Written by an AI agent working in this repository. Not financial or building advice. Every price here was read on 2026-10-29 from a search result's copy of the store's product page, some of them months or years old; the links in the tool are the check.
The person steering Shed Designer asked for the most realistic cost model it could give, with Home Depot and Lowe's gathered independently and compared. Here is what changed and what it says about the default 8x12.
A list a till would ring up
The shopping list now buys several things a real order needs:
- Spare boards. It adds 5% of each lumber size, rounded up, for warped or split boards and mis-cuts.
- Consumables the build steps already call for. These are subfloor adhesive, screws for the floor and door, flashing tape round the windows, and shims.
- Sales tax. It applies tax at a rate you set. The default is 7.53%, the Tax Foundation's 2026 average of combined state and local rates.
- Delivery, if you want it. Home Depot's $79 flatbed tier comes from a store page. Lowe's publishes no truck fee we could read, so you type it.
It also follows the steering person's own choices, made the same day:
- the door is built from the siding instead of bought prehung;
- the windows are the 14 x 21 shed window Home Depot sells;
- the skids sit on solid blocks set on tamped soil, with no crushed stone.
With those changes the default comes to $3,138.48 in materials, $3,374.81 with tax. The earlier default was $3,868 before spares and consumables, and $4,027 with them. Most of the drop is the $615 prehung door and the $300 of stone.
A "Have it" box takes anything you already own off what is left to buy. The person already has a roll of underlayment, so ticking it leaves $3,019.48.
Each store on its own
The Lowe's list was gathered separately from the Home Depot one. It has 75 listings with item or model numbers and links. Lowe's shows no price until you pick a store, so every Lowe's price came from a search result's copy of the page. Many of those copies are more than a year old, and the tool says how old where the result did.
Where Lowe's sells a different pack, the price is converted to the list's unit. For example, a 5 lb box of siding nails against the list's 1 lb box, or 105 ft of starter strip against 120 ft. Bulk prices apply once the quantity reaches them, such as Lowe's 2x4x8 at $3.61 each for 35 or more.
| Lines priced at that store | Whole list, other lines at the list price | |
|---|---|---|
| Home Depot | 44 of 48 | $3,121.68 |
| Lowe's | 35 of 48 | $3,024.60 |
| Menards | 11 of 48 | $3,267.32 |
On the 10 lines all three stores list, Lowe's is cheapest at $693.72, against $800.88 at Home Depot and $809.32 at Menards. The tool's "where to buy" advice puts Lowe's first. Picking up 20 lines at Home Depot as a second stop saves another $118.73, before the cost of the second trip.
Take the Lowe's figures with care. Several of its lumber prices come from copies more than two years old, and Lowe's says its stores do not honour online prices.
Your time has a price
There is now a labour rate, $50 an hour by default and adjustable. The tool turns a rough count of the work into hours. The count is minutes per cut, per member nailed, per connector, sheet, shingle bundle, trim board, block and opening. These are our own planning figures, and the table is in the source. The default 8x12 comes to about 36 hours.
The budget search now counts that time, which changes some answers. Birdsmouth notches instead of metal connectors save $81.34 of brackets, but cost about 0.7 hours of cutting. Counting the time, that is only $46.34, and the tool shows both numbers so you can choose.
What is next
Several directions are still open:
- a truss roof against the ridge beam, including a taller shed with trusses;
- interior volume against cost;
- snow loads for a Colorado winter, against the material the code minimum needs.