Underpinning vs Benching: Which is Best for Your Basement?

Choosing between underpinning and benching (bench footing) is one of the most important decisions you'll make when lowering your basement. This comprehensive guide compares both methods to help you make the right choice.

Introduction

When lowering your basement floor, you have two main methods: underpinning and benching. Each has distinct advantages, costs, and use cases. Understanding the differences will help you choose the best option for your home and budget.

What is Underpinning?

Underpinning extends your foundation walls deeper into the ground, creating a new foundation level below the existing one. The entire basement floor is lowered uniformly, providing full ceiling height throughout.

How Underpinning Works

1. Excavation: Workers dig beneath the existing foundation in sections
2. Foundation Extension: New concrete is poured to extend walls deeper
3. Support: Temporary supports hold the structure during work
4. Completion: Entire basement floor is lowered uniformly

Key Characteristics

1. Full ceiling height throughout basement
2. Uniform floor level
3. Extends foundation walls deeper
4. More extensive structural work
5. Higher cost but better results

What is Benching (Bench Footing)?

Benching creates a step-down area in your basement without extending the foundation walls. Only part of the basement floor is lowered, creating an uneven floor level with a "bench" or step.

How Benching Works

1. Partial Excavation: Only the center area is dug out
2. Bench Creation: A concrete bench is created around the perimeter
3. Step-Down: Floor is lowered only in the center area
4. Completion: Uneven floor levels remain

Key Characteristics

1. Uneven floor levels
2. Step-down in center area
3. Foundation walls remain at original depth
4. Less structural work required
5. Lower cost but limited headroom

Side-by-Side Comparison

Cost Comparison

| Factor | Underpinning | Benching | |--------|-------------|----------| | Cost per sq ft | $75-$150 | $50-$100 | | Typical 1000 sq ft | $100,000-$150,000 | $60,000-$100,000 | | Timeline | 8-12 weeks | 4-6 weeks | | Complexity | High | Medium |

Ceiling Height

Underpinning:

1. ✅ Full ceiling height throughout (8-9 feet)
2. ✅ Uniform height everywhere
3. ✅ Meets code for legal apartments
4. ✅ Better for finished basements

Benching:

1. ⚠️ Uneven ceiling heights
2. ⚠️ Lower height near walls (6-7 feet)
3. ⚠️ May not meet code requirements
4. ⚠️ Limited finishing options

Structural Impact

Underpinning:

1. More extensive foundation work
2. Requires structural engineering
3. Stronger foundation overall
4. Better long-term stability

Benching:

1. Less foundation modification
2. Simpler engineering requirements
3. Foundation walls unchanged
4. Adequate for most applications

When to Choose Underpinning

Choose underpinning if:

✅ You want a legal basement apartment

1. Requires minimum 6'11" ceiling height
2. Uniform height throughout
3. Meets all building code requirements

✅ You plan to finish the basement

1. Better for drywall and ceilings
2. Uniform floor level
3. Professional appearance

✅ You want maximum headroom

1. Full ceiling height everywhere
2. No awkward low areas
3. Better for tall furniture

✅ Budget allows for higher cost

1. Higher initial investment
2. Better long-term value
3. Increases property value more

When to Choose Benching

Choose benching if:

✅ Budget is a primary concern

1. Lower initial cost
2. Good value for money
3. Faster return on investment

✅ You only need partial lowering

1. Don't need full basement lowered
2. Specific area requirements
3. Limited use case

✅ You need faster completion

1. 4-6 weeks vs 8-12 weeks
2. Less disruption
3. Quicker project completion

✅ Foundation walls are in good condition

1. Don't need extensive foundation work
2. Adequate existing foundation
3. Simpler project scope

Cost Breakdown

Underpinning Costs

Base Cost: $75-$150 per square foot

1. Excavation: $15,000-$40,000
2. Foundation work: $40,000-$80,000
3. Engineering & permits: $5,000-$10,000
4. Waterproofing: $8,000-$20,000

Total for 1000 sq ft: $100,000-$150,000

Benching Costs

Base Cost: $50-$100 per square foot

1. Partial excavation: $10,000-$25,000
2. Bench construction: $20,000-$40,000
3. Engineering & permits: $3,000-$6,000
4. Waterproofing: $5,000-$15,000

Total for 1000 sq ft: $60,000-$100,000

Building Code Considerations

Toronto Building Code Requirements

Legal Basement Apartment:

1. Minimum ceiling height: 6'11" (2.1m)
2. Uniform height required
3. Underpinning typically required

Habitable Space:

1. Minimum ceiling height: 6'5" (1.95m)
2. Benching may meet requirements
3. Depends on specific area

Important: Always check with your contractor and city building department to ensure your chosen method meets code requirements.

ROI Comparison

Underpinning ROI

1. Property value increase: 60-70% of project cost
2. Rental income potential: $1,500-$2,000/month
3. Payback period: 5-7 years via rental income
4. Resale value: Higher premium

Benching ROI

1. Property value increase: 40-50% of project cost
2. Rental income potential: Limited (may not be legal)
3. Payback period: 7-10 years
4. Resale value: Lower premium

Common Questions

Can I convert benching to underpinning later?

Yes, but it's expensive. Converting benching to underpinning essentially means doing the underpinning work anyway, so you'd pay for both methods. It's better to choose the right method initially.

Does benching affect resale value?

Yes, benching typically adds less value than underpinning because:

1. Uneven floor levels limit use
2. May not meet code for legal apartments
3. Less appealing to buyers

Which method is safer?

Both are safe when done by licensed contractors. Underpinning involves more structural work but creates a stronger foundation overall.

Can I do underpinning myself?

No. Both methods require:

1. Structural engineering
2. Building permits
3. Licensed contractors
4. Specialized equipment
5. Insurance coverage

How do I decide?

Consider:

1. Budget: Can you afford underpinning?
2. Goals: Do you need a legal apartment?
3. Timeline: How quickly do you need it done?
4. Future plans: Will you finish the basement?

Making Your Decision

Choose Underpinning If:

1. Budget allows ($100K+)
2. You want a legal basement apartment
3. You plan to finish the basement
4. You want maximum property value increase

Choose Benching If:

1. Budget is limited ($60K-$100K)
2. You only need partial lowering
3. You need faster completion
4. You don't need uniform ceiling height

Get Expert Advice

The best way to decide is to consult with experienced contractors. They can:

1. Assess your specific situation
2. Provide accurate cost estimates
3. Explain code requirements
4. Recommend the best method

Conclusion

Both underpinning and benching are valid methods for lowering your basement floor. Underpinning provides better results but costs more. Benching is more affordable but has limitations. Your choice depends on your budget, goals, and specific needs.

Get Your Free Consultation

Ready to lower your basement? Use our cost calculator to compare costs, or contact us for expert advice on which method is best for your project.

About HomeRise

HomeRise specializes in both underpinning and benching methods. We'll help you choose the right approach for your home and budget. Learn more about our services.