How to repair rotten timber door frame near shower?

[RickyYuan]

Hi,

I'm repairing a rotten door frame near the shower, and it looks like the water damage has been there for quite a while. My initial plan is to cut out the bottom section, replace it with a new piece of timber, then sand and repaint.

Before I go ahead, I’d love to hear if anyone has a better solution or any tips—especially to help prevent the new timber from rotting again. Would waterproofing the wall behind the frame help? What products should I consider?

Any advice would be much appreciated!

[MitchellMc]

Hi @RickyYuan,

From the location of the rot, I’d suggest there’s likely a leak at the inside corner of the shower hob—water is probably escaping past that junction and seeping into the wall and door frame over time. To prevent this from happening again, it’s important to seal the inside of the hob properly. You can do this by applying a quality wet area silicone to fill any gaps in the tile joints where water might be getting through. Just make sure the area is clean and dry first for good adhesion.

As for repairing the frame, rather than trying to graft in a small section of new timber, it’s often just as easy—and more effective—to remove the entire piece of trim on that side and replace it. That way, you’ll get a cleaner finish and have a better chance to inspect the timber behind for any hidden water damage.

Waterproofing the wall behind the frame won’t really help if the water is getting past the shower hob in the first place. The key is to stop water from escaping the shower area entirely with proper sealing. 

Please let me know if you have any questions.

Mitchell

[RickyYuan]

Hi Mitchell,

Thanks so much for the reply! I’ll definitely seal the internal corner as you suggested.

Regarding the trim replacement—could you please explain a bit more about how to do it? This door frame has a rounded profile on the outer edge, so I’m wondering if there’s a similar moulding available at Bunnings that I can use to match it.

[JacobZ]

Hi @RickyYuan,

That timber profile is known as bullnose. It is extremely common, so you shouldn't have trouble replacing it. Just make sure you match the dimensions of the old trim, and the rounded edge should match up. 

To replace it, you would pry the old piece off with a pry bar, do any required repair work to the framing, cut your new piece to length, attach your trim piece to the framing with a trim nailer, fill the nail holes with spakfilla, seal the edges with Selleys White No More Gaps Bathroom And Kitchen Gap Filler, then prime and paint.

If you don't have access to a trim nailer, they can be hired through our hire shop - For Hire: Trim Master Gas Bradder.

Each step is relatively simple to do; do things one after the other, and it is a relatively simple repair.

Let me know if you have any further questions.

Jacob