Decking Screw Sizes

[hoofy]

I am about to buy a large quantity of Deck-Tite screws for resale to my customers but I am a bit concerned about the size of screw they are offering for fixing the joists together.

They have a 6.5 x 80mm screw and the joists I have to fix together are 100 x 47mm so they would only go 33mm into the end grain of the joists. Is this enough because the next size up they supply is 145mm and they are far to expensive considering how many would be needed to make the frame of the decking.

 

[Thermo]

i always use 90mm annular nails for the framing (i know nails not screws but i wouldnt use 80mm long screws or nails.) Also 145 would be way to long for a lot of the work

 

[hoofy]

Thanks for your reply m8.

I am a bit confused as to the sizes of joist screw that decktite supply. They do an 80mm and a 144mm joist screw. See here.
http://www.screwfix.com/app/sfd/cat/cat.jsp?cId=A431527&ts=60890

Personaly I think 80mm is to small for fixing 100mm x 47mm joists together for the frame. I would have thought decktite would do a screw somewhere in between 80 and 145mm but they dont and you have to remember that decktite are members of the timber decking association so you would have thought (if the screws are the wrong size) that this would have been looked into.

 

[Thermo]

looking at them i think theyre designed for going through the outer frame and into the joist ie 50mm of frame and then the rest in the joist. If thats the case then the theyre the right length. They also look like the they can be used for securing the newel posts. I use a similar version to the timberlock screws, but they have a hex head so are easier to screw in with an impact driver rather than a screw head, which i think will struggle. In the main i dont use them for joist fixing though, i toenail with a paslode nail gun. Its much quicker and easier as the outside face of the frame is not always accesible.

Just because they are a member of the decking asscoiation, doesnt mean they are the last word or option on decking solutions. There is a lot of specialised decking screws/fixings etc on the market which are overpriced, for the construction of what is in essence a very simple floor construction, when traditional tried and tested methods will work much quicker, easier and better