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I am trying to look for a way to fix the sagging floor, have attached the picture, could any one give any leads or ideas?
Welcome to the Bunnings Workshop community @ffaisalb. It's sensational to have you join us, and many thanks for your question about a sagging floor.
To properly fix a sagging floor, the first step is to figure out what’s causing it. The most common issue is that the subfloor has either degraded over time or isn’t properly supported underneath.
Are you able to access the area under the house? If so, it’s worth having a look underneath to check for things like rotted or broken joists, sunken stumps, or missing supports. If you can identify the problem from below, you may be able to reinforce the structure and carefully jack the floor back to level.
If there’s no access from underneath, unfortunately, the only way to address it would be to remove the floor covering from above and inspect or replace the subfloor from that side. Once the cause is identified, you can then determine the best method for repair.
Please let me know if you have any questions.
Mitchell
Whats is the best material to use below, cement? Or mortar, please excuse my ignorance.
Faisal
Hi @ffaisalb,
It sounds like you might be looking for a product to fill the depression in the floor rather than lifting and reinforcing the structure underneath. In that case, a self-levelling cement compound could be used to even out the surface, but it’s really important to understand why the floor has sagged in the first place.
If the subfloor or joists underneath have degraded, or if there’s moisture damage, simply filling the dip won’t fix the underlying issue—and the problem could worsen over time. I’d strongly recommend engaging a professional to assess the subfloor and check for any signs of rot, structural movement, or dampness before proceeding. That way, you can be confident you're not just covering up a bigger issue.
Mitchell
Sorry, @ffaisalb. Just taking another look at your image, is it a concrete floor? I initially thought it was perhaps timber. If it's concrete, then it is unusual to be sinking in just one area. The flooring would typically be graded towards to floor drain, but having a sunken section in front of it is odd.
You might like to speak with a builder or concretor to get their thoughts.
Mitchell
Hello @ffaisalb
I agree with Mitchell's recommendation, I suggest getting a builder to investigate under your house to find out the cause of the sagging. Flooring does not sag without a reason, if the builder only says material failure, then you are lucky as it will just need to be replaced. But if there is any sort of moisture damage or leak involved, it will need to be addressed first before carrying any sort of repair first.
If you have any other questions we can help with, please let us know.
Eric
