Underpinning a house is a significant structural process, often necessary to stabilise and strengthen foundations when issues like subsidence arise. The cost varies widely based on factors like the method of underpinning used, the size and location of the property, and any unique challenges in the foundation or surrounding soil. Below, we’ll dive into the typical costs involved, regional cost variations, and the pros and cons of each underpinning method to provide a comprehensive cost guide.
In This Article
- Average Cost of Underpinning
- Cost Breakdown by Underpinning Method
- Additional Costs to Consider
- Regional Cost Variations
- Frequently Asked Questions
- Choosing an Underpinning Contractor
Average Cost of Underpinning
The cost of underpinning can range from £6,500 to £25,000, but this will depend on the underpinning method chosen, property size, and the condition of the foundation. The most commonly used method is mass concrete underpinning, which tends to cost around £13,500 for an average-sized UK property.
Cost Breakdown by Underpinning Method
Each underpinning method has its own associated costs, which vary based on complexity, materials, and labour. Below is a table summarising the cost of the most common underpinning techniques.
| Method | Cost per m² | Average Duration | Pros | Cons |
|---|---|---|---|---|
| Mass Concrete | £1,500 | 3-6 weeks | Cost-effective, minimal disruption | Time-consuming, limited depth |
| Beam and Base | £2,000 | 4-8 weeks | Stronger and stable than mass concrete | Limited by ground conditions |
| Mini-Piled | £2,600 | 5-10 weeks | Suitable for deeper foundations | Requires specialist equipment, higher costs |
| Expanding Resin | £1,200 | 1-3 weeks | Fast, non-disruptive, clean process | May not provide the same stability |
| Cantilever Needle | £2,000 | 3-5 weeks | Exterior method, minimal interior disruption | Requires substantial external space |
Additional Costs to Consider
Aside from the direct underpinning costs, homeowners may incur additional expenses related to labour, planning permissions, and inspections. Here's a breakdown of typical costs:
| Item | Average Cost |
|---|---|
| Structural Engineer (Initial Inspection) | £50-£90 per hour |
| Building Control Application | £150-£250 |
| Party Wall Agreement | Up to £1,000 per neighbour |
| Soil Investigation | £400-£600 |
| Tree Removal (if necessary) | £200-£300 |
| Reinforcement Rod Installation | £400 per metre |
| Wall Repair and Repointing | £120 per m² |
| Replacement Bricks | £15 per brick |
Regional Cost Variations
Location significantly affects underpinning costs. Below are rough cost estimates for underpinning in different UK regions:
| Region | Mass Concrete (per m²) | Mini-Piling (per m²) | Resin Injection (per m²) |
|---|---|---|---|
| London & SE | £1,800 | £3,200 | £1,400 |
| Midlands | £1,500 | £2,600 | £1,200 |
| North England | £1,300 | £2,400 | £1,000 |
| Scotland & Wales | £1,200 | £2,200 | £900 |
FAQ's
How can I tell if my property needs underpinning?
- Common signs include large cracks in walls, uneven floors, sticking doors/windows, and gaps between walls and ceilings. If you notice these signs, consult a structural engineer.
Is underpinning covered by home insurance?
- Most policies cover underpinning for subsidence but may have high excess costs. It's essential to check with your provider.
How long does underpinning take?
- It depends on the method. Mass concrete underpinning can take 3-6 weeks, while methods like mini-piling may require 5-10 weeks.
Can I underpin my house myself?
- Underpinning is a specialist job requiring structural expertise, planning permissions, and inspections. DIY underpinning isn’t recommended due to safety and insurance concerns.
What is the Party Wall Act, and does it apply to underpinning?
- The Party Wall Act requires you to notify neighbouring properties if you’re making structural changes that could affect shared boundaries. This includes underpinning work, and legal agreements can cost up to £1,000 per neighbour.
Choosing an Underpinning Contractor
When hiring a contractor, get multiple quotes and ensure they have insurance and relevant certifications. Membership in associations like the Association of Specialist Underpinning Contractors (ASUC) can offer added peace of mind.
Underpinning is a major investment, but by understanding the costs and carefully choosing the right method and contractor, homeowners can ensure their property remains safe, stable, and secure for years to come.
