apply minimum 2x_ SPF block of same depth as deck joists to one side of each vertical web or key-block to which the hold-down is attached.

  • Cut block to fit tight between exterior sheathing and side of first interior floor truss
  • Carefully notch block for tight fit around top chord of ladder frame.

  • Attach block to side of web or key-block and to floor sheathing with 10d nails @ 3" o.c.

  • Apply Hold-Down capable of resisting 750 lbs minimum.
  • Install hold-downs at four (4) locations, evenly distributed along ledger with one (1) hold-down within 2’ of each end of ledger.

  • Attach hold-down to vertical truss web or key-blocks with lag screw.
  • Minimum 3-1/2" penetration into web/key-block to deck joist per manufacturer’s specifications.

  • Install lag screw through center of web or key-block so as not to damage or disturb connector plates.