Replace timber door threshold/sill

[alex27]

Hello everyone,

I am looking for some recommendations or ideas on how to replace an external laundry door threshold/sill.

I attached few photos. As you can see on the photos, it is completely damaged and rotten. 

Because it is an external door, it is always exposed to rain. When it gets wet, it expands which makes it difficult to open or close the door.

I am looking for some solution that would be weather resistant.

What type of timber would you recommend to use? Does it need to be treated to make waterproof and what product to use? What paint would you recommend? 

I am afraid that using timber, I will end up in a similar situation several years later and it will rot again.

So, I am wondering if there are some other products I can use instead of timber, for example, stone, tiles, metal, etc.

[JacobZ]

Hi @alex27,

Thank you for your question about replacing a timber sill at your home.

Looking at your image, the timber used on your threshold doesn't look up to the task. Sills need to be sloped so the water will run off and away from the house. Yours appears to be installed level, meaning water will not run off as it should. This, combined with the knots in the timber will allow water to seep into the timber, causing swelling and rot over time.

Timber is fine for use in this application, but the right kind of timber is essential to prevent this swelling and rot. Use hardwoods like Merbau or Blackbutt, as these are more resistant to rot and weather exposure. Protect the timber with oil, varnish or durable exterior paint. 

 There are timber profiles, such as a French sill, that are often made using hardwood and are designed for this specific purpose with the slope cut into the timber. See the below image as an example.

As timber suppliers are often regional, I'd suggest speaking to the team at your local store's Special Orders or Trade Desk about the options available in your area.

As an alternative, composite materials, aluminium thresholds, or stone and tile options are excellent choices as they are highly resistant to rot and moisture. 

For added protection, you might consider installing an awning above the door to stop some of the rain.

Allow me to tag @Nailbag and @Dave-1 to see if they have any advice they can add.

Let me know if you have further questions.

Jacob

[alex27]

Thanks for your response.

I did online search and managed to find timber sills like on the picture you posted. Unfortunately, they come in standard 160mm size (width) which won't work for me. I need around 190 - 200 mm width.

Does Bunnings sell aluminium door thresholds which are wide enough (190 - 200 mm) ?

It may not be clear when looking at my images, but I have two doors in my laundry. One of them is visible on the picture and opens inwards. Other one is a metal security screen door which opens outwards.