Thread: Decking screws

Just been to Bunnings (only hardware around) to get decking screws. I'm confused, what is the difference between 10-8 65mm 306 grade stainless screws and 10G 65mm 306 grade stainless steel screws.

Also should I screw down the decks at every joist, seems a bit of overkill and will mean too many screws visually.

The 10 - 8 is the gauge of the screw and 65 is the length. With 10 - 8 (as opposed to a straight 10) I'm pretty sure the screw has a 10 gauge thread with a 8 gauge head ( smaller). Agree about the visual on screws but you must fix at every joist crossing.

cheers

If lets say one is usin Merbau (19mm X 90MM), would one srew suffice per plank at every crossing or does it need two?

2 screws on a 90 mm board otherwise the board will cup ( lift at the edges). I think from memory that if using nails, they should be 12 mm in from the edge of the board. With screws I would come in a few more mm.

Originally Posted by Dave007

If lets say one is usin Merbau (19mm X 90MM), would one srew suffice per plank at every crossing or does it need two?

Here are a couple of examples of how I have screwed my 90mm merbau deck. From the same edge of every board I have measured in 25mm and 65mm for the screw holes (down the centre of each joist). On each end of the board, as per the join on the top-right of the last picture, I have come in ~12.5mm (my joists are 50mm). I've done about 1950 screws and have got 12 screws to go in.

Well Done. A great looking deck. The effort you have put into using the screws will well and truly pay off over time. No lifting up and any finishing required in the future will allow sanding (if needed) without any hassles

jimj restore-a-deck

Nice one earlybird, looks great. Hardwood or pine joists ? Inspection hatch for pool plumbing I assume ?

Originally Posted by ringtail

The 10 - 8 is the gauge of the screw and 65 is the length. With 10 - 8 (as opposed to a straight 10) I'm pretty sure the screw has a 10 gauge thread with a 8 gauge head ( smaller).

just to clarify, 10-8 means 10guage and 8TPI (threads per inch) so its telling you how coarse or fine the threadform is. The thinner head screws are generally referred to as trimheads (example) and are usually 316 stainless to keep them strong and compensate for the slender profile.

G'day scruff, I've noticed a trend towards the spline drive non tapered head ss screws of late. Is there a move away from the traditional countersunk square drive in your experience ?

HI Ringtail

If you mean this type



then yes it seems to be getting more popular, its actually designed for composite decks such as modwood to stop the mushrooming effect around the head when installing but I've seen people selling it for timber also.

The decking screw market is knackered, sales prices are so low that most distributors have lost interest in them and so consequently they're looking for any other fastener that has some kind of difference or benefit over the standard 10 x 50 Sq drive. I haven't tested any or seen any performance info though so couldn't say if they actually work better or not.

Thats them. There is no way they live up to there promo ( in timber anyway) of no predrilling and no splitting. I used them doing a kwila batten screen and the were very good. Still needed to pre drill though. The heads are far less prominant to look at than a traditional screw. I like them but in a deck application a very small countersink is required to get them under the surface without mushrooming. I stuffed around using a smart bit but not countersinking to full depth - sometimes is was perfect, most times not. More experimenting needed but I like them as a screw much more than the traditional ones.

Originally Posted by ringtail

More experimenting needed but I like them as a screw much more than the traditional ones.

agreed, I liked the look of them as soon as I saw them and thought they'd be great for a more pleasing finish in general construction joinery, we have a good supplier so may look at introducing them down the road but we've too many other things going on for now.

one day eh.

Not trying to butt in however in one of my earlier postings I brought up the idea of replacing dome headed nails with screws. Finally had the opportunity to do several hundred nails with Spax-D screws which are very similar to the drawing . I still used a countersink head with a 3.5mm drill and was very pleased with the final result. It sure made sanding a dream. I lifted each board,turned over,knocked out the nail ,placed board in original position then placed screw in existing nail hole after drilling through the nail hole.

Slow and the screws are 30 cents a pop but will stay where they are suppose to along with any future sanding not a big deal.

jimj

Didi you make the countersink the same size as you would for a traditional screw jimj ? I found they look ridiculous sitting in a large countersink

Yes I would agree that if the countersink hole is to large it can look somewhat odd. The Spax-D screw head is fairly small. Not as small as some trim head screws. I often have to sand trim head decks where the screws are flush. This causes problems with running the abrasives over them not to mention damaging the screws. The Spax-D screws if predrilled with 3.5 drill will self countersink themselves. They have amazing pull down power. It may leave little wooden burrs standing up but easy to sand off. You can set a guage on your drill to stop when the screws reaches the depth you want. All of this can take a little trial and error with some practice on off cuts but once you have what pleases you can get through it fairly easily.
Diversity of ideas shared is what makes this forum so enjoyable

jimj restore-a-deck

I might try and make something up. I dont like the notion of having to sand a new deck just because of the fixings

Originally Posted by ringtail

Nice one earlybird, looks great. Hardwood or pine joists ? Inspection hatch for pool plumbing I assume ?

Thanks, extremely happy with it, especially for the first go at deck. The joists are pine on gal bearers. The hatch is to pull the cartridge filters up through - there is not enough clearance between the filter and the deck. I was thinking of putting in a stainless handle (the sort they use on a boat), however I will probably leave it as it is. I will most likely be under the deck to open the filter first, so I can just push the hatch up and across from below.

A stainless ringpull would look good though. You need hatch access from the top so you accidentally drop the salad off your steak burger down there

A great looking job!
Not to hijak this thread, but I'm interested to know what you guys think of the Smart Bit system?

I'm hoping to win an on line auction for a 50 sq m merbau deck which is nailed, so when rebuilding it I'd like to screw it down. Can I use this system knowing it won't stuff up the job as it's my first go at this?

Smart bits work well. Get the right size for the screws you plan to use. Are you bidding on decking that is nailed down ??? Mmmmm.

I was, but it went for a lot more than I thought...

I have 140mm boards, so going by the photos above, should we use 3 screws in each support beam or would 2 still be ok? is 55 or 65 gauge preferred for 22mm timber?
thanks

Originally Posted by knoath

A great looking job!
Not to hijak this thread, but I'm interested to know what you guys think of the Smart Bit system?

I hear mostly good things about the smart bit. I used one and wasn't that impressed. I found it left black ring marks if the guide touched the timber (cypress).

I've decided on screws based on this thread (the idea of fixing nails later on put me off). Anyway, went to Bunnings and bought a whole bunch of Zenith 316 stainless 50mm 8G screws. Also bought some 65mm 10G screws for fixing handrails (keeping with stainless look), some 3.5mm drill bits, a countersinking bit and a new AEG cordless drill. I guess my Ozito will probably won't handle the distance.

Today I did a few practice runs. Pre-drill with 3.5mm bit & countersink. Set cordless clutch to 8 (out of 24) and let rip. First 3 = snapped screw, 4th I managed to get it in without any problem (and I quite like the look).

So my questions are:

1) What to do if I snap my screws? What's the fix?

2) What do people use for fixing handrails? I'm a bit concerned about stainless. I never snap galvanized batten screws. Therefore, are they stronger?

3) What to do if I snap drill bit?

Thanks in advance.

Hi baileyboy

The way to prevent snapping screws is to pre drill with the correct size smart bit or clever tool, (see knoath's photo) and then drive them at low revs with hi torque, an impact driver is the best for the job.

Snapped or damaged screws can be easily removed with a Grab It screw remover. They drill into the screw in reverse and remove it.

Broken drill bits are a different matter and difficult to remove (use nail punch and drive into the joist if below surface, or use pliers to unscrew if above the surface) so take care when drilling and they wont break.

I hope this helps you.
G

Originally Posted by knoath

A great looking job!
Not to hijak this thread, but I'm interested to know what you guys think of the Smart Bit system?

I'm hoping to win an on line auction for a 50 sq m merbau deck which is nailed, so when rebuilding it I'd like to screw it down. Can I use this system knowing it won't stuff up the job as it's my first go at this?

I am in the process (1800 down, 700 odd to go) with the smart bit. Good points: does what it says, drill till the collar stops, and your done. It didn't mark my deck at all (red ironbark). Bad points. The drill bits break easily. The bigger flutes work okay, but I ended up using regular 3.57mm bits, cut down to the right length, then grind a small flat on them. You get 10 replacements for the price of 5 smart-bit ones. Works just as well, but actually more durable. You do have to touch up the countersink section with a small file to keep it sharp, and in the future, I think they should make the c/s part replaceable as this is the bit that makes a difference. They do tend to make a small mushroom/flare at the edge of the hole, but this may vary on the type of wood. I would try it, and see, cos it does take a lot of work out of it, and gives you a uniform hole.

Cheers
James.

Must comment to that, its entirely dependent on your deck material. Ive used a smart bit on my deck (Tallowood decking boards and joists) and havent snapped a drill bit at all, only bluntened one after ~2000 screws.

I agree. I drilled a whole deck with a smartbit couple weeks ago and didn't snap one either

Originally Posted by stevoh741

I agree. I drilled a whole deck with a smartbit couple weeks ago and didn't snap one either

Fair enough, maybe I just got a dud batch, as one of the bits was blunt out of the pack too. Or I am just a bit unco... haven't snapped the other bits though.

Thanks I went and bought myself a Smart tool.

I predrilled as per the Zenith instruction. 3.5mm hole. I was probably too eager and pushed too hard...

Originally Posted by platboy

I am in the process (1800 down, 700 odd to go) with the smart bit. Good points: does what it says, drill till the collar stops, and your done. It didn't mark my deck at all (red ironbark). Bad points. The drill bits break easily. The bigger flutes work okay, but I ended up using regular 3.57mm bits, cut down to the right length, then grind a small flat on them. You get 10 replacements for the price of 5 smart-bit ones. Works just as well, but actually more durable. You do have to touch up the countersink section with a small file to keep it sharp, and in the future, I think they should make the c/s part replaceable as this is the bit that makes a difference. They do tend to make a small mushroom/flare at the edge of the hole, but this may vary on the type of wood. I would try it, and see, cos it does take a lot of work out of it, and gives you a uniform hole.

Cheers
James.

James this is my first post so hope it makes sense. I to will be installing Red Ironbark decking over treated pine bearers/joists. What size screws did you use 50mm/65mm? What oil/stain did you use.
Also I will be putting up some Ironbark weatherboards (shiplap) on softwood framing. I was thinking of using stainless screws possibly 8 gauge. Any thoughts by forum members?
Thanks Graham

Originally Posted by Up Bush

James this is my first post so hope it makes sense. I to will be installing Red Ironbark decking over treated pine bearers/joists. What size screws did you use 50mm/65mm? What oil/stain did you use.
Also I will be putting up some Ironbark weatherboards (shiplap) on softwood framing. I was thinking of using stainless screws possibly 8 gauge. Any thoughts by forum members?
Thanks Graham

Hi Graham - I used 10 gauge 50mm screws for the decking. I haven't finished yet or oiled, but was thinking of cabots oil-based natural. Despite some people saying it can leave the timber a bit yellow (like using egg yolk) I tested some and it came out nicely. Just got to remove the excess oil before it dries.

Cheers'
James.

Originally Posted by jimj

Yes I would agree that if the countersink hole is to large it can look somewhat odd. The Spax-D screw head is fairly small. Not as small as some trim head screws. I often have to sand trim head decks where the screws are flush. This causes problems with running the abrasives over them not to mention damaging the screws. The Spax-D screws if predrilled with 3.5 drill will self countersink themselves. They have amazing pull down power. It may leave little wooden burrs standing up but easy to sand off. You can set a guage on your drill to stop when the screws reaches the depth you want. All of this can take a little trial and error with some practice on off cuts but once you have what pleases you can get through it fairly easily.
Diversity of ideas shared is what makes this forum so enjoyable

jimj restore-a-deck

I agree with jimj, I just pulled out over 2000 Spax-D 5x55 A2 and none and all can be reused when flipping the boards. Although I used the drill speed on my Hitachi less then 20 screws were messed up. No rust at all alltthough near the pool. I also had a section with some other screws, not Spax and not A2 and less then 1 in 10 could be pulled out - the rest were snapped in the board or joist...

Based on my limited experience - Spax-D A2 are great.