There are a number of factors to plug into that algorithm.
How Old or how New is my house
What is the average value of similar houses to mine…top sale price ..bottom sale price
How long am I intending to stay in this house 1 year….20 years
Am I an investor who just wants to flip the house or a home maker
Are the foundation defects noticeable to your friends…wall cracks…uneven floor levels..sticking doors….how bad…scarey?
Are the foundation problems suddenly getting worse now or just continuing slowly to get worse.
When a house gets built the average cost of the foundations are about 20% of the build cost which gives you an idea of their value and maximum renovation/repair expenditure. AS with any repair works you can do a quick and nasty job or a job which would comply with current building standards, or a premium job of fully protecting the home for a long time into the future.
An older home would have been built to a lesser standard and so expectantly demonstrate more signs of foundation failures. So more costly on average to repair if defects are showing.
An older house purchaser has some tolerance for defects which you won’t find in a relatively new house buyer. They have a much lesser of a tolerance for even minor defects. So a point to consider in your deliberations. The nature of the defect eg 1mm crack in the external brickwork could easily miss the eye of the purchaser but a 20mm crack could well be a sale breaker.
Then there is the length of time you plan to live with the house which determines for many to do a quick nasty job to cover up the defects with out really fixing and hoping to pass these onto the unwitting purchaser. If you plan on keeping the property the argument to do a good repair job becomes much stronger and economic solution.
These are some of the factors to consider in your optimum economic solutions
To get confirmation of your decision on how much to spend on foundation repair you can consult with your local agent, builder, underpinner from which you can build a consensus of opinion.
For more information about foundation repairs see bestunderpinning.com.au