My first attempt and Deck building

I got two stupid questions for you.
a) What do u mean by Canti?

b) What are the 100 x 100mm squares with the circle in them at the bottom of your plan??

Excuse my ignorance.

Thanks

I reckon Canti = cantilever, of which silkishuge has 240mm, and the squares are showing the stirrups/stumps creating the Canti - but are offset for 'ease of drawing'.

"Joist/bearer Spacing" in the span tables is measured to the centres of the timbers (not the space between). Your 450mm between joists are actually 495mm centres, and should be 450mm centres - yeah, it's only 45mm difference, but you are looking to use 19mm boards...

3 x Bearers (DxB) = 190 mm x 45 mm FLW = 1500mm, Max Span (F5) = 3250 mm Max Canti = 920 mm
I reckon the span tables say you should have 2 x 190x45 for each bearer, i.e. two lengths vertically nailed together (that's what "2/190x45" means)

7 x Joist (DxB) = 190 mm x 45 mm, Max Span continuous (F5) = 3600 mm, No canti space
Your joist span is actually 1500mm (centres of bearers), so you could use 120x45

Decking dimensions 90 mm x 19 mm.
I used 90mm wides for my deck, but would try and get 120 or 140 for my next effort for a 'more substantial' look.

Estimate ~ 96m length of decking board. Give a 25% allowance, 120 mof decking boards.
You should be able to minimise this contingency. Ask what you can get before you order. Some timber yards will let you hand pick your lengths. It's worth it. Looking at a pile of large offcuts is depressing and expensive.

At $7/m, cost of boards ~ = $840
$7/m seems a lot - what wood were you thinking of, out of interest? Merbau is around $5.30/m where I live.
.
32 boards wide and minimum of 4 screws per jwith joist. 7 joist, therefore 32 x 4 x 7 = 896 screws. ($25)
I would use 2 screws per joist per board - the aboive looks like twice as much as you need, except where butt joining. a box of 500 should be enough depending on how many butt joins you need. (if you go for 120 or 140 width boards, use three screws at each joist)

Originally Posted by r3nov8or

"Joist/bearer Spacing" in the span tables is measured to the centres of the timbers (not the space between). Your 450mm between joists are actually 495mm centres, and should be 450mm centres - yeah, it's only 45mm difference, but you are looking to use 19mm boards...

Wow, thanks for that. I did not know. I might have to include more joists.

Originally Posted by r3nov8or

3 x Bearers (DxB) = 190 mm x 45 mm FLW = 1500mm, Max Span (F5) = 3250 mm Max Canti = 920 mm
I reckon the span tables say you should have 2 x 190x45 for each bearer, i.e. two lengths vertically nailed together (that's what "2/190x45" means)

I was wondering what that "2" meant. Is there a span table which only uses a single bearer?

Originally Posted by r3nov8or

7 x Joist (DxB) = 190 mm x 45 mm, Max Span continuous (F5) = 3600 mm, No canti space
Your joist span is actually 1500mm (centres of bearers), so you could use 120x45

That is perfect. A lower deck is ideal. I am still trying to find the best design for stairs.

Originally Posted by r3nov8or

Decking dimensions 90 mm x 19 mm.
I used 90mm wides for my deck, but would try and get 120 or 140 for my next effort for a 'more substantial' look.

Might consider this. I will have to make a side by side comparison of the two. The 140 board would really reduce the number of board widths I need to finish the deck.

Originally Posted by r3nov8or

At $7/m, cost of boards ~ = $840
$7/m seems a lot - what wood were you thinking of, out of interest? Merbau is around $5.30/m where I live.

I should do a bit more research on this. I have not decided on the decking material but the number I got was from a Bunnings advertisement in the mail.
.
32 boards wide and minimum of 4 screws per jwith joist. 7 joist, therefore 32 x 4 x 7 = 896 screws. ($25)
I would use 2 screws per joist per board - the aboive looks like twice as much as you need, except where butt joining. a box of 500 should be enough depending on how many butt joins you need. (if you go for 120 or 140 width boards, use three screws at each joist)
[/quote]

Okay, this is probably a dumb question...... does this mean that at no time will two ends of a decking board meet at a joist where they are screwed in together on the same joist? I had the impression that the the ends of each decking board must be secured down to a joist, so that means the ends of each decking board will meet on a joist.


Thanks again. Appreciate you taking the time to point out so many details.

Jon

Originally Posted by silkishuge

Wow, thanks for that. I did not know. I might have to include more joists.

Yeah, but probably only one more.

I was wondering what that "2" meant. Is there a span table which only uses a single bearer?

Not in treated pine. Gal steel is an option. Once you know your exact measurements you could get a PFC ("C" beam) prefabbed with brackets. Not cheap though.

That is perfect. A lower deck is ideal. I am still trying to find the best design for stairs.

Stairs! Now, that is something I must have a go at too.

Might consider this. I will have to make a side by side comparison of the two. The 140 board would really reduce the number of board widths I need to finish the deck.

Yes, but you pay a premium for wider boards so may not save anything, may even work out more... It's all about the look you want (to pay for)

Okay, this is probably a dumb question...... does this mean that at no time will two ends of a decking board meet at a joist where they are screwed in together on the same joist? I had the impression that the the ends of each decking board must be secured down to a joist, so that means the ends of each decking board will meet on a joist.

Yes, decking boards must end on a joist, and must join on a joist. If your board fully spans a joist (which it hopefully it will do most of the time for a 3m deck) then the only time you will need four screws per board per joist is when you need to butt them together over the joist (2 screws per board-end, with half of the joist being used by each board-end. Measure twice, cut once)

Thanks again. Appreciate you taking the time to point out so many details.

No problem at all.

140 look good, and not much dearer on sqm basis. I ahve a small deck next to my pool with 140. Only problem is being exposed they tend to cup upwards, not as noticeable with 90 wide for the rest of my decking

if the deck is only 3x3 you should be able to get 3.0 and/or 3.3 lengths so no need for a join. Some places will try and charge a premium for set lengths so look around

Thanks bpj1968. Regarding the lwying of decking boards, I read from an online decking article that boards next to each other should not end on the same joist. Can someone please confirm this?

Thanks,
Jon

Originally Posted by silkishuge

Thanks bpj1968. Regarding the lwying of decking boards, I read from an online decking article that boards next to each other should not end on the same joist. Can someone please confirm this?

Thanks,
Jon

Unless, of course, it is the first or final joist

If you need to butt join boards, is it stronger overall, and also looks much better, if you stagger the joins.

It is also best to have continuous spans for boards, i.e. each board over at least 3 joists. As bpj1968 says, you should be able to source long enough lengths to avoid many joins.

Just adding to R3nov8ors comments; it's best practice to make your decking boards run over at least 3 joists, short pieces of decking that sit on only 2 joists both look ugly and can be unstable. They can be particularly unstable if they are on the ends of the runs.
I always prefer to stagger the nails as well, I don't put them in a straight line as this can encourage the joists to split more easily.

Originally Posted by julianx

Just adding to R3nov8ors comments; it's best practice to make your decking boards run over at least 3 joists, short pieces of decking that sit on only 2 joists both look ugly and can be unstable. They can be particularly unstable if they are on the ends of the runs.
I always prefer to stagger the nails as well, I don't put them in a straight line as this can encourage the joists to split more easily.

More good tips.

Thanks r3nov8or for the advice too. I worked out that I will now have to use a joist spacing of 415mm and that requires an additional joist. So that makes 8 joist in total and 6 bears (1 pair of bearers every 1.5 m). How many bolts should I use to bolt the bearers together and what is the distance I should use between each bolt along the length of the bearer.

Thanks,
Jon

This basically covers it http://www.wespine.com.au/naillam%20beam.pdf

"Nail-laminated MGP pine beams can be fabricated
easily on site in accordance with framing code
requirements, using 65 to 75mm standard gun nails
spaced apart at twice the board width and doublenailed
at the ends and at point loads (as per the
diagram from the code)."

So no need to use bolts, but long nails. I went a little further than the above, used 100mm nails and bent over the protruding 10mm on the opposite side.

Originally Posted by r3nov8or

This basically covers it http://www.wespine.com.au/naillam%20beam.pdf

"Nail-laminated MGP pine beams can be fabricated
easily on site in accordance with framing code
requirements, using 65 to 75mm standard gun nails
spaced apart at twice the board width and doublenailed
at the ends and at point loads (as per the
diagram from the code)."

So no need to use bolts, but long nails. I went a little further than the above, used 100mm nails and bent over the protruding 10mm on the opposite side.

Thanks mate. Sounds like there are alot of options. I think I will spend a little more time doing research an plan it out well before buying materials.

Jon

Maybe it seems more complex that it is.

Lay the two timbers together precisely and clamp. Two nails go at each end. You are using 190mm, and 2x190=380, so nail every 380mm along the length in a 'saw-tooth' pattern and you have yourself a 190x90 bearer.