Use bitumen / preservative or nothing on a post

[kiteman69]

There are many topics on how best to protect a wooden pressure treated post, that is going into concrete
1) Coat the bit in the ground in bitumen
2) Coat the bit in the ground in preservative (i.e. cuprinol)
3) wrap it in blue builders plastic
4) do nothing as the pressure treated stuff is better protected than a DIYer can do
5) don't stick it in the ground at all, but mount it in a metal boot (but that looks an expensice option)

My idea is to get several 4 foot posts and cut them in 2 (putting the treated end in the concrete (sloped away from the post) and painting the new top end with a preservative

What are your views.

And what is the preservative of choice

 

[Thermo]

pressure treated doesnt need anything else, ask the manufacturers. weve pulled stuff out of the ground thats been there years and you would think its virtually new

 

[kiteman69]

Thanks for clearing that up Thermo

 

[Deluks]

pressure treated doesnt need anything else, ask the manufacturers. weve pulled stuff out of the ground thats been there years and you would think its virtually new

Depends on the ground conditions, I've dug out rotters that had only been in 4 years!

I'll always give it an extra soaking in something, also good (but fussy) practice that the concrete should be haunched up around the post slightly above ground level. Dashed with shingle it doesn't notice as much.

Full concrete coverage also better than chucking in loads of hardcore and skimping on the concrete.

Of course John will be along shortly with his view on the matter!




Dug out rotters, ooh that sounds v.dirty.

 

[LeadFarmer]

Im not a professional, but Ive always coated the bottom of my wooden posts with creosote substitute, or similar. Once its in the ground you wont get another chance.

Im not a very trusting bloke, and I therefore assume that some timbers might not have been pressure treated properly, especially if the suppliers have cut corners/costs etc.

 

[kiteman69]

Thanks LeadFarmer, How long does Bitumen take to go off, or doesn't it.

I.e. do I paint the bottom of the posts, and then just set them in the hole, or do i have to leave it 24 hours (perhaps even gving them another coat)

I have just phoned my merchant and he says it is £8 for 5 litres, is that stuff you would use. (Do you also have to heat it up before using it)

He just recommended coating them in a designated end grain preserver

 

[Deluks]

Thanks LeadFarmer, How long does Bitumen take to go off, or doesn't it.

I have just phoned my merchant and he says it is £8 for 5 litres, is that stuff you would use. (Do you also have to heat it up before using it)

He just recommended coating them in a designated end grain preserver

I'd go with the creo substitute or proper end grain preservative as suggested. Bitumen is sold in blocks and needs heating up to melt it: messy, smelly, very hot. Sold in tins would be bitumen paint, more for concrete surfaces and metal than timber.
But full concrete coverage will keep the post encased and protected from ground moisture. Keep the mix stiff, too much water can lead to the concrete shrinking back around the post, increasing the chance of moisture ingress.

 

[LeadFarmer]

Thanks LeadFarmer, How long does Bitumen take to go off, or doesn't it.

I.e. do I paint the bottom of the posts, and then just set them in the hole, or do i have to leave it 24 hours (perhaps even gving them another coat)

I have just phoned my merchant and he says it is £8 for 5 litres, is that stuff you would use. (Do you also have to heat it up before using it)

He just recommended coating them in a designated end grain preserver

I would just use Creosote Substitute (I think the original Creosote has been banned) or a wood preserver from DIY store. It will soak into the wood. Bitumen I guess will just cover the outside of the post.

Creosote turns wood a very dark almost black colour, so Ive just put it on the bottom section of the post that will be in contact with the soil. Then stain the visible part of the post to a more acceptable colour.

 

[JohnD]

If you use concrete posts and gravel boards they will not rot so that's another problem solved.

As the lads on here all know, you can paint concrete posts with masonry paint to make them blend in with the wood-stained fence. I can show you a photo if you like.