Written by an AI agent working in this repository. Not engineering or building-code advice. Prices are store listings read on 2026-10-29, mostly from search results. They move.
On 2026-10-29 the owner and a builder walked through Shed Designer for a shed they plan to build. It has to stay under 100 sq ft so it needs no permit where they live. It gets shingles and painted lap siding to match the house. And it should store as much as possible for as little as possible. They also asked for designs they could flick through and start from, instead of a blank page. The tool now opens with ten.
Where the ten come from
No card was typed in by hand. The tool's design search (designsearch.mjs) builds whole sheds and frames, prices and checks each one. It varies:
- the size and which way the ridge runs;
- the door and window layout;
- the roof frame, pitch, overhang and wall height;
- the framing sizes and spacing;
- the foundation, floor, siding and roofing.
It ran twice, 1,200 designs each time. The first run was free to change every finish. The second kept painted fiber cement lap siding and shingles, the HardieBoard-house look.
A design is kept only if it meets all four of these limits:
- every member is at 90% of its capacity or less (a shed is exempt from the house code, so members are sized by the checks, with a margin, not by house habit);
- the model raises no warning about it;
- it is under 100 sq ft;
- it peaks at 13 ft or less.
The first run kept 898 of its designs. The second kept 852.
Each card then takes the best kept design on one measure:
- cheapest;
- most room per dollar;
- the balance of cost, room and looks;
- most storage;
- best looking;
- matching the house;
- cheapest lap-sided;
- a 10x10;
- a long one;
- one with a 48" door for a mower.
No two cards are the same shed, and each card prefers a size the earlier cards don't show. When that pushes a card off the overall winner, its reason says "in a size the cards above do not show" instead of claiming first place. A test re-runs both searches and checks every reason against them.
The height limit mattered
The first version had no peak limit. Its roomiest designs were 16 ft gable spans with the ridge only 6 ft long, a 9/12 roof and a 15'8" peak. The search was right that this holds the most, 896 cu ft. But it is not a shed anyone would put next to a fence. The search's own default cap of 13 ft now applies. With it, the most storage is a 7x14 holding 783 cu ft, with a peak of 12'8".
An earlier version, built on the simpler cost search, needed two more limits. Without a margin, two of its designs ended with a check at exactly 100%. Without a no-warnings rule, seven used 2x4 rafters notched more than a third of their depth, and two dropped their gable vents to save money. Leaving out a part the design called for is not a saving. Both limits carried over.
None of them reaches $2,000
The owner's budget is about $2,000 in materials. Of the 1,750 designs the two runs kept, none comes in under it.
The cheapest of all is an 8x10 at $2,288.04 before tax. It has LP SmartSide panels, a metal roof, a door in the gable end and no windows. The cheapest with lap siding and shingles is also an 8x10, at $2,602.05. This is where the $2,288.04 goes:
| Section | Cost |
|---|---|
| Lumber | $497 |
| Siding | $490 |
| Roofing | $389 |
| Fasteners and sealants | $229 |
| Sheet goods | $142 |
| Foundation and hardware | $142 |
| Roof trim | $114 |
| Wall trim | $110 |
| Paint | $100 |
| Door hardware | $39 |
| Site prep | $37 |
Siding costs nearly as much as the lumber, and fasteners cost more than the sheet goods. In the lap-sided version, siding rises to $731, because fiber cement planks go over a layer of OSB sheathing. Getting near $2,000 will take what this search does not change: buying fasteners by the pound, not the box, and a cheaper wall skin.
The figures are screening numbers from the tool's own checks, not an engineer's review. Your town decides what needs a permit, and how tall a shed may be.