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How to repair wood rot and re-seal window sill?

finn2018

Hi Everyone,

How can I go about repairing this window sill of wood rot?

Screenshot 2024-09-23 at 11.16.10 AM.png

I've read through this article which was very helpful and also purchased Turbo Timer Rot Repair Kit, however, as it's inside, I would hope to use builders bog that is stainable so it can match the rest of the frame (picture 2).
We've also bought Selley's Roof and Gutter Sealant.

Screenshot 2024-09-23 at 11.17.04 AM.png

It seems like I would also need to reseal the glass at the bottom to prevent more water seeping through. How do we prep the area and what is the best method?

The windows seem to have this between the glass pane and sill (from another window):

Screenshot 2024-09-23 at 11.59.45 AM.png Screenshot 2024-09-23 at 12.00.02 PM.png

(I've also checked the wood of this sill and it's hard, and seems to just be surface level water stains that are in need of re-staining)

Any tips would be greatly appreciated!

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Comments

EricL

Hello @finn2018

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about re-sealing your window sill.

Just a friendly reminder that working around glass is dangerous and an accidental hit or a sanding tool pushed too hard could shatter the glass and cause injury. Please take extreme care when working around glass. Please remember to wear personal protection such as thick gloves, goggles and a mask when working on your project.

The general steps would be to sand the timber surface to remove the old layer that has dried up and faded. Next is to test which part of the timber has rotted, tap the surface with a screwdriver to see which parts are brittle and have given way. The rotted parts need to be removed, but if too much of the timber has been compromised the frame will need to be replaced. At the moment, I don't recommend removing the thin filler that is currently next to the glass as it is keeping it in place.

On the condition that the frame is still in good condition and can be repaired the next step would be to use the builders bog to fill the damage. I suggest painting the bog in a dark brown colour close to the finish you're after before staining the timber. In regards to the thin timber filler, I propose engaging the services of an experienced handy person or builder who might be able to recognize what that material is.

I recommend using the Sika 300ml Sikaseal 300 Glass And Weather Seal Silicone Sealant - Transparent outside to seal the glass.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let me know.

Eric

Dave-1

Morning @finn2018

Welcom to the Bunnings Community pages 🙂 If you take a stroll through here there are a bunch of differeant types of ways that you could step through your window issue.

I agree with the steps @EricL has suggested.

Do you have a photo of the outside of the window? The rot dosnt look too bad but I was trying to work out the windows edge from your photo and how the water entered to cause the rot.

Dave

Nailbag

Hi @finn2018

I agree with your latest photos that the inside frame appears to be stained from moisture/water most likely getting in from a deteriorating external window seal. The overall surface just looks sun damaged requiring a good sand back and a couple of coats of a quality timber oil.

From the external photo, again the timber looks very sun damaged requiring a lot more work in the sanding dept.

Without a couple of wider angle shots to know for sure, but those broken pieces in the photo could be some type of filling packer used to press the glass up against the frame. Water is possibly pooling in this channel causing the water stains. Removing and cleaning the channel out and using the Sika sealant @EricL recommended.

Regards, Nailbag

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