How much does it cost to underpin a house in Australia?

Do you live in a house that has a crumbling ceiling? Are your floor tiles chipping? Are you thinking of renovating your house and do not know where to start? Well, you are at the right place. Here we will discuss the process of underpinning a house , its cost, and the pros and cons attached to it. Let’s dive into it.

A house is a place that is supposed to protect you from harsh weather conditions. Therefore, your houses need regular maintenance . The purpose of the house dies if you have a crumbling ceiling and the floor tiles chipped at places.

A leaking ceiling is more of a health hazard than a safety net. It can fall anytime and cause casualties. Therefore, maintenance is key to a live-able house. If one upkeeps the house regularly, it will be light on pocket and there will not be any major problems.

Source: Structural Guide

What does underpinning a house means?

In simple terms, underpinning a house means raising its foundations. The process involves excavating the soil beneath and replacing it with foundation material which is usually concrete. However, it is not as simple as it sounds. The constructor needs to pay close attention to the design of the house. They also need to carefully select the methodology and choose the process that has no safety hazard.

Underpinning if done right, will not lessen the lifetime of your house and will last till the lifetime of the house. Therefore, if you do it at the right time, you can save a lot of money on maintenance.

underpin 2
Source: Global Reblocking

How do I know that my house needs underpinning?

There are several tell-tale signs of a house that needs maintenance. Some of them are:

  • Cracks in the walls.
  • Fallings windows due to cracks.
  • Building leaning to a side.
  • Diagonal cracking in the plaster.
  • Doors and windows not closing properly.
  • Dry soil.
  • Persistent water pools.
  • Jammed doors and windows.
  • Sagging in floor and ceiling.
  • Slopping floor and ceiling.
  • Unraveling floor.

Cost of underpinning a house:

The final cost of underpinning depends on the amount of work required. If foundation repair is required, it can cost around $5000 to up to $40000 depending on the extent of repair. However, if only underpinning is required, it can be done in as low as $5,000. Furthermore, if a large amount of work is required, underpinning can be quite expensive. The total cost can rise to as high as $80,000.

Below is a table summarizing underpinning cost:

Underpinning work Cost range
Moderate level foundation damage $9,000 - $13,000
Major level foundation damage $20,000 - $40,000
Pier replacement $1,000 per pier - $3,000 per pier
Foundation reinforcement $1,000 - $4,000
Simple foundation issues $500 - $1,000

Underpinning cost affecting factors:

Several factors contribute towards the final cost of underpinning a house. Some of the main underpinning cost influencing factors are:

  • Type of damage.
  • The extent of the damage.
  • Cause of the issue.
  • Type of foundation.
  • Ease of accessibility.
  • Labor.
  • Professional package.
  • Miscellaneous cost.

Causes of a failing foundation:

There are several causes of a failing foundation. If not repaired on time, it can lead to permanent damage. Some of the major causes of foundation failure are:

  • Mismanaged drainage system leading to moisture accumulation causing soil erosion and consolidation.
  • Leakage in underground pipes causing soil erosion.
  • Dry roots of trees can cause soil shrinkage under the foundation and damage them.
  • Soil shrinkage can also be caused due to extreme heat conditions. This will lead to the moving of house foundations above it.
  • Soil compaction not done properly can also ultimately badly affect the house foundations.

Building permit:

When going for building or underpinning, you need a building permit from the government. There is a different fee for different types of construction permits. Below is a table summarizing the cost of getting a construction permit:

Procedure needed Type of application Permit cost Type of work Cost of construction work to be done
Apply Application $400 Building permit Under $20,000
Apply Application $500 Notifiable building work Work of $20,000 or more
Apply Application $600 Building permit Cost of work between $20,001 and $200,000
Apply Application $1100 Building permit Cost of work between $600,001 and $1 million
Apply Application $1400 Building permit Cost of work between $1,000,001 and $7,500,000
Apply Application $800 Building permit Cost of work between $200,001 and $600,000
Apply Application $1500 Building permit Ost of work over $7,500,001
Comply Application $300 Notifiable building work Cost of work be less than $20,000
Vary Variation $400 Plan amendment
Vary Variation $300 Extension of building permit time

The permits need to be designed properly by a certified architect. It is to be made sure that the building work is done by a licensed builder having experience in the field. Lastly, the permit needs to be inspected by a qualified building surveyor.

Eligibility criteria for permit application approval:

Your application needs to fulfill certain criteria to be acceptable for a building permit. The eligibility criteria are as follows:

  • The application must be in the approved form.
  • All required documents should be complete and authentic.
  • One needs to provide details of public liability and worker’s compensation insurance.
  • The fee should be submitted beforehand.

Merits of underpinning a house:

  • Foundations are improved.
  • Structural integrity is maintained.
  • Enhancement in ceiling height.
  • Improvement in lighting.
  • Fixed plumbing, electrical fixtures, and insulation.
  • Rise in the resale value of your house.
  • Protects building from further damage.
  • Increases the liveable space.

Demerits of underpinning a house:

  • Quite an expensive process.
  • Getting a permit might be hard.
  • Excavation can be quite expensive.
  • It is a messy process.
  • Experiences labor is very expensive and hard to find.
  • Insurance might not cover the cost.

Bottom line:

If your house’s foundation is crumbling or you can see signs of it crumbling, you should consult a building professional immediately. If they provide underpinning as the only solution, then you should start the work for obtaining a permit straight away. If you find a foundation problem at the early stages and start the repair work, it will be light on your pocket and will not be very messy.