Cutting fence panel from bottom - will wood rot

Elmroad82

Hi,

I have about 5 close board fence panels that are too high. They’re only 2 years old and were pre stained and treated when I bought them. The rear of the panel has horizontal battens to give it strength every 1.5ft(ish) up the panel. I plan to cut below the bottom batten (see red section in image), then put back into position thus lowering the fence. Are the vertical pieces of wood/slats, stained and protected all the way through the wood or will they start to rot as cutting them will expose the untreated middle? Thanks 

ThisIsWeird

Treatment only penetrates a tiny amount, and you'll likely see this when you cut through - the brown stain will barely be 1mm.
So, yes, it'll need redoing along the cut end, especially so as that's where water collects before dripping off - it'll always be the wettest edge of the boards.
Do the very tops of these boards have flat timber strips to cover them? If so, an alternative solution could be to cut off the top section instead, and then replace the protective top strips. But they'd still need treatment first!

Not sure what the best stain-preserver is, but it definitely needs to have 'preservative', and then a means of repelling water. 'Creocote', for example, will only do the latter - it doesn't 'preserve' against rot (unlike the original 'Creosote').

Elmroad82

Hmmm, The tops of the boards have a strip so they need to be cut from the bottom. How about roofix? It’s like a thick  treacle with bits of small fibreglass I think for repairing roofs. I’ve got some in the shed..
“Roofix 20/10 can be used to repair specific areas that are leaking or totally waterproof an entire roof.
This product is multi-purpose and can be utilised on a wide variety of problem areas.
A single pack elastomeric acrylic based (non bitumastic) compound, with built in draylon fibre reinforcement, providing excellent flexibility and durability.”

https://www.paints4trade.com/flag-roofix-2010-waterproof-coating-black-paint-5-litre-265597-p.asp?_=&variantid=265599&gad_source=1&gclid=Cj0KCQiAire5BhCNARIsAM53K1iSjL7EhToNez1gJKOoONbxjXrM_aOMQLYilpMB06hQiagn0LBydHQaAokGEALw_wcB

gwynlas

Rather than place cut edges directly on the ground where they will wick up water you could rest them on gravel boards. If you do not have the means to install gravel boards then lengths of tamilised timer would help or even just a row of bricks.

Elmroad82

Fortunately they’re on wood gravel boards. 

ThisIsWeird

Elmroad82 said:

Hmmm, The tops of the boards have a strip so they need to be cut from the bottom. How about roofix? It’s like a thick  treacle with bits of small fibreglass I think for repairing roofs. I’ve got some in the shed..
“Roofix 20/10 can be used to repair specific areas that are leaking or totally waterproof an entire roof.
This product is multi-purpose and can be utilised on a wide variety of problem areas.
A single pack elastomeric acrylic based (non bitumastic) compound, with built in draylon fibre reinforcement, providing excellent flexibility and durability.”

https://www.paints4trade.com/flag-roofix-2010-waterproof-coating-black-paint-5-litre-265597-p.asp?_=&variantid=265599&gad_source=1&gclid=Cj0KCQiAire5BhCNARIsAM53K1iSjL7EhToNez1gJKOoONbxjXrM_aOMQLYilpMB06hQiagn0LBydHQaAokGEALw_wcB

These are decent quality panels, and should last decades if looked after. Two ways to do this - one is to 'preserve' the timber so that it prevents it from rotting, and the other is to try and prevent water getting to it in the first place using a paint or coating.
The latter rarely succeeds. 
So I would always recommend a good preservative first.
You can get dual purpose types that will also repel water, but I'm not sure which ones are best these days.
Your roofing product is good stuff, and would likely work well if applied to the tops of the panels to shrug off rain. But you will almost certainly find, if applied to the bottoms, that rainwater travelling down the boards, and wetting its surface, will find a way in under the coating on the bottom. Once it does this, it'll make your boards rot more quickly, as this water will now be trapped under that coating, and the timber almost permanently damp.
I'll have a look to see what the best products currently are, unless folk on here know?
You ideally want a 'staining preserving water-repellant'.

km1500

this might help

https://www.avsfencing.co.uk/blog/uc4-timber-preserving-treatment

FreeBear

Elmroad82 said: Hmmm, The tops of the boards have a strip so they need to be cut from the bottom.

The capping strip will be nailed in place. Careful use of a pinch bar should get it off with no real damage. It can then be nailed back in place once the panel is cut down to size. That said, attacking it from the bottom saves hassle, so that is probably what I would do. And then treat the cut edges with a simple preservative - I've used the No-Nonsense stuff from Screwfix, and the sheds I painted don't have any signs of rot some 6-8 years on.

Belenus

Consider buying 5 new panels of the correct size and selling your own 5 panels to recoup some of the cost?

That might save you the time and effort of resizing your existing panels and give you a more satisfactory end result.

casper_gutman

FreeBear said:

Elmroad82 said: Hmmm, The tops of the boards have a strip so they need to be cut from the bottom.

The capping strip will be nailed in place. Careful use of a pinch bar should get it off with no real damage. It can then be nailed back in place once the panel is cut down to size. That said, attacking it from the bottom saves hassle, so that is probably what I would do. And then treat the cut edges with a simple preservative - I've used the No-Nonsense stuff from Screwfix, and the sheds I painted don't have any signs of rot some 6-8 years on.

I've also used the No-Nonsense preserver to satisfactory effect. It's quite low viscosity, which seems bad at first, but when you slop plenty on it soaks into rough sawn timber very well.

In the past I've used it on cut ends of timber by standing them in a tub of preserver and leaving them to soak it up for a while, rather than trying to brush it on. That might be tricky to achieve with a whole fence panel, but gives an idea of the effect you're going for!

They do clear and tinted versions. I'd look for the clear version for cut ends as the tinted stuff wicking up the strips of wood will change the finished colour on the faces of the timber near the cut.

Elmroad82

Thanks all… Would old engine oil do the trick? I’ve got 5L that needs disposing off…