How to replace a rotted section of a support beam
Replacing a rotten or splitting section of a wooden support beam resting on a foundation wall involves working directly under overhead floor joists. Because it is often unclear how serious the structural damage is, people usually need to consult an expert to evaluate the beam before attempting a fix.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Building/laminating pressure-treated lumber sandwiches with plywood
- 2Ripping down 2x12s to match dimensions
- 3Putting a piece of pressure-treated wood on either side of the beam
- 4Sistering a board behind it for peace of mind
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Hey all, have a wooden beam in my basement that has started to split. Wanted to get thoughts on how much of an issue this appears to be as I talk to my landlord about getting an expert out to look at it.”source ↗
“I am wanting to replace a 2’ rotten section of support beam on top of my foundation wall, under my floor joists.”source ↗
Where this came up
People with this problem also raised
- 5How to fix rotted wood landscape timbers
- 2Fascia board pulled away from rafters
- 7Do I need a structural engineer for a sagging floor beam?
- 2How to replace thin wood flooring in old, uneven houses
- 3How to handle a neighbor who won't pay for a shared fence
- 4Spot fix rotting wood siding or replace all of it?