Structural screws- brand?length? Recommendations please!

[ABCwarrior]

Doing my first bit of decking 7.8m x 2.4m. Due to length have essentially split this into 4 equal bays 1950mm long with 5 joists in each.
Was advised to put 3 screws in the end of each joist so each bay needs 42, so need 168 minimum.
What length is best to go for and can anyone recommend a brand that is decent. Those structural ones with bolt heads won't really do as they'll look ugly on visible bits and will interfere with fascias etc.
Where the bays join the top of the joists will be covered with dpc before the boards go down to minimise water getting between them

Toolstation do good looking exterior paslode quattro screws(6x200) but for my needs that's £130 ! Reisser R2's at 6x150 would be closer to £50 but don't know if suitable for outside? We're doing the decks to the joists with the paslodes at 4.5x80, they look the biz.....

I want decent screws for the decking so if it ever needed to be lifted it would be possible(just had to chainsaw/smash up the old decking because those green pozi ones are clearly not intended to come out again...), but is it that essential to do the same with the joist frame? Is it overkill to buy the dearer stuff?

Help- this bit is holding up the job, all ten concrete block pads are concreted in waiting...

 

[masona]

What length is best to go for

Generally speaking, it's 1/3 materials thickness and 2/3 into joists

eg: decking thickness 20mm then add 40mm = 60mm is the minimum length.

I normally go for Decking screws They have never given me any problem

You can pay silly money which is an overkill

 

[ABCwarrior]

Cheers for that Masona, so for 200x47mm joists 150mm would be fine then. Tempted to just go with the Reisser R2 Cutters.
Seems ironic that in being able to buy a higher spec deck board these days, especially composite ones that should never rot, nobody is manufacturing some sort of joist made from material that will last outdoors.
Not rushing this job, the decking will run out from the house rather than parallel to it and The levels on it will be set meticulously to ensure there is a run off from the house out the 2.4m length, and will be covering the tops of all joists with either dpc or mineral felt strips as the gaps between boards always seem to be the worst affected...

The decking we're getting has the "standard" grooving on one side and a very lightly grooved one on the other, so the missus wants the latter on view, the screws can't be hidden therefore which is why we've gone for torx headed ones that countersink themselves- they'll be visible(another headache of aesthetics keeping them all in line!!!)

 

[masona]

the screws can't be hidden therefore which is why we've gone for torx headed ones that countersink themselves- they'll be visible(another headache of aesthetics keeping them all in line!!!)

Well, can be done depends how fussy you are! you can either skew screws underneath if room or L-shape brackets however there's a product called Hidden Deck Fasteners but will need tool which is known as biscuit cutter.

Do a search on hidden deck fasteners, there's plenty difference idea

 

[ABCwarrior]

Eeek...way too complicated that way! Have gone for the R2 Cutters and the Paslode quattros. Toolstation do free delivery only had one pack of each instore, rest due any day now. Tried the Paslodes on a few bits of decking that was ripped out and you can screw through 20mm from the end without a pilot hole. Dogs Boll*cks......

 

[ABCwarrior]

BTW don't know what an acceptable profit margin is these days but got the R2's at 6mm x 150mm (100) for £24.95. In a well known supplier through the Highlands I spotted the same box on a shelf...including vat....£91...WTF!!!!!