Cornish-Windsor Covered Bridge — materials

A rough list to take to a sawmill. The frame is cut green — full-sawn timbers straight from the log — and bolted with iron at its joints, as this one was built. The mill cuts every stick to its section and length; the framer cuts the joints.

Each length is the piece’s cut length plus 3 in for trimming (no tenons: the joints are notches and bolt holes), rounded up to the foot. A piece longer than 24 ft is ordered in two or more lengths joined by a scarf (A2-16). Board feet are full-sawn: width × depth × feet ÷ 12. Sizes follow the model, which is proportioned from measured drawings, not engineered — a frame that will carry a load is sized by an engineer first.

Section (in)	Length (ft)	Pieces	Board feet	For
8 × 10	24	38	6,080	tie beam
4 × 16	21	225	25,200	floor beam
5 × 10	22	4	367	primary chord, timber · secondary chord, timber
5 × 10	21	336	29,400	primary chord, timber · secondary chord, timber
5 × 10	18	8	600	secondary chord, timber · primary chord, timber
5 × 10	14	8	467	secondary chord, timber · primary chord, timber
5 × 10	13	4	217	secondary chord, timber · primary chord, timber
5 × 10	10	12	500	primary chord, timber · secondary chord, timber
6 × 8	21	436	36,624	lattice timber
6 × 8	19	8	608	lattice timber, cut at the truss end
6 × 8	13	8	416	lattice timber, cut at the truss end
6 × 8	7	8	224	lattice timber, cut at the truss end
3 × 10	22	2	110	primary chord, plank
3 × 10	21	168	8,820	primary chord, plank
3 × 10	18	4	180	primary chord, plank
3 × 10	14	4	140	primary chord, plank
3 × 10	13	2	65	primary chord, plank
3 × 10	10	6	150	primary chord, plank
4 × 6	14	112	3,136	lower lateral brace
4 × 6	7	76	1,064	knee brace
4 × 6	5	76	760	sway brace
4 × 5	24	74	2,960	upper lateral brace
1 3/4 × 10	2	896	2,613	shear block
2 × 8	16	376	8,021	rafter
2 × 8	13	38	659	collar beam

129,380 board feet of green timber in 2929 pieces.

56 members are longer than a 24 ft stick and are scarfed.

Iron: 448 bolts 7/8 in by 31 in, through the primary chords and both lattice timbers; 444 bolts 7/8 in by 22 in, through the secondary chords and both lattice timbers; 670 bolts 5/8 in by 12 in, through the two lattice timbers between chords; 3,124 cast washers. Cast washers under every head and nut; the bolts at the ties, braces and floor are not recorded and not counted.

Boards: deck about 8,848 sq ft at 4 in thick (≈35,393 board feet); roof boards about 13,726 sq ft at 1 in (≈13,726 board feet). Add for waste.

Not in this list: stone, brick and mortar; siding, trim, windows and doors; roofing; nails. Nothing here is priced.

Cut list, piece by piece

Piece	Qty	Section (in)	Cut length (in)	Ends
Lattice timber	436	6 × 8	248 1/2	level, flush under the lower chord · level, flush with the upper chord top
Lattice timber, cut at the truss end	12	6 × 8	71 7/8 – 224 5/8	level, flush under the lower chord · plumb at the truss end
Lattice timber, cut at the truss end	12	6 × 8	71 7/8 – 224 5/8	plumb at the truss end · level, flush with the upper chord top
Primary chord, timber	8	5 × 10	108 – 252	square, at the truss end · same
Primary chord, timber	178	5 × 10	108 – 240	butt joint between bolt lines · same
Primary chord, plank	8	3 × 10	108 – 252	square, at the truss end · same
Primary chord, plank	178	3 × 10	108 – 240	butt joint between bolt lines · same
Shear block	896	1 3/4 × 10	10	square · same
Secondary chord, timber	8	5 × 10	108 – 252	square, at the truss end · same
Secondary chord, timber	178	5 × 10	108 – 240	butt joint between bolt lines · same
Floor beam	225	4 × 16	246	seated on the inner lower chord · same
Lower lateral brace	56	4 × 6	297 3/8	butted to the inner lower chord, spiked under the floor beams · same; A2-04 halving at the middle
Tie beam	38	8 × 10	284 1/2	on the upper chord, flush with its outer face · same
Collar beam	38	2 × 8	152 3/4	lapped on the rafter, nailed · same
Sway brace	76	4 × 6	53 3/8	plumb against the inner secondary chord, bolted · level under the tie beam, spiked
Knee brace	76	4 × 6	74 1/2	level on the tie beam, spiked · lapped on the collar, bolted
Upper lateral brace	74	4 × 5	282 7/8	butted to the tie beam, on the upper chord · same; A2-04 halving at the middle
Rafter	376	2 × 8	183	A6-20 birdsmouth on the upper chord, 10 in tail · plumb, butted at the ridge