How to fix rotten timber beams on pergola?

Nanne

Looking for some advice on repairing these exterior timber beams.

I know the lichen needs to be removed/killed first. Once the timber is cleaned and completely dry, I’m hoping to rebuild/repair the damaged sections rather than having to cut them out or replace the beams.

What would be the best product and method to repair them — wood hardener followed by a two-part epoxy timber repair filler, or something else?

JacobZ

Hi @Nanne,

The photos are a bit difficult to see. Is it possible to get some higher resolution photos showing the damage?

It looks like they are just the rafter tails which have been cut into a decorative taper. As long as the damage is only to the tips, which aren't supporting a load, then it should be fine to repair them, however if the damage extends further inwards towards the beams, then I'd be more inclined to say things need to be replaced. If the damage extends further inwards, then I'd suggest you need to have it inspected by a suitably licenced person such as a carpenter or licenced builder to ensure there is no structural risk.

If you can confirm there is no structural risk, you'll want to start by removing as much of the rotted timber as possible, then coating the inside of the removed section with https://www.bunnings.com.au/earl-s-1l-wood-hardener_p1585291 . It will help to stiffen up slightly rot effected timber, but it won't fix the really bad stuff.

Once the rot has been removed and the hardener applied, fill the void with https://www.bunnings.com.au/turbo-500ml-builder-s-bog_p1212026 , allow it to dry, give it a sand, then prime and paint.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob