How many deck blocks do I need for a 10X10 shed?

When building a 10×10 shed, one of the most important considerations is determining how many deck blocks you will need for the foundation. Deck blocks provide a stable, level base for your shed and help prevent sinking or shifting over time. Choosing the right number of deck blocks is essential for proper shed construction.

Quick Answers

– For a basic 10×10 shed with 4×4 or 4×6 skids, you will need approximately 25-30 deck blocks.
– If using 6×6 skids, around 20-25 deck blocks are needed.
– Wider skids like 8×8 require 15-20 deck blocks for a 10×10 shed.
– Deck blocks should be spaced every 2-3 feet along the skids.
– You’ll need additional blocks for corners and door openings.
– Other factors like soil type, shed size, and weight impact block quantity.

In this article, we will provide a detailed overview of how to calculate the ideal number of deck blocks for your 10×10 shed build. We’ll discuss skid size options, deck block spacing, corner and door reinforcements, soil considerations, and shed weight. We’ll also provide some examples and general guidelines to help you determine exactly how many blocks you need to properly support a typical 10×10 shed.

What Are Deck Blocks?

Deck blocks, also sometimes called pier blocks, are concrete masonry units used to support and level shed foundations. Deck blocks have a wide, flat top surface and are typically 6, 8, 10, or 12 inches high. They are designed to bear heavy vertical loads and keep sheds stable over time.

Deck blocks provide many advantages over other shed base options:

  • Pre-formed concrete construction gives excellent compression strength.
  • Built-in vibration/shock resistance.
  • Won’t rot, rust, or degrade like wood.
  • Provides protection against frost heave when below frost line.
  • Allows simple leveling and adjustment.
  • Low maintenance.

Using deck blocks is generally simpler, cheaper, and longer-lasting than constructing a full poured concrete slab or foundation. They also allow the shed to be portable if relocation is ever needed.

Sizing Deck Blocks

Deck blocks for shed foundations are commonly available in the following sizes:

  • 6 in. x 6 in. x 6 in.
  • 8 in. x 8 in. x 6 in.
  • 10 in. x 10 in. x 6 in.
  • 12 in. x 12 in. x 6 in.

The larger the block, the more weight it can support. For most 10×10 sheds, the 6 in. or 8 in. size deck blocks will be sufficient. Larger sheds may require the 10 in. blocks. The typical weight capacity per block is:

  • 6 in. block – 1,000 to 1,500 lbs
  • 8 in. block – 2,000 to 2,500 lbs
  • 10 in. block – 3,000 to 3,500 lbs
  • 12 in. block – 4,000 to 4,500 lbs

Make sure the deck blocks selected are rated to handle the total anticipated weight of the shed and contents. Also consider increasing frost depth for colder climates.

Shed Skids

Deck blocks support the shed via skids or runners around the base of the frame. Typical skid dimensions are 4×4, 4×6, 6×6, or 8×8 pressure treated lumber. The skids bear the shed’s weight and keep the floor frame elevated off the ground.

Some advantages of using skids include:

  • Makes the shed portable for relocation.
  • Allows easy leveling across uneven ground.
  • Provides space for anchoring into the deck blocks.
  • Increased lifespan versus wood in direct ground contact.
  • Allows underlying vegetation control.

The skid size impacts the number of deck blocks needed. The general recommendation is:

  • 4×4 skids – 25-30 blocks
  • 4×6 skids – 25-30 blocks
  • 6×6 skids – 20-25 blocks
  • 8×8 skids – 15-20 blocks

Wider skids allow for more spacing between blocks. The tradeoff is cost, with larger skid lumber being more expensive. 4×4 or 4×6 skids are usually sufficient for 10×10 sheds under 500 sq. ft.

Deck Block Spacing

Proper deck block spacing helps distribute the shed’s weight evenly and prevent sagging or distortion of the floor over time. Recommended spacing is:

  • Light sheds – Blocks every 4-5 feet
  • Medium sheds – Blocks every 3-4 feet
  • Heavy sheds – Blocks every 2-3 feet

Closer block spacing is needed for heavier sheds or contents. For a 10×10 shed, spacing blocks every 2-3 feet around the perimeter is ideal for stability. This works out to 6-8 blocks along each 10 ft skid.

Make sure blocks are also placed near the corners and midpoint of each skid. Avoid large gaps without support. Having a block under joints between skid lumber is also recommended.

Shed Weight Considerations

The contents of your 10×10 shed will determine how much total weight needs to be supported. Some common factors include:

  • Building materials – Heavier shingles, bricks, concrete blocks, etc. add weight.
  • Stored items – Lawn tractors, ATVs, and other vehicles are very heavy.
  • Work benches – Sturdy fixed benches with tools can weigh several hundred pounds.
  • Shelving – Shelves alone may weigh 50-100 lbs each when loaded.

All these factors should be considered when planning deck block quantity and spacing. A good rule of thumb is to estimate 10 lbs per square foot for an empty wood shed. This equals 1,000 lbs for a basic 10×10 shed frame and roof.

Add 500-1,000 lbs for a riding lawnmower or ATV. Several hundred more for fixed benches and shelves. Miscellaneous tools and supplies can add weight quickly.

For heavy 10×10 sheds exceeding 2,000 total lbs, choosing 8×8 skids with blocks every 2 ft is a safer bet. You want the blocks and soil to be able to handle peak loads without shifting or settling issues.

Soil Conditions

The type of soil on your site impacts the load capacity for deck blocks. Basic soil strength profiles are:

Soil Type Load Capacity (lbs per sq ft)
Hard clay 5,000
Sandy clay 4,000
Sandy loam 2,000
Peat 1,000

sites with soft, loose, or organic soils may not offer enough support. In this case, a gravel foundation pad or other improvements should be made before installing deck blocks. You can dig test holes to check the soil consistency on your site.

Also avoid steep slopes or grades when siting the shed, as the blocks can more easily shift downhill. try to locate sheds on flat or gently sloping areas for best stability.

Reinforcing Corners and Door Openings

When calculating block quantity, be sure to account for extra blocks needed at corners and door openings.

Each corner of the shed should have an additional block for reinforcement. If using angled corner skids, have one block at each end plus one in the center. This helps brace the corners from multidirectional forces.

For sheds with doors, especially large double doors, add 1-2 extra blocks next to the door framing. The door opening disrupts the perimeter skid, requiring additional support.

Having an extra 2-3 blocks at the corners and doors helps strengthen these high-stress areas.

Example Deck Block Layout

Let’s look at a sample deck block installation for a 10×10 shed:

  • 4×6 perimeter skids
  • 6 in. x 6 in. x 6 in. deck blocks
  • Shed weight ~1,000 lbs
  • Firm clay/loam soil
  • 5×5 ft double door opening centered on 10 ft wall

Sketch of recommended deck block layout:

Corner X Corner
Corner X Corner

This layout shows:

  • Blocks spaced every 3 ft along skids
  • Extra blocks at the 4 corners
  • 2 extra blocks adjacent the door opening

With approximately 7 blocks per side plus 4 corner and 2 door blocks, the total for this shed comes to:

7 blocks x 4 sides = 28

4 corner blocks = 4

2 door blocks = 2

Total blocks = 28 + 4 + 2 = 34

This number of properly spaced 6x6x6 in. deck blocks should provide a stable foundation for a standard 10×10 shed in firm soil conditions.

General Guidelines

To recap our recommendations for how many deck blocks are needed for a 10×10 shed:

  • Use 6x6x6 in. or 8x8x6 in. blocks for best support.
  • Choose skids sized 4×4 to 8×8 based on total shed weight.
  • Space blocks every 2-3 feet along skids.
  • Add 1-2 extra blocks at corners and door openings.
  • 25-30 blocks total for lighter sheds.
  • 20-25 blocks total for heavier sheds.
  • Adjust for soft soil by spacing blocks closer or improving base.

Carefully planning your deck block layout and using enough blocks is crucial to building a stable, level 10×10 shed foundation. Investing in the right quantity and quality of blocks upfront will pay off for years to come.

We hope these guidelines give you a good starting point for determining your deck block needs. Double-check your shed design plans and consult local building codes for any additional requirements. Feel free to calculate the blocks more precisely based on exact skid lengths and door placement when preparing to build. With the right preparation, you’ll be well on your way to a sturdy, lasting shed foundation.

Leave a Comment