What to treat fence posts with

firsttimebuyer2013

I'm going to be sinking some 10x10 fence posts in concrete for my decking supports. The problem is, I don't know what to use to treat them to prevent, or delay, rotting.

I'm quite new to the garden and was planning on using creosote like my dad used to. Seems I'm about a decade too late for that.

Davesnave

These days people don't treat the post to stop rot, they buy posts pressure treated so that the inside has protection as well as the thin layer on the outside.

Treatments vary, but the best, the Jakure process from Jacksons fencing, is guaranteed 25 years. I have field fencing which is guaranteed not to rot for 15 years, or they replace them. An average low quality fencing stake can rot at ground level inside 5 years, as some of my tree stakes have already proved.

I believe one of the main rot-proofing processes used on softwood is Tanalith E, but my experience is not with decking timbers, I'm afraid.

elaineruk

I found an article here on goto4gardening.co.uk/how-to-put-up-a-garden-fence
says most come treated as standard. I remember helping my dad to creosote his fence too :-)

glasgowdan

Make sure the bottom of the fence post isn't totally surrounded by concrete, i.e. it should stick out below the bottom of the concrete base. This stops water pooling around the post as much.

But yes, fence posts aren't usually given an extra treatment now.

pogg000

many years ago a gardener i knew used to dip them in use engine oil and swore by it as they lasted for years

wrightk

as dave has said posts are pressure treated nowadays. Part of the pressure treating process is squeezing a chemical called tanalith into the wood to prevent rot.
You shouldn't HAVE to treat them as they will go from a freshly treated greeny brown to a golden orange colour then eventually grey when they are reaching the end of their life. If your trimming posts or exposing any edges brush on some end grain preservative. Many people just decide to paint them anyway which isnt a problem either

The weakest part of the post when up is the base where it meets the ground. Make sure the water doesn't pool around the base of the post or this will accelerate the rotting process.

There are other options such as met post post protectors (essentially just a metal jacket that sits around the post around the base some of it is in the postcrete and some will be protecting the base at the soil level. I've never tried these before so cant vouch for their effectiveness over a long period. Worth a look out though