That Nail vs Screw Question Again

[Clive McF]

I know this question keeps coming up in this forum, and it seems that the answer depends on your individual situation, so here's mine. I'm building a deck around a new chlorine pool, 19 x 90mm hardwood decking on recycled seasoned hardwood joists (not strictly kosher I know, but the joists are only about 1.3m long and came from our old garage. I couldn't bear to throw them out). So, knowing there are arguments on both sides and assuming I’ll predrill all holes, the old familiar question: should I screw or nail in this situation? And then the inevitable supplemental questions:
What size screws or nails?
Galvanised or stainless? (I'd prefer gal due to the $$ but if SS is really the way to go I guess I'd have to bite the bullet)
If I go for screws, most decking screws I can find in large quantities are designed for screwing into treated pine. Can these be used for hardwood, and if not what should I be looking for?
All advice much appreciated: thanks in advance.
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Clive

[rod1949]

I'd be screwing and I'd use the tec screws that are coated for use in treated pine.

[flashman1207]

With the Stainless Steel screws you would definately have to pre drill both the deck boards and the joists (if the joists are hardwood). Even with pine joists the buggers have a tendency to snap........

[Trav]

Definitely have to pre-drill for SS screws. I built a garden screen out of recycled timber and decided to use SS screws. I snapped quite a few screws before I increased the size of the pilot hole.

Anyone have an idea of how much decking screws are? And do you use 2 screws per board per joist like nails? If not, there would be a risk that the board would cup if you only screwed it in the middle.

Trav

[Clive McF]

Definitely have to pre-drill for SS screws. I built a garden screen out of recycled timber and decided to use SS screws. I snapped quite a few screws before I increased the size of the pilot hole.

Anyone have an idea of how much decking screws are? And do you use 2 screws per board per joist like nails? If not, there would be a risk that the board would cup if you only screwed it in the middle.


In the end I compromised: used SS for the edging of the deck where it's nearest the pool and that nasty chlorine, and plastic-coated gal screws further back. SS 8 guage 40mm screws were about $60 for 200 (ouch, but I'm sure I could've got them cheaper by shopping around) and the 40mm Buildex 8 guage coated gal screws were $50 per 1000 from Bunnings. I'm using a compound drill bit to drill the pilot hole and countersink in one go. Cost about $17 and worth every cent. Definitely two screws per board. Following advice from wise heads on this forum I did some dry runs beforehand: as you say, pre-drilling is a must and the diameter, driver speed and clutch settings are critical for the SS screws which are brittle and snap easily when hot.

Clive

[Trav]

I'm using a compound drill bit to drill the pilot hole and countersink in one go. Cost about $17 and worth every cent. Definitely two screws per board.

Clive

The compound drill bit is a good idea. I've used them for cabinet making, but I didn't think of it for decking. Did you find that the countersink became blunt over time?

Trav

[flashman1207]

I'm about 3 quarters of the way into finishing my deck and have used S/S screws throughout (with the square head driver). Some things I learned:

1. Pre-drill the deck wood, especially jarrah.
2. Dip the screw in a solution of detergent and water make the thread slippery
3. Make sure the driver is fully inserted into the screw otherwise it ruins the head
4. Make sure you use a drill with clutch. I have a Hitachi and used the highest clutch setting (22).
5. Screw slowly
6. Use 2 holes per joist and offset them to prevent the joist splitting

I have not yet broke a screw and I've done about 100 so far !!!!

[flashman1207]

I forgot to add that 1300 S/S 10g x 65mm screws cost me $250 I think (Stainless Fastener Supplies in Kewdale, WA) There are only a couple of places in Perth who could supply them....

[strangerep]

The compound drill bit is a good idea.
I've used them for cabinet making, but I didn't think of it for decking.
Did you find that the countersink became blunt over time?

I tried to use a compound drill bit when doing turpentine decking over
tallowwood joists. Absolutely useless. Blunted almost immediately.
I ended up buying a couple more cheap GMC cordless drills so I could
have all the different bits ready to go at the same time. I.e: main hole,
counterbore, countersink, & screw driver.

[flashman1207]

Damn it, I haven't broke any of my SS screws yet but just snapped my 2nd and last square driver bit. I promised 'her indoors' that I would finish the deck this weekend but it ain't gonna happen as Bunnings invariably would not stock them and even if they did you could never find them. Timbecon are not open on Sundays... I'm bu%gered !!!!

Worse thing about snapping them is that they always snap with just a tiny but very sharp bit sticking out of the screw. Impossible to remove....

As for the coutersink bits I used the ones with the drill bit in them as well. I bought 2 (but should have bought 3) as they are pretty blunt after 1000 holes (in Jarrah !!!).... If I ever build another deck I'm gonna buy some stop collars as well as all my holes have ended up different depths.......

[Clive McF]

I tried to use a compound drill bit when doing turpentine decking over
tallowwood joists. Absolutely useless. Blunted almost immediately.


I guess it depends (as always) on your situation: I'm using massara decking on recycled hardwood joists. Done a few hundred holes and so far so good (fingers crossed)... I also use cobalt drill bits (probably not recommended practice but works for me) as they're less brittle and have a slower cutting speed, more compatible with a counterbore speed. This particular counterbore has cutting flutes rather than the ribbed type, which I find generally pretty useless.


.

As for the coutersink bits I used the ones with the drill bit in them as well. I bought 2 (but should have bought 3) as they are pretty blunt after 1000 holes (in Jarrah !!!).... If I ever build another deck I'm gonna buy some stop collars as well as all my holes have ended up different depths.......

Stop collars are a good idea as long as they don't mark the deck of course. But I'm filling the holes so less of an issue for me.

Cheers

Clive

[flashman1207]

Isn't it gonna look a bit crappy with filled screw holes?? Unless you can match the timber perfectly.........

[Clive McF]

Isn't it gonna look a bit crappy with filled screw holes?? Unless you can match the timber perfectly.........

In the eye of the beholder I guess. Personally I don't mind filled screw holes that don't match the timber as long as they're neat circles and well aligned. Let's face it, countersunk screw heads don't blend well with timber either, and they will retain water.

Clive

[flashman1207]

Fair enough, not a problem here though, don't rain much !!!!!!

S/S screws with a square drive head do look nice though !!!!

[Clive McF]

Yeah, would be happy for rain here too. But plenty of chlorinated water from the pool (3 kids + mates) finds it's way onto the deck, which is what worries me...

Clive