Shed pier block count and spacing
Pier Blocks for Shed Foundation Calculator
Answer first: a 10×12 ft shed needs 6 pier blocks (4 corners + 2 mid-span). A 12×16 shed needs 9–12 blocks. Pier blocks are precast concrete deck blocks used for floating shed foundations. This calculator gives you the exact count, spacing, and optional concrete for custom piers.
10×12 shed (most common) — TuffBlock or precast pier
13 pier blocks (nrtechstudio 2026 reference)
Competitive calculator reference: 10×12 shed = 13 blocks/piers for a floating foundation. Estimated material cost: ~$162. TikTok creators confirm TuffBlocks are the easiest option — lightweight, no digging, leveling adjustability.
10×20 ft shed (home office + storage)
11 pier blocks (Reddit engineer plan)
Reddit r/HomeImprovement: 10×20 ft shed = 4 corners + 2 mid each 20-ft side + 2 mid each 10-ft side + 1 center = 11 piers. "Smaller spacing allows smaller beams — typically sized to minimize cost and allow rapid construction."
12×16 ft shed
9–13 pier blocks
9 blocks minimum (3×3 grid) for typical loading. 12–13 for heavy storage or workshop. Place at 4-ft max spacing. Larger sheds need 3 beam rows, each supported every 4–6 ft.
Soil load capacity (engineering reference)
Standard soil = 2,000 lbs/sq ft
Reddit structural engineer: "You can assume dirt can support 2,000 lbs per square foot." A 12-in pier block has ~0.75 sq ft = 1,500 lb capacity per pier. Design your layout so total load ÷ pier count stays under this limit.
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How many pier blocks do I need for a shed?
Quick reference: 8×10 ft shed = 4–6 blocks. 10×12 ft = 9–13 blocks. 12×16 ft = 9–13 blocks. 10×20 ft = 11+ blocks. The exact count depends on joist span, beam spacing, and your local code. The rule is: pier blocks no more than 8 ft apart, with 4–6 ft preferred. Add one pier at every corner, plus mid-span support every 4–6 ft along each beam.
What is a TuffBlock and is it better than standard pier blocks?
TuffBlocks (and similar adjustable deck blocks) are precast plastic-composite pier supports with a built-in adjustable top that holds a 4×4 or 2×6 joist. TikTok DIYers love them for three reasons: (1) no digging required, (2) the adjustable top makes leveling easy, (3) they are lightweight to carry. They cost $15–$25 each vs $3–$8 for a standard concrete deck block. For a small shed where leveling is challenging, TuffBlocks are worth the premium.
How far apart should pier blocks be for a shed?
Pier blocks should be spaced 4–8 ft apart maximum. Reddit engineers confirm: "Some say 8-10 ft, others say 5-6 ft — the right answer is to minimize cost while meeting code." For 2×6 floor joists, 6 ft max span is safe. For 2×8 joists, 8 ft max is acceptable. Using closer spacing (4 ft) allows smaller, cheaper beams. A 10×20 ft shed typically needs 11 piers at roughly 4-6 ft spacing.
Do I need a permit for a shed on pier blocks?
Most US jurisdictions allow sheds under 100–200 sq ft on a floating pier block foundation without a permit. Common thresholds: 100 sq ft (some cities), 120 sq ft, 144 sq ft, or 200 sq ft. A floating foundation (pier blocks on gravel, not in ground) is treated as temporary in many codes. Always check with your local building department — permit requirements vary significantly by city, county, and state.
What size pier blocks should I use for a shed?
The most common sizes: Standard 8×8×4 in precast concrete deck block: handles most sheds, costs $3–$8. 11×11×4 in deck block: for 6×6 posts or heavier loads. TuffBlock adjustable: 4×4 or 2×6 slot, adjustable 2 in, $15–$25. Tube form + concrete (10–12 in diameter): for below-frost footings, most permanent. For sheds under 200 sq ft, standard 8-in deck blocks are almost always sufficient.
How do I calculate soil bearing capacity for a shed foundation?
From Reddit structural engineer: "Standard soil can support about 2,000 lbs per square foot." To check your design: (1) Calculate total shed load = floor area × (20 psf dead + 40 psf live + local snow load). For a 10×20 ft shed with 70 psf snow: 200 × 130 = 26,000 lbs. (2) Divide by number of piers × pier area. 11 piers × 0.75 sq ft each = 8.25 sq ft total. 26,000 ÷ 8.25 = 3,151 lbs/sq ft — OVER the 2,000 limit, so add more piers or use larger blocks.
What is the difference between pier blocks, deck blocks, and tube forms?
Three types of shed pier supports: (1) Precast concrete deck blocks (8×8 in flat): fastest, cheapest ($3–$8), surface level only. (2) TuffBlocks/adjustable pier blocks: easy leveling, more expensive ($15–$25). (3) Concrete tube forms (Sonotubes, 8–12 in diameter): go into the ground, below frost line, permanent — required by some codes for larger sheds. Use deck blocks for small floating sheds, tube forms when frost heave or permits require below-frost depth.
How many pier blocks for a 10×12 shed?
A 10×12 shed needs 9–13 pier blocks for a floating foundation. Minimum layout: 4 corners + 1 mid each short side + 1 center each long side = 9 blocks. For a sturdier floor: 4 corners + 2 mid each 12-ft beam + 2 mid each 10-ft beam + 1 center = 13 blocks. The competitive calculator reference (nrtechstudio 2026) shows 13 piers/blocks for a 10×12 at estimated material cost of $162.
How many pier blocks for a 12×16 shed?
A 12×16 shed needs 9–13 pier blocks. Standard layout with 2 beam rows: 4 corners + 2 mid each 16-ft beam + 2 mid each 12-ft beam + 1 center = 9 piers minimum. For 3 beam rows (wider shed): 4 corners + 2 per beam row (3 rows × 2) + 3 along each short end = 13 piers. For heavy storage or workshop use, go to 4-ft spacing which gives about 12–15 piers total.
What goes under pier blocks to prevent sinking?
Always place pier blocks on a stable, level surface: (1) Compacted gravel (4–6 in of crushed stone): best option — drains well, prevents frost heave under the block. (2) Paver or concrete pad: level and stable, good for firm soil. (3) Native soil: only if firm, well-drained, and undisturbed. Avoid soft or clay soil under pier blocks — it settles and shifts. TikTok shed builders confirm: digging out 4–6 in and backfilling with gravel is worth the extra work.
What are the 4 types of shed foundations?
Four options (from most to least expensive/permanent): (1) Concrete slab: most permanent, requires excavation, best for large sheds. (2) Concrete pier blocks or tube forms: strong, allows airflow, can be below frost line. (3) Compacted gravel pad: cheapest, excellent drainage, easy DIY. (4) Pressure-treated skids: simple, can be moved, lowest cost but shortest lifespan. Competitive calculator (nrtechstudio) shows gravel pad is often cheapest for small sheds — pier blocks give the driest floor.
Planning disclaimer
Pier block counts are general guidelines. Actual requirements depend on shed weight, floor joist size, soil bearing capacity, and local building codes. Check local permit requirements before construction.