Extending Fence Posts

[gord]

Hi all, our new house has a 6~ft fence, but our neighbour's garden must be about 8~ inches higher as it's quite easy to see each other when we're out back unless we're close to the fence our side.

We're looking at options for extending the height by about 18 inches and wondered if anyone had any experience doing this before? The primary criteria are:

• Looks good, the posts are on my neighbour's side and we want the extensions to look relatively seamless, so no metal sleeves, cuffs or plates
• Strong, because wind
• We've got standard vertical feathered panelling, but the extended part will probably be spaced horizontal bars so they won't catch the wind as bad, they'll just be screwed into the fence posts

My initial idea was to drill a 6" corresponding vertical hole in the existing and extending post, probably use a bit of metal bar as a dowel and glue it, much like one of the suggestions here. However, I'm concerned about the accuracy needed for the hole, drilling in line with the existing posts and the extending piece, we could end up with wonky tops if the holes aren't perfect. The alternative feels more extreme, but would be to create half lap joints and use wood dowels so the holes aren't too obvious.

Our builders are pretty reasonable but we haven't approached them yet with this problem. I just doubt it's one they'll take on as there's nothing necessarily wrong with the fence.

Any advice is much appreciated.

 

[gord]

Can't help with how to extend the fence, but be aware you will likely need planning permission for a fence over 2m (approx 6ft 6)

The fence posts are on my neighbour's side, so technically the fence is theirs, therefore the measurement for 2m above ground level should be from their side right? In which case I think we can safely work within that.

Have the neighbours got decking or is the houses on a hill? 8" difference between you and them is a lot.

The hill one. Their entire house probably sits 1.5ft higher than ours.

If you drill slightly oversize holes then you can wiggle them to get them perfectly lined up.
Use some kind of resin to set them in place. It wont be cheap to do.

The height of the fence should be measured from the highest point, so the limit is based on your neighbours higher side
Although its supposed to be based on the natural.

I guess there is the option of attempting perfect holes to start and adapting them as needs to perfect them. Not quite sure on resin though, surely there's something more cost-effective, I mean I was planning on using wood glue. I think we're on the same page as above with regards to the fence height.

Thanks all for the input so far.

 

[gord]

Have you tried speaking to the neighbour first?

Yeh, we've spoken about it. We're planning the approach now so that it looks good from both sides.

Trellis attached to the top?

What did you have in mind? Below is an example of the type of fence we've got. My plan is to extend the main fence posts as described and then spaced horizontal battons up the extended part.

 

[gord]

Are you the feather edge side, or the upright side? I did a similar job for somebody (a mate) who wouldn't entertain the idea of using sleeves or anything - in the end, I used some oak dowel, and cut the extensions at the same angle (don't ask..) which looked pretty seamless from the back when treated. Only drove a few galvanised nails in - friction did the rest - the issue is feather edge warps like billy oh - I doubt you'd get it to match up perfectly. You can buy 300mm / 600mm / 900mm trellis panels which come in set lengths. Assuming your posts are at or around 6 feet? Might be a better job in my (DIY) opinion!

If you're the back side - at least you can reclad the whole thing should you wish - but throw a few climbers up there - you probably won't even notice the join..

We're on the feather side. What size dowel did you use, and just a single centered piece? Did you glue it too?

I'm less worried about the horizontal battons bit, although I am going to mock it up in Photoshop just to make sure it's the right aesthetic. I haven't measured up the fence post distance exactly yet, but I think they're about 3m apart.

 

[gord]

surely a dowel will just snap as soon as any decent wind hits it.

That is why I was considering metal instead of wood for the dowel. If I do go for wood it'd have to be 1" in diameter minimum like Armageus says.

why he keeps walking around in the back garden with his dong hanging out all the time ?

Are you my neighbour? Please stop looking over the fence!

 

[gord]

I used 50mm / 2” oak dowels. 500mm in the base post (mahoosive drill bit extension and an auger bit) and 300mm in the top.

I did use a bit of glue - but friction is happily doing the hard work. And don’t forget the cross pieces too. So far so good!

Awesome, thanks for the details!

Would be worth making a drilling template so that you don't have to measure each one.

There's not that many posts, but I have been doing some research into drilling decent vertical holes..

Trellis would probably be the easiest option. Only other option would be dowels and possibly utilising half lap joints to give a greater surface area for glue.

How would the trellis be attached to the top of a feathered fence?

 

[gord]

With the liberal use of some 2x1 and screws.

I feel like you're not hitting the "must look good" part of the brief. Anything with screws all over the place will irritate me, let alone the neighbours.

 

[gord]

The more I see this post the more I think the correct solution is to replace the posts with new ones.
Especially if its not a particularly new fence.
Higher fence will apply higher load to those posts.

Good opportunity to replace and make sure they are well protected from rot at ground level.

Also decent chance of getting a semi rotted post out whole, rather than the ball ache of a snapped off one

Afraid to say, we're in brand new houses, and the neighbours have just had their garden done so they won't be keen for more disruption. Extending is the way.

 

[gord]

Will the arris rails get in the way if you intend to drill down? How about timbers attached to either side of the posts, notched around the arris rails for more lenght and a stronger fixing. Then attach some trellis to that? It will probably have to be custom made trellis with the bays being 3 metre widths. Or separate posts for the trellis on your neighbours side. Again notched around the rails.

I don't think so, but that is worth checking, cheers. Timber supports either side isn't going to look like a seamless post. The separate post idea is interesting, I hadn't thought of that, but again probably won't be as nice as the extended post option.

If you wanted quicker rather than the drill/dowel method, you can get either universal extension brackets (2 for each post on opposite corners - any size post at least 3 inch), or extension sleeves (to suit 3inch or 4 inch posts). You'd still need to cut your new extension post at a matching angle or cut the top of the existing posts flat however.

https://www.ironmongerydirect.co.uk/browse/gate-fence-and-balustrades/fence-hardware/fence-post-extenders

Afraid those fall into the "no metal sleeves, cuffs or plates" category. I'm not sure I could even use them because I don't think there's a gap between the panels and post.