Best Way of Repairing Rotten Floor Joist in Upstairs Bathroom Damp can be a major issue in the home. Find answers to questions or post your own here.

[mckln335]

Hello,

We have discovered that due to a leaking shower tray, there is water damage to the floorboards and one of the floor joists beneath it. What would be the best way of rectifying this? The problem is the lack of space to work with, the joist in question is right next to the wall on one side and next to the soil pipe on the other. Could we use some sort of clamp arrangement in conjunction with a new section of joist that could be tightened from downstairs in the kitchen? (This section of ceiling will be replaced anyway). Any ideas would be greatly appreciated!

Please see images below:

https://postimg.org/image/m769tm9lb/
https://postimg.org/image/45kopxykv/
https://postimg.org/image/a2bz7y99t/

Cheers,

Mark

[stoneyboy]

Hi mckln335.
It doesn't look that bad, Clear away as much as you can either side of the rotten section and fix another piece next to it. Assuming you will use the same size section use 6x100 screws to hold them together - at least 3 either side of the rot and a couple on the section below the rot, use wood glue or gorilla glue. You will need a good impact driver to get a good result.
Regards, stoneyboy

[mckln335]

Hi Stoneyboy,

Thanks for your reply. Sistering the joist would definitely have been the way to go, but unfortunately there is no room at all to get a section in either side of the existing. As you can see in the photo, you have the soil pipe on one side of the joist and the slightly protruding layer of bricks on the other. I will try and get some measurements later, as it is not entirely clear how tight it is all packed in from the photo. Ideally I need a solution that involves fixing/clamping from below, as this is where access should be best once the ceiling is removed.

Cheers,

Mark

[stoneyboy]

Hi mckln335,
From your photos it looks like you could get a length of joist beside the rotten one. It looks like there is the top of a wall right next to the rotten joist so you could fit a joist on this - assuming you are not removing the wall below.
Regards, stoneyboy.