Canberra Deck, photos up - help need with nails

new link

http://www.timber.org.au/menu.asp?id=140

download the pdf file

the 50mm ss screw had 5 times the amount of holding power in hw compared to a std flat gal machine driven for instance - 1.1kn is considered adequate, a ss 50mm screw achives over 10kn in HW, probably half that in soft wood or 5 times minimum! (HW and SW relates to the joist material)

for decking type, its the head type that counts for withdrawal when looking at TP, as its most likely that will be the failure point - so bullet heads in 2.3 would be very much marginal in holding power for TP deck.

BTW you cant do much harm by going 65mm, but if 50mm out performs most other fasteners by a factor of 5, its sort of hard to justify I think....... ;)

Each to there own as for screws verse nails... When i get round to it i'll post the photo's i took today of a deck done at the end of december 07 so 2 months old ..its merbau boards with merbau joists and nailed with a screw shank stainless nail put in with a duofast coil gun... The photo's speak for themselves...

Stay away from the extension screw drivers that put the screws in off a strip .. They self drill and self countersink ... It doesn't work with hardwood..they split the boards at best and don't have enough strength to drive flat.. The company rep spent a good 30 minutes trying to prove me wrong only to say in the end that american decking must be softer..

Stay away from the Gal screw as most aren't really heavily galvenised and rust pretty quick aswell as having thin shanks and snapping..
The discolouration from the merbau on the heads is the boards leaching and they'l do that on anything for the initial period..

If you buy a carbitool counter sink and pilot it'll counter sink and pilot the board in one... You set the drill bit to just pilot the board when the sink is at the right depth..

50mm screws is plenty for 19mm decking into treated joists

190 buck per thousand aint cheap...

A good retail price is closer to 150 per thousand

I'll let the screw Vs Nails debate roll on ... But i think i will opt out as it bores me to no end LOL

cheers utemad

Hey has anyone seen or heard about gold 10g screws before? :rolleyes:

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Originally Posted by PRKLCD

Hey has anyone seen or heard about gold 10g screws before? :rolleyes:

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:oo:No, but my first thought is yuck:oo:

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Originally Posted by Burnsy

:oo:No, but my first thought is yuck:oo:

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That's what I thought - but I was talking to a builder at the gym and he reckons wit Merbau it looks really good.

I will see if I can get some gold ones today to do a test run. Will let people know what it's like

EDIT:ok gold ones are just zinc coated screws - no good for decks - my bad

Was just about to post that... Internal use only.. Must be some builder hey!

cheers utemad

Quote:

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Originally Posted by UteMad

Was just about to post that... Internal use only.. Must be some builder hey!

cheers utemad

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Yeah he is a 1st year apprietence - glad they aren't building my deck :oo:

Just my two-bob's worth - 50mm for screws into TP is fine and 65mm would be overkill on cost and utility ground.

Although nails can be re-punched a tighten up of the screws after a bit of time with shrinkage etc will give a much better technical result than nails if you are OK with the extra initial cost and time to put them in. You see the holes or the heads if they are the domed type with nails, and the heads with screws so that is an aesthetic issue only.

If time is your concern then nail guns work OK (which is why builders tend to use them), but with almost all hardwoods you will get splitting. All ends should be pre-drilled in any case. It is not uncommon to see untreated nails used from guns and they will fail rapidly.

For TP you should use those fasteners especially coated for use with TP (not gal or gold zinc which corrode rapidly) or SS as you are leaning towards.

Pre-drilling need only be through the boards not into the TP underfloor.

Thanks for everyones help with this - it's been great.

I ordered the SS screws today, all ready for the weekend. I am going to use 5mm spacing between the boards.

I am interested in finding out about this "5th board down" approach - I have had a search but can't find anthing.

Any tips for ensuring the screws are in a straight line?

More Pics tomorrow!

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Originally Posted by PRKLCD

Any tips for ensuring the screws are in a straight line?

More Pics tomorrow!

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A string line with a nail at the end of each joist and progressively move the string as you go along.

As Waldo said PRKLCD, maybe to save a little bit of time if you are screwing, is to use a string line every 3 or 4th joist as in the picture. you just have to pull the string down at each new board and come back later to infill the joists you missed with a screwed string line. Depending on how straight your boards are, the more space you can have between initial screws.
You won't be disappointed with the stainless, for a few extra dollars i think they give a better look.
Hope your back and knees are ok though, takes a lot out of them. I used knee pads which helped alot.
I didn't use the 5th board method, but i think the main aim is so you can clamp 5 all together and screw down, then measure out 1 board width then clamp another 5 and so on, then fill in the missing boards. Don't quote me on it, i've only just screwed my first deck myself.

Good Luck

Stew

Just remembered...... Make sure your pilot hole for the merbau is the same size or a fraction bigger then the screw size. Snapped heads will be common otherwise and the remaining threads are a bitch to get out without ripping the crap out of your board.
I snapped too many before realising if your board isn't flat on the joist you are trying to pull the two together with your little thread on your screw and its too much for it to handle. ($40 wasted on a 3.2 Carbitool)
Board pulls down fine with a coutersink a little smaller than screw head diameter, and let the screw do the rest... :U

. ($40 wasted on a 3.2 Carbitool)
:U[/quote]


How so??

Cheers utemad

I bought the 3.2 from reading one of the posts here which said would be suitable for a 10g screw. I found the 3.2 pilot was too small and was subsequently snapping heads off cause if the board wasn't flat on the joist, the screw would thread (bout5mm dia) the board then thread the joist then when trying to pull the two together with the thread, it was too much for the screw. I hope i didn't confuse more than explain.
It won't be a total waste, it will sit on the bench for a while but i'm sure the wife has another project just around the corner where i can use it again......

Stew

Quote:

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Originally Posted by Spider Webb

I bought the 3.2 from reading one of the posts here which said would be suitable for a 10g screw. I found the 3.2 pilot was too small and was subsequently snapping heads off cause if the board wasn't flat on the joist, the screw would thread (bout5mm dia) the board then thread the joist then when trying to pull the two together with the thread, it was too much for the screw. I hope i didn't confuse more than explain.
It won't be a total waste, it will sit on the bench for a while but i'm sure the wife has another project just around the corner where i can use it again......

Stew

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Hi Stew

The 3.2 is the size for 10G screws. My offsider bought the 8G one by mistake once for a job which is too small and suffers the complaints you listed

1. Fistly you set the pilot bit to a depth so when the countersink just reaches the point where the screw would be flush the pilot just breaks through the board..
2. Before laying the deck check that the tops of the joists are reasonably flat and if there are any major discrepancies like more than 2-3mm plane them or pack them..
3. When buying the screws make sure they are true 10G type 17 screws and not stainless 8-10G pin pointed chipboard variety that have a thinner shaft and will snap if over tightened
4. The best tool to put them in is an impact driver from our experience as you can hit the board and then fine tune if necessary.. Roofing guns do a rather average job as they don't have the torque to add the extra bit nor do power drills..
5. If the boards hair up around the head the countersink is to small or too shallow.
6. If your snapping screws then you most likely bought the wrong ones or like you said the joists weren't flat so the screws were under enormous strain trying to pull hardood down a few mm over only 450mm something that a nail would never have a hope of achieving anyway.. We would shatter probably 1 maybe 2 driver bits on an average deck just from the impact driver and possibly break 1 or 2 screws but these would be from hitting another fixing in the joist like a gun nail or bolt and not just into normal pine timber

They are a great countersink and i hope you find some use for it in the future. If you break the drill bit its a standard 1/8 bit which makes replacement easy..

I hope your deck came up a treat

cheers utemad