Thread: Building Jarrah Timber Deck - Need Some Advise

Deucer

Mate, sounds like a nice deck. I wish we could get jarrah over here for a decent price.

The bend in the boards shouldn't be too hard to sort out. I always start at the outside of the deck and work towards the house - that way if you have to cut a board, it is hidden hard up against the house and you can't really see it. A board cut along its length on the outside of a deck could look terrible.

Choose straight boards for the first few rows. Then you can use the bent boards. Depending where the bend is in the board and which side you want to use, I usually just bang in the nails for the first few joists (definitely more than one joist). Then I use a big quick grip clamp and use the clamp to bend the board back to square. Progressively nail for each joist. Too easy. Depending on the amount of bend, you might need to clamp it halfway along first and then clamp at the end. If you go straight to the end, the gap in the middle can close up.

It is a bit harder when you get away from the first few boards as the gap between isn't big enough for the clamp to fit in. I used to do it on the ends of the boards then, because the ends were all different lengths and there was usually one sticking out far enough to find something to clamp. Otherwise get a mate to hold it while you secure the board.

As for other hints, definitely oil both sides before you lay it. Well, thats what I did anyway. The in-laws have to be good for something!

Leave the ends of the baords overhanging the edge until the end then run along with a circular saw to neaten it up.

drill before you nail on hardwoods

make up a jig so that all your nails line up nice and straight and they are all in the right place on the board. It looks really bad when you have wavy lines for your nails. A jig will take you 15 mins and it will make life soooo much easier.

Good luck

let us know how it goes.

Trav

Hi Trav,
Thanks for your reply.... t'was really helpful!

I'm from QLD originally so I'm making the most of the opportunity to get jarrah while in WA. It's becomming more difficult and expensive to come by over here too.

Thanks for the tip re: straightening the boards. I guess I assumed jarrah would be too hard to straighten, so I'm pleased to hear you've done it before. Glad I asked! I've got a couple more questions if you don't mind...

(1) Will oiling the underside before I lay really help prevent warping, or is it just added insurance?

(2) Understand tidying up the ends of the boards with a circular saw. But I've got a problem in that the end of the deck is enclosed by a brick wall on one side, and a brick pier on the other. So I'm not able to get the saw close to the outer edges of the deck. What's the best approach here? Tidy up what you can with the saw and individually cut the rest?

(3) The nails are 52mm x 2.5mm SS dome tipped. I presume I pre-drill only the hardwood (not the pine joist) with a 2mm bit? Or should I pre-drill through to the pine aswell?

(4) Now I was wondering about how to make sure I get the nails nice & straight. Sorry to ask such a "green" question, but I'm still learning on this one...... How do I make up a jig?

Thanks again in advance.


Cheers,
Deucer.

Deucer

I haven't straightened Jarrah, but I have straightened blackbutt and spotted gum, which are about as hard as they come. If the quickgrips don't give you enough grunt, get a sash clamp for only a few $$ at bunnies or something and that will do the trick.

Now answers:

1. Not sure exactly what oiling the underside will do. But it certainly won't hurt. Given the amount you are paying for all the bits, I think it is worth the time and effort. Make sure you do the ends too.

2. If I read your message right, is the deck enclosed on 3 sides? Or are you running the boards lengthways between two walls? What are the dimensions of the deck? 1m x 20m is easy, 4x5 is harder.

If it is a fixed width (ie not flexible on either side) it is much harder as you need to be accurate when you measure as you need the exact distance between the joist and the wall.

My recommendation is to buy a mitre saw so that you can get an accurate 90 degree cut. But it will be hard to get it to line up perfectly. Remember to measure twice and cut once. A good way to clean it all up could be to use a jigsaw (as it can get closer to the wall). Another option is to put some kind of skirting board type thing along the edge so that the ends of the boards (which are likely to be different lengths becuase it is hard to cut them all perfectly). Another decking board would do the trick.

3. As for nails, I'd suggest that you use galvanised twist shank decking nails. I've not heard of the dome tip that you have suggested. My only experience with SS screws was terrible. Drill through the decking board only, but it doesn't matter too much if you go onto the pine.

4. A jig is pretty easy. Go to the hardware store and get some normal dressed pine offcuts. You'll need something about 150 or more wide and some narrower bits. The idea is to make a device that fits over the joist snugly (but not too tight) so screw the narrower bits of timber to the wide bit lengthways leaving a gap wide enough for the joist (probably 45 mm joists if t pine so make it just a bit wider) and far enough from one end that it would comfortably fit over the width of a decking board (ie leave about 100mm or more from one end). Now work out how wide your decking boards are and whether you need one or two nails per board. If one, drill a hole that is half the width of the board from the two pine props. If two, the distance between the two holes should be half of the combines total of the board width and the gap width. The distance from the two props should be 1/4 of the combined width. ie for an 80mm board with a 2mm gap, the hole should be 19.5 mm from the two props and the second hole should be 60.5 mm from the props in exactly the middle of the jig. The reason for the complicated maths is so that all the nails over the whole deck are the same spacing. ie the two nails one the one board are xmm apart and the two nails on adjacent boards are also the same spacing. It makes the lines look really groovy IMHO.

It sounds harder than it is and my description is pretty bad. But I've drawn a plan for it to help you out.

Sing out if you don't understand and I will try and translate my gibberish here into english!

Trav

Hi Trav,
Sorry it took me so long to respond to your reply... I've not been able to get near the forum for the last couple of days.

Wow! I figured I'd get some good advise from this forum but you've blown me away with your responses. Thanks so much!

(1) Might have an extra weekend up my sleeve now, so will look at oiling the underside in preparation for laying.

(2) I'm decking our alfresco area which is under the main roof. It's got sliding doors on two full sides and brick wall on half of the 3rd side. The remaining half of the 3rd side and the 4th side are open and are one step down to poured limestone paving. There's brick piers at either end of the 4th side and I'm decking out under the eave up to the outside edge of the piers. So it's essentially a 4.3m x 4.3m square deck, with the exception of the decking under the eaves.

I don't have a mitre saw but do have the use of a friends Triton 2000 table saw, so even though not as efficient as a mitre saw, I'll get there with good cuts.

Re: end cuts, I hadn't even thought of the jigsaw! Good! Now I can put it to use!

(3) Re: nails. Hmmm... Already got the twist shank SS nails (52mm x 2.5mm). Any problems peculiar to SS nails I should look out for?

(4) Thanks so much for the plans for the jig. I read your instructions twice before finding the attached drawing and did understand what you meant. Drawing confirmed it. Thanks for taking the time. This raises another question for me though.... When nailing two board ends to the one joist, how close to the end of the board is it safe to nail? (I suppose I could make up the jig to suit this purpose also).


Cheers,
Deucer.

Some good advice you've got there Deucer.

To clarify, I take it your nails are dome heads, all the better for walking on in bare feet my pretty For max holding power try to avoid drilling into your joists where possible, a small chunka wood on the drill shank limiting the depth to just the decking board would be the go, seeing as you're jig making and all.

Very disappointed you didn't put the mitre saw or, better still, a triton of your own as an essential on the list of requirements to get approval from SWMBO, you still have a ways to go, grasshopper.......... How do you expect the rest of us to keep up this charade when you just go letting the team down :eek:

Speaking of jig making, how about nailing a small block of wood to another piece of a suitable thickness for even spacing of your decking boards? Place spacer between already fixed board and one currently being nailed.

Good luck mate........cheers.........Sean

I'm with scooter on this one. If you can't justify a new saw when you build a deck, you will never be able to! You could get a halfway decent mitre saw for a few hundred dollars. A great tool to have around. Were you going to use the triton to cut all the treated pine too? If so, you'll find a mitre saw heaps easier. I bought a GMC sliding compound mitre saw for about $300 which did the job really well.

I'm sure the nails will be fine. I used galvanised nails, but there is probably little difference. My only tip is to nail it well (ie straight) as pulling out those twist shanks is an absolute bastard!

Measure the thickness of both your jig and and the decking board and add a few mm - this is the length that your drill bit should be protuding from the chuck.

The jigsaw is a crap tool in my view - it is almost impossible to get a nice finish. Try and get something that you can run the edge of the jigsaw against - this will make it a bit straighter.

I didn't bother adapting the jig for joining the boards. Make sure that you join the boards on a joist of course. The trick is to drill on a bit of an angle and stagger your nails so that the nails on the two boards don't hit each other as you drive them in. Your joist will probably by 45mm wide, so give yourself at least 10mm from the end of the board. If it splinters, move it further out!

The other things we haven't written about is the framing. Do you know how you will be erecting the t-pine substructure? Are you using joist hangers or are you cantilevering etc?

Trav

Originally Posted by scooter

Some good advice you've got there Deucer.

To clarify, I take it your nails are dome heads, all the better for walking on in bare feet my pretty For max holding power try to avoid drilling into your joists where possible, a small chunka wood on the drill shank limiting the depth to just the decking board would be the go, seeing as you're jig making and all.

Very disappointed you didn't put the mitre saw or, better still, a triton of your own as an essential on the list of requirements to get approval from SWMBO, you still have a ways to go, grasshopper.......... How do you expect the rest of us to keep up this charade when you just go letting the team down :eek:

Speaking of jig making, how about nailing a small block of wood to another piece of a suitable thickness for even spacing of your decking boards? Place spacer between already fixed board and one currently being nailed.

Good luck mate........cheers.........Sean

Hi Sean,
Yes, the nails are domed head. Saves catching your bare foot on a small chunk of metal I'm told. :eek:

Timber on the drill shank sounds like a foolproof solution. I was thinking of marking the shank with some permanent pen but I guess that's still not reliable.

Yeah well..... grasshopper I still am when it comes to these kinds of projects..... but I did justify a DeWalt 230mm circular saw, Ryobi jigsaw, 3 x quick-grip clamps, Bosch (blue series) 12V cordless drill, 53pce Minimax ratchet set and a few other odds and ends form this project...... I've kept the faith mate!

I guess I assumed that the normal practise is to space the decking boards by the width of the nails you're using (2.5mm in this case). So the approach here would be to tap a nail into the joist between the boards when laying them right?


Cheers,
Deucer.

Originally Posted by Trav

The jigsaw is a crap tool in my view - it is almost impossible to get a nice finish. Try and get something that you can run the edge of the jigsaw against - this will make it a bit straighter.

Trav

Yeah, I figured the same thing..... I'm learning from you real quick Trav... Must have read your mind from the previous post!

Originally Posted by Trav

I didn't bother adapting the jig for joining the boards. Make sure that you join the boards on a joist of course. The trick is to drill on a bit of an angle and stagger your nails so that the nails on the two boards don't hit each other as you drive them in. Your joist will probably by 45mm wide, so give yourself at least 10mm from the end of the board. If it splinters, move it further out!

Trav

Gotcha!

Originally Posted by Trav

The other things we haven't written about is the framing. Do you know how you will be erecting the t-pine substructure? Are you using joist hangers or are you cantilevering etc?

Trav

Sub framings almost all in place. I've got (90x45mm) t-pine ledgers on all walls. Joist hangers to attach the joists to ledgers. Joists are spaced 465mm apart (span?) and they're bolted to 300mm tall metal stirrups cemented into the ground at 1005mm spacings. Galv fixings used throughout. There's no bearers as deck is only two brick courses off the ground. Sound about right?


Cheers,
Deucer.

Deucer

Sounds like you are all set mate. The substructure is about right - I'd normally suggest 400 or 450 centres but 465 should be OK.

Good luck - let us know how you go and if you hvae any other questions.

Trav

Trav,
I was going to go with 450mm joist spans but it worked out that I could space the ledgers & joists evenly between the three walls at 465mm. I seem to remember reading somewhere that the maximum recommended joist span is 500mm for hardwood decking timbers and 450mm for softwoods (or was that 400mm?)..... so figured I'd be ok with 465mm with Jarrah. Think I read this in one of those Mitre 10 style DIY pamphlets.

Does that sound like a generally accepted standard?

Cheers,
Deucer.

Deucer - some of the others should be able to advise if this will be OK. The standard is 450 - so 465 would probably be fine. The wider the gaps between bearers and joists, the more 'bounce' in the deck.

Travis