Thread: Hardwood fence - Horizontal slats - Jarrah?

I assume the screen is outside?
If so then as long as you don't expect any wood to retain its natural colour for more than a few months you should be OK.
No matter what you do to it unless you are prepared to sand and reseal it every year it will go grey and in between this it will look tatty.
If you don't like grey you might as well paint it straight up as it will provide the best long term protection for the wood.

In terms of spacing I would recommend posts closer than 1.5m otherwise the boards in a horizontal orientation will eventually sag and twist even though the timber is on its edge.
Maybe something like 750 mm.
If you make it with green timber it will shrink and develop a gap.
If you make it with dry timber it will swell when exposed to rail and it may pop some of the boards off.
If you want to reduce the impact of gaps on privacy then a double panel walled with gaps on both sides will work but of course is more $.
The other alternative is a weather board look, overlapping boards - This would look good using something like cedar (panted of course cladding

Hi BobL,
Yes, the screen is outside.

I knew that the wood would eventually go grey if not maintained, but I didn't think it was a dire as you're predicting. Does this happen with decks as well? I thought a clean and re-seal once a year would be enough. Do people with hardwood decks really sand it every year?

As far as spacing goes, will 1.5m posts with a vertical 'runner' (sorry, forgot the name) in the middle, but not anchored, achieve the same support structure as posts every 750mm? Trying to avoid drilling into the concrete too much.

If I use dry timber, what do you think is the smallest gap I could do without a big risk of a board popping off after swelling in the rain? Will coating it with a good deck sealer reduce the risk of swelling?

I'm starting to think maybe I should just do a colorbond fence. At least I won't have to worry about maintenance, but I'd much prefer the look of a nice hardwood fence.

Why don't you just erect a 6' lapped and capped hardwood fence? Posts can be bolted or you can core drill the concrete. The lapped fence allows for movement of the palings and provides a continuous barrier (no gaps). You can paint, stain/oil or leave raw. Raw will turn grey after a few months.

paling04.jpg

Originally Posted by silentC

Why don't you just erect a 6' lapped and capped hardwood fence?
paling04.jpg

I'm just not sure I like the look of the lapped and capped fence. If it was for a boundary fence on the perimeter of the block then I'd probably go for something like this. But it's basically for a divider between 2 houses on a subdivided block, on polished concrete, and within 1 metre or so of living areas. I guess it needs to be more of a 'feature' fence.

I'm picturing something like this (the merbau part, not the brushwood): merbau-decking-fence.jpg

I appreciate all the tips and options.

You said you were starting to think about Colorbond, I think lapped and capped hardwood is a step up from that

Anyway, to answer your original questions:

1. Merbau does leach a bit, I don't know about Jarrah. You can avoid it to a certain extent by weathering it for a bit before using it, or there is a product you can use to help get rid of the excess tannins. Decking boards are fine, but try to get it without the grooves on one face if you can because it will be visible from one side of the fence.

2. You need a gap but it only needs to be a few mm at most. Decking is usually laid with a 3 or 4mm gap which opens up a bit as the boards dry. If it is wet when you buy it, you can lay it with a minimal gap. If it is kiln dried, you would lay it with a 5mm gap or thereabouts to allow for expansion.

3. Wider boards are usually thicker and more expensive per sq. metre. If you use wider boards in the 19mm thickness they are more likely to cup noticeably. Narrow boards will do this too but it's less obvious.

4. 1.5 spacing is borderline I reckon. It's OK for a normal hardwood fence with vertical panels but you will not have the heavier rails to hold it all straight. The closer the posts, the less wobble you will get as the boards move. 19mm decking is usually fixed at 450mm centres, mainly for load bearing but it also helps keep it straight. The picture you show has the boards held at the ends. You might get away with it but it could also look crap in a few years. People take photos like that the day they apply the finish to the fence. What does it look like 5 years later? If you use 19mm decking it will certainly bow.

You won't get away with staining it pre-assembly and then touching it up. It will need to be redone every year or two if you want it to stay looking like the photo.

If you want the no maintenance, retain its colour thing, themn you can get the powdercoated wood look aluminium 'boards' from bunnies and other places. They won't twist in the sun or anything either.

There's also Modwood, which is basically a composite material made from recycled plastic and wood fibre. It has a permanent finish.

http://www.modwood.com.au/screening/

Originally Posted by silentC

You said you were starting to think about Colorbond, I think lapped and capped hardwood is a step up from that

Agreed, however is it enough of a step up to justify the extra maintenance? That's what I'm not sure of.

Originally Posted by silentC

3. Wider boards are usually thicker and more expensive per sq. metre. If you use wider boards in the 19mm thickness they are more likely to cup noticeably. Narrow boards will do this too but it's less obvious.

Thanks. This is what I'm after. I don't know what cupping is, but now that I know what to look for I can look into it. I prefer the look of the wider boards, but if cupping is an issue then I'll consider the 70 or 90mm boards.

Originally Posted by silentC

4. 1.5 spacing is borderline I reckon. It's OK for a normal hardwood fence with vertical panels but you will not have the heavier rails to hold it all straight. The closer the posts, the less wobble you will get as the boards move. 19mm decking is usually fixed at 450mm centres, mainly for load bearing but it also helps keep it straight. The picture you show has the boards held at the ends. You might get away with it but it could also look crap in a few years.

I'm thinking of 1.5m between posts with a dropper in the middle (so 750mm between supports). I could add 2 droppers between the anchored posts to make it 500mm between. Is that advisable?

Originally Posted by silentC

People take photos like that the day they apply the finish to the fence. What does it look like 5 years later? If you use 19mm decking it will certainly bow.

Yeah, that's why I'm having so much trouble with this. Obviously any googling I do about this sort of fence shows it the day it was installed. I'm having a hard time picturing what it will look like in a few years time. That's another in the much smaller bucket of pro's for the Colorbond fence.

Originally Posted by silentC

You won't get away with staining it pre-assembly and then touching it up. It will need to be redone every year or two if you want it to stay looking like the photo.

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I know it will need to be redone every year or so, but is there another reason why you say I won't get away with pre-staining it? I just think it will be a little easier initially than doing it once it's erected.

Cupping is where the board curves across it's width, so it forms a cup shape in cross section. It depends on where it has come from in the tree and how it has been dried as to how likely it is. I'm looking out my window now at some 90mm Merbau decking and none of it is cupped but I have some 200mm x 30mm blackbutt which I used for a handrail and it is cupped slightly. The decking that is exposed to the weather is more likely to cup also.

I didn't mean you won't be able to pre-stain it. I misunderstood what you meant about touching up after erecting the fence. You meant immediately afterwards, I was thinking you thought you could do it thoroughly once and then just touch up for maintenance down the track. The whole thing will have to be redone every so often - if you want it to keep looking new. I used merbau for my deck and I've oiled it 3 times in 8 years. It needs doing again. More fussy people would do it once a year, but I don't mind it looking a bit weathered. I used an oil based deck finish with a merbau stain. The stain helps make the colour more consistent and the finish lasts longer than a clear finish because the pigment protects it a bit more from UV.

The droppers will help keep the boards equidistant along their length. It will probably help reduce individual boards bowing too. But if they are not connected to something solid, either the ground or a solid rail, the whole thing can sag in the middle.

What I like to do is to see if I can find an actual example that can be examined up close and see how they've solved the problems. If you can find someone in your area who has done something similar, take the dog for a walk and have a sticky beak.

Originally Posted by silentC

Cupping is where the board curves across it's width.....

Thanks for all the info silentC. I'm feeling positive about it now. Staining every 1 - 2 years sounds ok to me.

Ok, so I've planned out what I want to do, and just want to run it past someone for any obvious issues

1. There will be 5 Cypress posts, 1.4m from center to center. We're going to cut a 10" hole in the existing slab, dig down to 600mm, seal the bottom 600mm of the post with an inground sealer (i.e. http://www.bunnings.com.au/timber-pr...p0106_p0960008), and cement in. Posts will be about 2m above ground (with a pointed tip). I'm planning to use either 100x100 or 115x115. At each end of the fence, the boards will overhang the posts by about a foot, to avoid cutting/digging etc. right against walls.

2. There will be vertical droppers halfway between each post. These will essentially be floating, not fixed to anything. I am a little worried about sagging. How much would it help having another cypress post running horizontal at the top or bottom? I'm hoping to avoid this if I can, as I'd prefer to look at just jarrah, but unfortunately the most visible side (to me) will be the rear side..

3. I'll be using 130 x 20 or 140 x 19 Jarrah boards (depending on which supplier I can get it from in fixed lengths). I'm hoping to get 3m long boards so that they span 2 posts. They will be spaced 5mm apart, with a 50mm gap at the bottom (I haven't done the exact math for height and length yet). I'm not planning on capping (unless the advice from the question above changes my mind). Are there benefits to capping, besides aesthetics and potentially avoiding sagging issues? e.g. does the top board weather worse if the side grain is exposed?

4. I'm thinking that if I decide that I don't like looking at the rear side of the fence, with it's posts and droppers visible, I could add more decking boards to the back of the fence later on, so it's double sided. My only concern is then only being able to maintain (clean, seal etc.) one side of the boards. Is this a valid concern?

5. One of the sections (1.4m wide) will be a gate. We'll be making a Z frame from cypress posts. Hinges will be on the front side, so that the gate swings outwards, not inwards.

6. Boards will be scrubbed with a napisan solution, dried, and oiled before going on. I'm thinking Cabot's AquaDeck. Is this reasonably durable? Is there another that would last a lot longer? Am I correct in assuming that a water based stain will be easier to get any spills etc. off concrete than an oil based stain?


Thanks to anyone that can comment on one or more of my points.

I was looking at this one last Tuesday:

top-pub-pambula-deck.jpg

I think the spans are similar to what you're proposing, maybe closer to 1.8, but they have used thicker boards, looks like 140 x 30mm decking. They have milled a groove in the side of the posts and dropped the boards in. There is a 10mm gap between each. Some of the boards have bowed and the gaps are inconsistent. The side you can see in the photo faces south and it's not as bad as the west-facing side which you can't see (to the right in the photo). But sagging appears not to have been an issue, probably because of the heavier boards.

I cant say if they will sag. My gut-feel is not much and I'd probably be happy enough with those spans, but then my tolerance for things like that might be higher than yours

Capping protects the end grain of palings, it is not structural usually. You don't have any exposed end grain, so it would be purely aesthetic in your situation. I think it would probably detract from the look you are trying to achieve.

Personally I wouldn't worry about adding more boards to the inside of the fence. I think you will get used to it.

I've only ever used oil-based stain. Can't tell you anything about the water-based stuff. I don't think there would be much difference in the clean up of splashes though because if you buy one with a stain in it (recommended) it will discolour your concrete no matter what I think.

I always get it with a stain because it will even up the colour variation in the boards and it protects the finish from UV longer, so you get more life out of it. The only downside is that it looks a bit ordinary if you let it go because the stain will wear away in places and not in others. But you won't let your fence go as long as I've let my decks go, will you?

Using 19 mm at 1.4m spacing I reckon they will eventually sag.
Think about what would happen to standard weather boards at that spacing?
There is a reason that 600 mm spacing is used for weatherboards

I would avoid the water based stain. It is more like paint so a real pain to maintain later on. I did my barbie table with it and now wish I had not done it. Going to have to sand it right back now. The real advantage of oil based deck oil is how eazy it is to tuch up scratches and things later on. A year down the track it is scrub then wipe over with the oil again.
Regards
John