Damp rot in doorpost - should I let it breath or seal it up.

[Silvan]

Hi folks,

I have been having a problem with dampness in a front doorpost. Every couple of years I was finding some rot at the bottom of the post, digging it out, filling it, then painting over it. I assume that some dampness was getting in at the top then ending up at the bottom due to gravity. At the bottom it had nowhere to go so rotted the wood. About two years ago when repainting I filled the damage as normal but left a section at the bottom open to the air. This seems to have worked in that no more rot has occurred.

I'm going to be sanding back the doorpost and repainting it. Is it a good idea to leave a section of it unpainted? Or maybe there is a breathable paint I can use? Or some kind of wood treatment like couprinol? I'm not too fussy about how it looks, I'd be happy to do the west-facing bits with regular gloss paint and give the north-facing part of the door-post a different colour (or plain wood with some couprinol-type treatment). The door faces west, so the untreated section in the picture faces north and gets very little rain or sunshine.

 

[Scally-Ho]

Ever thought about replacing the wooden support with aluminum box section?

 

[Silvan]

At the present time am just thinking to keep repairing. Sometime in the future new door, windows, post. And probably roof as it is a bit crap too. But for the mean time a repair and paint.

 

[opps]

The water ingress may be down to the fact that the putty at the bottom seems to have a large gap.

You could use caulk to fill the gap, a MS polymer such as CT1 would be better.

You can use cuprinol as a primer, but, from memory it needs a week to dry before over painting (if using the oil based Dulux Trade Weathershield (oil based).

Which filler have you used? I can't tell from the photo. Often fillers expand and contract at a different rate to the timber. Ideally one would use an epoxy resin filler, alternatively cut out the rotten timber and splice in a new bit of timber)

They are expensive but the following is incredibly good value (comparatively). I have used the other two market leaders but the following is every bit as good, and a LOT cheaper.

Rebuild Epoxy Woodfiller | Oxera Repair Products

Our extensive range of expoxy resin products can save the existing unit, saving the customer huge some of money whilst also minimising the impact on the environment, as often just 5% of the timber is affected, making it hugely wasteful to replace the whole unit.

www.oxerarepair.co.uk

You may need to hack away more of the rotten timber (and let it dry). Tetrosyl wood hardener may help.

 

[Silvan]

Thank you. I have used a variety of fillers over the years, and Ronseal Wet Rot Wood Hardener.

The post is completely dry now and it isn't rotten, though it may need a touch of filler here and there. The present state of play is in the photos below.

 

[opps]

I looks light you may to remove a bit more timber- some bits are very dark. Difficult to tell from the photo. If you run a flat head screwdriver over the darkened timber, is it still soft?

I have never used the Ronseal product. I used to use expensive 2 part wood hardeners. I didn't have problem with the cost, but sometimes they would (occasionally) stay tacky for days. @jobandknock recommended the Tetrosyl product, it is one part but you need to clean the brushes with cellulose thinners. The 2 part epoxy- you have to bin the brush after.

Edit- in the event that the filler is going expand/contract. It might be prudent to prime/paint the timber before using more filler.