What’s Underpinning?
What is Underpinning?
Underpinning helps make a building’s foundation stronger and steadier. Sometimes, the original foundation can’t hold up the building well enough anymore, so it needs help.
Why Would You Need Underpinning?
- Soil Changes: Sometimes, the soil under your house can change and make the foundation weak.
- Damage from Disasters: Things like floods or earthquakes can hurt the foundation.
- Adding More Floors: If you want to add more floors to your house, the foundation needs to be stronger.
- Water Damage: Too much moisture can make the foundation weak over time.
Types of Underpinning
- Mass Concrete Underpinning: This uses concrete under the foundation.
- Beam and Base Underpinning: This uses beams to spread the weight.
- Mini-Piled Underpinning: Uses piles for deeper or hard-to-reach places.
Signs Your Basement Needs Underpinning
Look for These Signs:
- Cracks in Walls and Floors: Watch out for cracks. Vertical ones are not as serious but should still be watched.
- Sagging or Uneven Floors: If the floor has dips or slopes, the foundation might be failing.
- Doors and Windows Misalignment: If your doors or windows don’t close properly, it could be the foundation.
- Water Seepage: If water is coming into the basement, it can weaken the foundation over time.
Getting Ready for Underpinning
Check with a Professional
- Hire a Structural Engineer: They will tell you what’s wrong and how to fix it.
- Soil Testing: Find out what kind of soil is under your house.
Get Permits
- Local Building Codes: Make sure you follow the rules in your area.
- Applying for Permits: Ask your local authority for the paperwork you need.
How Underpinning Works
Mass Concrete Underpinning
- How It’s Done: Dig under the foundation and fill it with concrete.
- Pros and Cons: It’s simple but takes a lot of work, best for shallow foundations.
Beam and Base Underpinning
- How It’s Done: Beams spread the weight onto new bases.
- Pros and Cons: It works well but needs careful planning.
Mini-Piled Underpinning
- Best For: Deep foundations or hard-to-reach places.
- Pros and Cons: Can be used in many situations but costs more.
Steps to Underpin a Basement
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Dig the Soil
- Tools Needed: Shovels and diggers.
- Stay Safe: Use safety gear to prevent accidents.
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Add Supports
- Types of Supports: Concrete blocks or steel piers.
- Place Them Well: Make sure everything is aligned properly.
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Pour Concrete
- Make the Mix: Use the right mix for strong concrete.
- Keep it Moist: The area should stay wet so the concrete can set properly.
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Finish Up
- Waterproofing: Use sealants to keep water out.
- Backfill Soil: Put the soil back and pack it down.
Costs and Budgeting
What Affects the Cost?
- Basement Size: Bigger basements need more materials.
- Soil Type: Some soils are harder to work with.
- Method Used: Different methods have different costs.
Cost Range
Underpinning usually costs between $10,000 to $30,000.
Financing Options
- Home Equity Loans: Use your home’s value to get a loan.
- Personal Loans: These can help pay for the repairs.
Should You DIY or Hire Pros?
DIY: Pros and Cons
- Pros: Saves money and gives you a sense of accomplishment.
- Cons: Needs special know-how and tools, and mistakes can be costly.
Hiring Pros
- Find Good Contractors: Look for those who are licensed and insured.
- Ask Questions: Check their experience, timelines, and if they give warranties.
After Underpinning: Keep it Strong
Regular Checks
- Look for New Cracks: Find and fix them early.
Keep Moisture Away
- Use Sump Pumps: They keep the basement dry.
- Ensure Good Drainage: Water should flow away from the foundation.
Mistakes to Avoid
- Skipping Expert Help: Always get professional advice first.
- Ignoring Codes: Follow all building rules to avoid trouble.
- Using Cheap Materials: It weakens the project.
Success Stories
Real-life Examples
- Photos: Show before and after pictures.
- Testimonials: Hear from homeowners who’ve done it.
More Resources
Books
- "Foundation Repair Manual" by Robert Wade Brown.
Online Communities
- Reddit: Join forums about home improvement.
Professional Groups
- Canadian Association of Home and Property Inspectors (CAHPI)
This guide helps you understand how to underpin your basement so you can make good decisions about fixing your foundation.
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