Decking frame screws..

MidlandsGlory

Hi,
Building a low level (so fully supported frame) deck, what size and type of screws (for good shear strength) would people recommend for fixing through 47mm frames into the ends of 47mm joists?

I don't suppose outdoor framing wood is that dense so a good depth into it will be needed to hold fast so at least 120mm screws? maybe 5mm thickness? Would hex head ones make driving easier (will pre-drill anyway)

Thanks, always try to do my research before doing something the first time, ask once, fix once!

WillowCat

I've built a couple of decks and an entire cabin using these https://www.screwfix.com/p/goldscrew-pz-double-countersunk-multipurpose-screws-6-x-100mm-100-pack/16784

6mm means they are a little chunkier, and 100mm length has been more than enough (they countersink well into the wood so nearly 60mm is in the joist.

They're a pozi 3 head and I've never had trouble driving them.  I also drill a pilot hole.

casper_gutman

I'd get some with a Torx head personally. I've been slowly using up a big box of Pozidriv Goldscrews I bought ages ago, but it's taking forever because I keep using Torx in preference to them.

There's nothing worse than driving a long framing screw most of the way in then hiting a knot, having the driver slip and stripping the head.

The manufacturers often put a driver bit in the box with the Torx screws anyway, so there may well be no special tools needed even if you don't have a suitable driver already.

casper_gutman

I used these for a similar project (actually a base for a log cabin, but they'd work well for a deck frame I'm sure): https://www.screwfix.com/p/timbascrew-wafer-timber-screw ts-gold-6-7-x-100mm-50-pack/1792j
I drilled a pilot hole for the first few, but the box said this was "not normally required" so I tried without when I got a bit more confident and they still went in beautifully.

MidlandsGlory

casper_gutman said:

I used these for a similar project (actually a base for a log cabin, but they'd work well for a deck frame I'm sure): https://www.screwfix.com/p/timbascrew-wafer-timber-screw ts-gold-6-7-x-100mm-50-pack/1792j
I drilled a pilot hole for the first few, but the box said this was "not normally required" so I tried without when I got a bit more confident and they still went in beautifully.

I saw something the same on Toolstation, but wondered if the heads might shear as there is no thicker reinforcement behind it like on a normal countersunk. Glad they worked well for you. I suppose a 6.7mm screw should be strong all round with that thickness of steel..
cheers