PreConstruct AIA framing estimate is a count of every piece of wood and hardware in the house, plus the labour to stand it up. Most framers price it as one number — labour, lumber and markup together — so the takeoff has to give you both a lumber list and the quantities your labour is priced by. This guide goes through it in the order most estimators work.
1. Read the whole set before you count anything
Walls, heights and openings come from the architectural plans, sections and elevations. Joists, beams, lintels and sheathing come from the structural or framing plans and their notes. Engineered floors and trusses come from the supplier’s layout. Framing plans often use a mark such as J1 for a callout like 11-7/8 inch TJI 230 at 16 inches on centre, listed in a legend.
In Ontario, Part 9 houses take joist, rafter and beam spans from the Ontario Building Code span tables, lintels from its lintel tables, and trusses are engineered by the truss supplier. A takeoff counts what those sizes are; it does not choose them. If a size is not on the drawings, ask the designer or engineer.
2. Walls
| Item | How it is usually counted |
|---|---|
| Studs | Wall length × 12 ÷ spacing, rounded up, plus one |
| Corners | Add 3 studs at each 90° corner (4 at a 45° corner) |
| Walls teeing in | Add 2 studs for each intersecting wall |
| Openings | 2 king studs, 2 jack studs, a header and cripples at every door and window |
| Plates | Wall length × 3 — one bottom plate and a double top plate |
| Headers | Opening width plus bearing at each end, in the plies the lintel table or engineer calls for |
| Sheathing | (Length × height − openings) ÷ 32 square feet a sheet, rounded up |
Add rough sills under windows, fire blocking where walls are tall enough to need it, anchor bolts and sill gasket along walls that sit on the foundation, and any temporary bracing. The most common wall mistake is taking the openings out of the stud count without adding the framing around them back in.
3. Floors
- Find the joist size, spacing and direction on the framing plan.
- Count joists across the floor: the width across the joists × 12 ÷ spacing, rounded up, plus one.
- Each joist’s length is its span plus bearing at both ends — buy the shortest stock length that covers it. An L-shaped floor has long joists in one part and short ones in the other.
- Add rim board around the perimeter, subfloor sheets and adhesive by the area, blocking or bridging rows, and joist hangers where joists hang off a beam.
4. Roofs
For a truss roof, the count comes from the truss supplier’s layout — trusses at their spacing along the building, plus girders and gable ends — and the supplier prices them. For a rafter roof, each rafter is half the span plus the overhang, times the slope factor: the square root of one plus (rise ÷ 12) squared. At a 6/12 pitch that factor is 1.118; at 8/12 it is 1.202. Add a ridge board, ceiling joists, and hurricane ties or truss clips at every truss or rafter.
Roof sheathing is the plan area grown by the overhang all round, times the slope factor, divided by 32 square feet a sheet, with clips per sheet. Hips and valleys are measured along their line on plan and run at 45° to the common rafters, so their true length is the plan length × √(1 + rise² ÷ 288).
5. Stairs, posts and hardware
Stairs are counted by the flight: usually three stringers, treads and risers for each. Posts are counted from the foundation and framing plans. Hardware and fasteners — nails, joist hangers, hurricane ties, connectors and anchor bolts — are the category most often left off a framing takeoff, so give them their own lines.
6. Labour
Ontario framers often price labour by the square foot of the house, and published labour-only figures for custom homes run from about $16 to more than $25 a square foot of building footprint, higher in the GTA and on complex designs with multiple roof lines, vaults, steel beams and cantilevers. Your own crew’s numbers are the ones that matter: track floor square feet, wall feet, roof squares and flights against the hours they take.
7. What gets missed
- Corner and intersection studs, and the kings, jacks and cripples at openings.
- Headers over every opening, not only the big ones.
- Fire blocking, blocking behind fixtures, and temporary bracing.
- Hangers, ties, anchors and nails.
- A span longer than the longest stock length you can buy — check where it bears.
- Revisions: take off from the latest issue and note which one you priced.
Doing this in PreConstruct AI
You draw the walls and outline the floors and roofs; your framing types turn them into the counts above, with the arithmetic on every line and labour quantities your crew rates price. It reads the framing callouts the drawings print, for you to check. It never sizes a member — sizes stay the drawings’ and the engineer’s. See how framing takeoff works.