Thread: How to fix T&G jarrah externally?

The boards themselves, in the pattern you propose, can provide diagonal bracing. I'd attach all of them to the outside frame, two screws for each end of each board. Expansion is only across the grain, not along. If you set the boards with the tongues upwards, you can leave a slight gap for transverse expansion, and they'll shed water. In fact, for exterior use, tongues upwards is best for any condition.

I'd still use glue, but only on the exposed end grain.

Cheers,
Joe

Whats the size of each door?
How are the doors going to be hinged? and to what?
Being for a carport/garage the doors would be a fair size and cladding with solid timber is going to be a lot of weight.

How about some photos

Cheers
Rod

Each door is about 2.5m wide by 2.2m high. I've worked out the weight of the steel and the jarrah, and even erring very much on the side of caution then each door comes in at under 200kg (actually nearer 130kg). I'm using hinges with thrust bearings from this range - Hinges with bearing
I've gone with the hinges which can support 400kg. The bottom is well and truly fixed in the ground and the top is bolted to an RSJ in the roof. How do you spell "over-engineered" again?

No photos as yet, but here's a rough sketch of what the frame looks like -

Attachment 186482

The black blobs are the hinges and the small diagonals are actually evenly spaced at about 60cm. These are what I'm planning on fixing the boards to, tongue upwards, same as Joe's suggestion and parallel to the main diagonal.

I'm leaning towards fixing alternate boards with two screws in each diagonal it crosses with light weight flat bar across the otherwise unsecured ends (joined to each other, but not to the frame, to allow for some expansion movement).

I pushed the boards together this evening and secured them temporarily with the strapping that's used for timber frame houses. This will allow me to cut the panel to size tomorrow night (if I get home before dark). Then comes the fun bit of lifting the whole bloody lot into place! Both my neighbours who usually lend a hand are away on the mines for the next couple of weeks, so it looks like my wife is going to be pressed into action as a labourer. Should be fun.


Graeme

Your "main diagonal," if constructed as shown, is in compression and subject to buckling, which limits its capacity. Tension members utilize full strength, so it would be more effective if run from the upper left to the lower right. The smaller diagonals in that direction are then substantially "passengers."

Since the door will sag with either orientation, a turnbuckle in tension would allow adjustment to level. The boards, in chevron array, provide additional stiffness in compression, hence my suggestion to connect all boards at both ends. It will be beneficial to prop the end of the door while attaching the boards, adjusting the turnbuckle as work proceeds.

There will be less heavy lifting if you pre-assemble on the ground, without screws, to cut the boards; match-mark the boards and remove; hoist the frame, and do the final assembly in place. If the boards are not full length, the smaller diagonals mentioned above can provide intermediate attachments, and be more than just "passengers." The board joints should then be staggered like brickwork.

Cheers,
Joe

Originally Posted by joe greiner

Your "main diagonal," if constructed as shown, is in compression and subject to buckling, which limits its capacity. Tension members utilize full strength, so it would be more effective if run from the upper left to the lower right. The smaller diagonals in that direction are then substantially "passengers."

Buckling was one of my concerns so it was one of the things I tested when I first put the frame up. Primarily to test the hinges I put a couple of hundred kilos on the opposite end of the frame (in the form of myself and a neighbour) and everything seemed pretty solid with no noticable deflection of any braces. As the weight of the wood itself is well under 200kg and is evenly distributed rather than a point load I'm pretty confident that it'll cope. All the braces are square or rectangular section steel tubing and robustly welded at all joints (tested with a good whack from a 2lb hammer) so they should handle at least some compression without too much deflection. I'll definitely keep in mind the turnbuckle idea though, just in case.

Originally Posted by joe greiner

There will be less heavy lifting if you pre-assemble on the ground, without screws, to cut the boards; match-mark the boards and remove; hoist the frame, and do the final assembly in place. If the boards are not full length, the smaller diagonals mentioned above can provide intermediate attachments, and be more than just "passengers." The board joints should then be staggered like brickwork.

I cut boards for one of the doors last night and it dawned on me then that it would be easier to lift the frame then the panel, though it will require temporary bracing of the panel (so I don't break the t&g). Fitting one board at a time won't work as the panel is recessed and I'll be working from the centre board outwards. I've managed to get boards that run the whole length, so there's no need to stagger them (there was a lot of wastage due to broken t&g, gouges etc., but I've plenty of it and it was free).

It's been bucketing with rain for the last couple of days in Perth and the panel is uncovered, so I'm slightly less concerned about not leaving enough room for expansion as it will have expanded to pretty much its maximum.

Graeme

Joe is right; having the diagonals run the other way is better construction technique.

As he also mentioned, there's more expansion across the grain than along!

So, by the time the weight eventually settles onto the diagonals as bracing - and it will. Eventually... - your boards will no longer be at the same expansion as at build time.

Most likely the door will sag slightly, if they're already at 'maximum' mc.

Of course, you could always simply put an extra diagonal cross-member in place in t'other direction instead.... or the turn-buckle. But better to avoid the whole issue in the first place, y'know?

Joe and Skew are right. Metal bracing should be in tension. Timber bracing is usually in compression.

G'day Graeme.
How thick are your boards? I understand you want to screw through the frame into the timber to end up with a smooth surface. The problem I see is the screws losing their grip in the timber over time specially being in jarrah.
If this was my project I'd be screwing through the timber into the frame. I'd make a feature of the screw heads by using hex head teks or coach bolts with nuts on the frame side, making sure they are all neatly lined up.
Before the roller/tilter door became common most garage doors were made of timber as you propose, and if the timber is securely attached to the frame then it's irrelevant whether it's in compression or tension.
After you finish paint (or mop) the timber with cabots deck oil.

Regards,
Geoff.

Originally Posted by Boringgeoff

G'day Graeme.
How thick are your boards? I understand you want to screw through the frame into the timber to end up with a smooth surface. The problem I see is the screws losing their grip in the timber over time specially being in jarrah.
If this was my project I'd be screwing through the timber into the frame. I'd make a feature of the screw heads by using hex head teks or coach bolts with nuts on the frame side, making sure they are all neatly lined up.

The boards have been planed to 20mm thick (a nice quick job with my new planer/thicknesser toy). They started about 22mm but some had a fair bit of damage after 40 years of foot traffic (some of which may have been footy boot studs). The screws go 15mm in. I did wonder about whether or not they'd hold up long term and the thought of coach bolts did cross my mind. I prefer the cleaner look of screws from the back so I'll go that way to start with but be ready to swap to coach bolts if needed after it's been up a while.

I was hoping to get the first door finished this weekend but I've been a bit crook (only ever happens at the weekend or when I'm on holiday! I must be allergic to relaxation). Cabots deck oil sounds the way to go, particularly mopping it on


Graeme