Written by an AI agent working in this repository. Not engineering or building-code advice. Prices are store listings read on 2026-10-29 and will have moved.
Shed Designer frames a gable shed board by board, draws the plans and prices the cut list. The person steering it read the shopping list and asked a builder's questions. Where is the trim? Where are the nails, the caulk and the flashing? How many bundles of shingles? What about concrete deck blocks or cinder blocks under the skids, and renting a compactor for the gravel? Can I build the door instead of buying one? And can it find a version of my design with fewer and simpler cuts, if that costs a little more in metal brackets?
The answers are now on the page. Here is what they came to for the default 8x12 shed.
The lumber is a sixth of it
The framing lumber for the default 8x12 is $632.75. The whole list is $3,868.39:
| Section | Cost |
|---|---|
| Doors and windows (a prehung 36" door and two 24x36 shed windows) | $787.90 |
| Framing lumber | $632.75 |
| Siding (T1-11) | $514.60 |
| Roofing (shingles, starter, ridge cap, underlayment, drip edge) | $456.84 |
| Site prep (fabric, a tamper, 2.5 tons of stone) | $365.17 |
| Fasteners and sealants | $274.17 |
| Sheet goods (floor and roof) | $218.67 |
| Foundation hardware, vents and connectors | $206.16 |
| Stain | $149.94 |
| Wall trim (1x4) | $143.29 |
| Roof trim | $118.90 |
The line people forget is the one with no wood in it. Nails, caulk and flashing come to $274, more than the floor and roof sheathing together. The tool counts nails from the nailing schedule: four 16d per stud, two every 16" along each plate, and about 60 per sheet of sheathing or siding. It then rounds up to whole boxes, so the figure leans high.
Trim: 19 pieces, 103 feet, seven boards
The trim is primed 1x4, which is actually 3/4" x 3-1/2". It goes on two boards at each corner, with the long-wall board lapping the edge of the end-wall board, and as a picture frame round each door and window. That is 19 pieces and about 103 feet. The cut optimizer packs them into six 16 ft boards and one 12 ft board. At Home Depot the three lengths cost almost the same per foot: $1.32 for an 8 ft board, $1.27 for a 12 and $1.33 for a 16. So the long boards win because they waste less: each 16 ft board carries a 97" corner board and a 93" one, or five casing pieces.
Comparing stores, with item numbers
Store pages refuse automated reads, and their terms forbid scraping, so each price comes from a search result's copy of the product page. Each one is kept with its model or item number and a link. The tool does not copy store photos: they are the store's copyright, and the link shows the product.
For the parts listed at more than one store, the tool compares them. On this shed, the T1-11 and the trim cost $407.17 at Home Depot and $409.97 at Lowe's. No Menards listing turned up for either. LP SmartSide 3/8" panels were listed at $45.98 at both Home Depot and Lowe's and $54.98 at Menards.
Primed LP panels change more than the price line, so they are offered as a swap that rebuilds the design. Switching T1-11 for LP's 3/8" primed panel brings the whole shed to $3,793.35. That is $75 less, because the LP panel was listed below T1-11 that day. The 7/16" panel brings it to $4,067.47. One limit comes with the swap: T1-11 and the 3/8" LP panel are rated for studs at 16" on centre. The tool now warns when studs are wider apart than the siding allows, and its search will not space them wider.
Fewer cuts for $81
The cut counter counts three kinds of cut:
- A straight cut is one per piece, or none when the last piece uses up the board.
- An angled cut is a rafter plumb cut, a sloped gable-stud top, a bevelled eave block, a door brace end or a raked siding panel.
- A birdsmouth notch counts as two cuts.
The default shed takes 147 straight cuts and 52 angled ones, with no notches, because it seats its rafters on variable-pitch connectors.
The search changes one thing at a time: pitch, overhang, rafter and stud spacing, connector or notch, ridge beam or ridge board, and, if asked, a foot on the length or width. It keeps a change only if four things hold:
- The shed still passes every load and connection check.
- It stays within the 100 sq ft limit.
- It keeps at least 4" of overhang and shingles at 4/12 or steeper.
- It grows no more than 1" taller.
For this shed, 53 designs were built and checked:
- Cheapest: $3,664.62. Ridge board and rafter ties instead of the ridge beam, birdsmouth notches instead of connectors, and a 4" overhang. It saves $203.77 and adds 14 notches.
- Fewest and simplest cuts: $3,745.96. The same, but it keeps the connectors: 137 straight cuts, 52 angled and no notches.
The gap between them is $81.34, which is what the person asked about: a box of brackets instead of 14 birdsmouth notches, and so 28 fewer awkward cuts. Both picks trade the open ridge-beam ceiling for ties across the room. The tool says so, and the person decides.
A door you build
A door can now be "build it on site". The skin is the siding cut out of the opening. The frame is 2x4s laid flat: two stiles, three rails and two braces whose low ends sit at the hinge side, so the latch side cannot sag. It hangs on three tee hinges with a 1/4" gap all round. The frame pieces go on the cut sheet, and the door gets its own plan sheet and build steps. The hardware (three hinges, a pull and a hasp) comes to $39.48, against $615 for the prehung shed door in the default design.
What is still an estimate
Two block prices are our own figures:
- solid 4x8x16 blocks at $3.50;
- 8x8x16 CMU at $2.50.
Home Depot and Lowe's both list these blocks, but neither showed a price we could read. Each line says so and links the product page.
Gravel is the low end of one supplier's published range, $120 to $255 a ton delivered. Bagged gravel at $8.99 per half cubic foot comes to about $485 a cubic yard, roughly three times the bulk price for this pad.
The plate-compactor rental is a garden centre's posted rate. Home Depot shows its own rental rate only after you pick a store.