What Happens If You Hit Large Obstructions While Digging Deck Footings?

When homeowners picture a deck being built, they usually imagine framing, decking, and railings — not what’s happening underground.

But some of the most important work happens below grade, and it’s also where surprises are most common.

For homeowners in Selinsgrove, Shamokin Dam, Sunbury, Northumberland, Lewisburg, and Danville, here’s what it means when large obstructions show up during footing excavation — and how they’re handled properly.

Why Obstructions Are So Common Below Decks

Once digging begins, we’re no longer working with drawings or assumptions — we’re working with actual soil conditions.

Common large obstructions include:

• Large rocks or boulders

• Old concrete footings or piers

• Buried construction debris

• Tree roots or old stumps

• Ledge or shallow bedrock

None of these are visible during a site visit, and many properties — especially older ones — have layers of history underground.

Why You Can’t Just “Dig Around” an Obstruction

When an obstruction is encountered, it’s tempting to:

• Move the footing slightly

• Dig shallower

• Pour concrete against the obstruction

However, footings must:

• Be placed according to the approved layout

• Reach required frost depth

• Bear on suitable, undisturbed soil

Simply digging around a large obstruction can:

• Reduce bearing capacity

• Create uneven support

• Lead to settlement or movement over time

That’s why obstructions must be addressed deliberately — not improvised around.

Common Ways Obstructions Are Handled

1. Removing the Obstruction

If feasible, large rocks or debris may be:

• Broken up

• Excavated and removed

• Replaced with properly compacted soil

This is often the cleanest solution, but it can require additional time and equipment.

2. Relocating the Footing (With Approval)

In some cases:

• Footing locations can be adjusted slightly

• Structural spacing must still be maintained

• Changes are coordinated with inspectors if required

Relocation is never done casually — spacing, loads, and design all matter.

3. Enlarging or Reengineering the Footing

When bedrock or immovable obstructions are encountered:

• Footing size may be increased

• Depth may be adjusted per code allowances

• Additional engineering may be required

The goal is always to achieve equivalent or greater load capacity.

4. Bridging or Redesigning Framing

Occasionally:

• Beam layouts are modified

• Spans are adjusted

• Load paths are redistributed

This requires experience and structural understanding — not guesswork.

How Inspectors View Obstructions

Inspectors understand that obstructions happen. What they care about is:

• Proper frost depth compliance

• Adequate bearing

• Code-compliant solutions

• Clear communication

When issues are addressed correctly and transparently, inspections typically proceed smoothly.

Why Obstructions Can Affect Schedule and Cost

While obstructions aren’t unusual, they can:

• Add excavation time

• Require additional labor or equipment

• Delay concrete placement

• Necessitate design adjustments

Good contractors communicate these issues immediately and explain options clearly — rather than pushing forward and hoping problems don’t show up later.

Why This Is Part of Responsible Deck Construction

Handling underground obstructions correctly:

• Protects long-term structural performance

• Prevents frost-related movement

• Avoids costly future repairs

• Ensures inspection approval

• Preserves homeowner peace of mind

It’s one of the less visible — but most important — aspects of a well-built deck.

Final Thoughts for Central Pennsylvania Homeowners

Large obstructions during footing excavation aren’t a sign of a bad project — they’re a reality of building in areas with long histories and varied soil conditions.

For homeowners in Selinsgrove, Shamokin Dam, Sunbury, Northumberland, Lewisburg, and Danville, understanding what happens below grade helps explain why careful planning, experience, and clear communication matter so much in deck construction.

When footings are handled properly, everything above them benefits.