403A floor, wall and roof framing practice questions.

Five free practice questions on floor, wall and roof framing: block D of the Red Seal 403A Carpenter exam, about 20 of its 100 questions. They are in the exam's format: four options, one correct answer. Answer each one before opening the explanation. No account, no email.

01The questions

1. Procedural · Constructs dimensional lumber floor framing

   Sawn-lumber joists span 4 800 mm (15 ft 9 in.) between a foundation wall and a beam. The NBC limits the spacing of bridging or blocking rows to 2.1 m (7 ft). How many rows of restraint are needed in that span?

   1. 0 rows
   2. 1 row
   3. 2 rows
   4. 3 rows
   Show the answer

   C. Correct. Two rows divide the span into three intervals of 1.6 m, each under 2.1 m. Rows are snapped square to the joists and cross-bridging or solid blocking is installed at the marks before sheathing.

   Why not the others

   A. A 4.8 m span is well over the 2.1 m interval, so restraint is required. Unrestrained deep joists can twist and the floor will feel springy.

   B. One row at mid-span leaves two intervals of 2.4 m, which exceeds the 2.1 m limit. Two rows, at thirds of the span (1.6 m), keep every interval under the limit.

   D. Three rows (1.2 m intervals) satisfy the limit but is more than required. Two rows meet the 2.1 m maximum interval.

2. Procedural · Constructs roof and ceiling framing

   Hip jack rafters are spaced 400 mm (16 in.) o.c. on a 9:12 equal-slope roof. What is the common difference in length between successive jacks?

   1. 400 mm
   2. 500 mm
   3. 450 mm
   4. 566 mm
   Show the answer

   B. Correct. At 9:12 (a 3-4-5 slope) the common rafter line length is 1.25 times its run, so 400 mm of spacing changes the jack length by 400 x 1.25 = 500 mm. Each jack is laid out from the longest one by subtracting 500 mm, with the same side cut and shortening at the hip.

   Why not the others

   A. 400 mm is the spacing in plan. Each jack is shorter by that much run, but the rafter length changes by the run times the unit line length.

   C. 450 mm would be 400 x 1.125 (a 6:12 unit length). At 9:12 the unit line length is 1.25, giving 500 mm.

   D. 566 mm is 400 x 1.414, the diagonal in plan. Jacks run parallel to the commons, so their length changes by the common rafter's unit length, not the hip's.

3. Procedural · Constructs dimensional lumber wall framing

   A framer is installing the second (cap) top plate on a long 38 x 140 mm (2 x 6) wall. Where should the joints in the cap plate fall?

   1. Over a stud, offset at least one stud space from the lower plate's joints, lapped at corners
   2. Anywhere between studs, since the cap plate is only a nailer
   3. Stopped short of each corner so the wall panels can be plumbed independently
   4. Directly over the joints in the lower plate so the two can be nailed together
   Show the answer

   A. Correct. The double top plate acts as a continuous beam and tie. Its joints must break over a stud so both ends bear, be staggered from the lower plate's joints (the NBC asks for at least one stud space), and the cap plate laps the adjoining wall at every corner and partition to tie the walls together.

   Why not the others

   B. The cap plate carries joist and truss loads between studs and ties the walls; a joint between studs leaves an unsupported end. Break joints over a stud.

   C. Corners are exactly where the cap plate must lap the adjoining wall. Stopping short leaves the corner untied.

   D. Stacked joints create a break in both plates at the same point: no tie, no beam action. Stagger the joints.

4. Procedural · Constructs decks

   The ledger for a new deck is going on a house with vinyl siding and a house wrap. In what order are the siding, flashing and ledger dealt with so the building envelope stays intact?

   1. Bolt the ledger over the siding and caulk along the top edge
   2. Remove the siding, apply membrane and Z-flashing lapped under the house wrap, then bolt the ledger and cap with flashing over its top
   3. Remove the siding, bolt the ledger, then install flashing over the house wrap and down the face of the ledger
   4. Install the ledger directly on the sheathing and rely on the deck boards to shed water away from the wall
   Show the answer

   B. Correct. The ledger must bear on solid sheathing, not siding. The self-adhered membrane and Z-flashing tuck up behind the house wrap so water running down the wall is carried out over the ledger, and a second flashing over the ledger's top edge keeps water off the joist hangers. Envelope integrity is an RSOS performance criterion for decks.

   Why not the others

   A. Caulk fails within a season, water runs behind the ledger and rots the rim. Siding also compresses and leaves the bolts loose. The ledger goes on sheathing with flashing.

   C. Flashing placed over the wrap lets water that is already behind the wrap run in behind the flashing. Flashing must lap under the house wrap above and over the ledger below.

   D. Deck boards shed water onto the ledger, not away from it. Without flashing the rim joist rots behind the ledger, which is the commonest deck failure.

5. Procedural · Installs engineered floor systems

   A beam is built from three plies of 44 x 302 mm (1 3/4 x 11 7/8 in.) LVL. Joists hang from one side only. How should the plies be fastened together?

   1. Glue the plies with construction adhesive and clamp until cured
   2. Follow the manufacturer's side-loaded pattern, which typically adds through-bolts or structural screws
   3. Nail from one face only with 82 mm (3 1/4 in.) nails at 300 mm (12 in.) o.c. in two rows
   4. Use the same pattern as a built-up 38 mm lumber beam, 89 mm nails at 450 mm o.c.
   Show the answer

   B. Correct. A beam loaded from one face must transfer that load across all plies, so manufacturers give a separate side-load fastening pattern, usually through-bolts or rated structural screws in rows, in addition to or instead of nails. Top-loaded beams can use the lighter nail-only pattern.

   Why not the others

   A. Construction adhesive is not a structural connection for beam plies and is not part of any LVL fastening schedule. The connection must be mechanical fasteners per the manufacturer.

   C. A one-sided nail pattern is the top-load schedule. It will not carry joists hanging off one face; the far plies would do no work. Use the side-load pattern with bolts or structural screws.

   D. That is the NBC pattern for sawn-lumber built-up beams loaded from the top. LVL plies, and any side-loaded beam, follow the manufacturer's schedule, which is heavier.

02Answer key

03What block D covers

This block covers the structural framing of a building. It includes I-joist and dimensional lumber floors, subfloor sheathing, built-up and LVL beams, decks, ledgers, guards and deck stairs, wall framing, lintels and openings, shear walls and SIPs, roof trusses and their bracing, and rafter layout for gable, hip and intersecting roofs.

The Red Seal Occupational Standard names this block “Performs framing”. It carries 20% of the exam, about 20 of the 100 questions, split across four tasks. The share column is each task's weight within the block, as the standard publishes it.

04What the questions turn on

Holes and notches

A hole in a sawn-lumber joist can be up to a quarter of its depth, kept 50 mm from the edges. A loadbearing stud keeps two-thirds of its depth. A cut I-joist flange needs a repair detail from the manufacturer or engineer.

Openings and point loads

Trimmer joists are doubled once the header they carry exceeds 800 mm, and the header itself is doubled past 1.2 m. Point loads from posts and lintels need squash blocks or solid blocking carried down through the floor.

Setting and bracing trusses

Ground-brace the first truss before setting the second, then add top-chord laterals and diagonals as each truss goes up. Continuous lateral bracing on webs also needs diagonals. Trusses are never cut without the truss designer's detail.

Rafter lengths from the slope

A 9:12 slope is a 3-4-5 triangle, so line length is 1.25 times the run, and hip jacks at 400 mm differ by 500 mm. Shorten each common rafter by half the ridge thickness, measured square to the plumb cut.

05The other blocks

The 403A exam has seven blocks. Each has its own page of free questions:

The 403A Carpenter practice exam page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.