What’s the point of incised timber?

[NicKarla]

I’m needing to spend several thousands on full fencing around the garden which I intend to make and put up myself. The current fencing put up by the previous owner is around 5 years old and rotten throughout.

Keen to not have this happen again I will be looking for UC4 timber but I can only find it now as incised timber. A few years again I used to be able to buy UC4 grade timber that hadn’t been incised and it was very well done. The timber looks as good now as it did 7 years ago when I bought it. Not sure why there is the change but is incised timber actually a good thing? I suspect its probably just a short cut way of obtaining grade 4 standards, but I could be wrong.

I understand the theory of incising allowing the treatment to penetrate deeper through the cut holes but equally the same cut holes will just lead water directly into the wood rotting it from the inside out, so what is the point? I cant think of anything worse than having channels cut into fence posts. What am I missing?

 

[Notch7]

It's the fence posts which rot the quickest.

If you want them to last longer use post savers - it's a bituminous cover that goes over the end of the post and seals it

The bit that rots is the part at soil level for about a foot down - you could use flashband heat with a heat gun when on and then use a seam roller to get it really tight

Incised timber goes through spiked rollers, it's not at risk of water ingress

The biggest problem with treated timber is that CCA treatments are banned and the chemicals used now aren't that effective.

 

[NicKarla]

Why is the wood not at risk of water ingress? There are cuts in the wood, that’s how the treatment gets deeper into the wood. Why would water not do the same.

 

[scbk]

What type of fencing are you wanting to put up? You can get various types of materials - steel (plain or galvanised), concrete, different species of timber; spruce, larch, oak, chestnut, creosote treated, etc

 

[NicKarla]

Erm, I’m wanting to put up UC4 timber fencing but am put off by the incising. Just trying to make sense of the use of incising which seems counterproductive to me.
Im trying not to get side tracked by other questions other than to say that the materials listed above are either ugly, impractical, or just too expensive.

 

[scbk]

It's barely more than a scratch, look at the wooden "hydro poles", the guys climb up them in spikes which takes big chunks out of them.

 

[Why Not Indeed]

The question stands; if the incisions allow the treatment to penetrate, then they also allow the weather to penetrate. Does the treatment perhaps seal the incisions?
Having said that, if everybody is doing it then there's probably a reason and it's probably not just a gimmick.
At the end of the day, if you insist on leaving dead wood outside in contact with the ground, then you have to expect it to eventually rot. Either you factor that in to the cost of owning a fence, or you adjust your plans [eg concrete spurs in the ground, timber posts bolted to them].

 

[johnny2007]

We used to dip the lower part of fence posts in exhausted engine oil and leave them for half hour or more if possible.
It leaves an unsightly black mark at ground level and a few inches above, but it resists rotting a lot better.

 

[Notch7]

Why is the wood not at risk of water ingress? There are cuts in the wood, that’s how the treatment gets deeper into the wood. Why would water not do the same.

timber doesnt rot by water penetration into the surface - so incising has no effect.

timber rots due to water traps, where the water sits, like at soil level, or at joints

If you hung a piece of untreated softwood outside, just dangling vertically, it wouldn’t rot for many years because after each rain, it would dry quickly.


I think you are focused on the wrong issue

 

[Fred Blogs]

I used some incised timber a while back. It doesn't look very pretty to be honest. I ended up running it through my thicknesser and recoating with shed preservative.

 

[Why Not Indeed]

timber doesnt rot by water penetration into the surface - so incising has no effect.

Kind of obvious now you've said it!

 

[Deluks]

I am in agreement with the OP, there doesn't seem to be a need for it and is probably just another silly sales gimmick, like bright blue roofing battens!

Maybe it helps reduce the pressure required to get the preservative to the required depth? So possible energy savings to be had?

Looks crap though.

 

[NicKarla]

Either you factor that in to the cost of owning a fence, or you adjust your plans [eg concrete spurs in the ground, timber posts bolted to them].

Ideally I would use concrete spurs/Godfathers but no one seems to sell them in West/North Yorkshire area or if they do they are £20-£25 which is absurd.

I appreciate the comments about water rotting from water traps but surely incision would lead to the water being trapped more. Channeling water into the middle where it has nowhere to go.