Ready for the P5 chipboard.
This is 22mm high density water-resistant T&G board. A urethane glue is used on each joist and round all the edges. Each board is screwed into each joist, and where appropriate, any noggins. About 300 screws there.
There are 17 joists, one stringer and 48 noggins,. Each noggin has 4 5x100 (or 6x125 if they are going through the 63mm joists) galvanised joist screws, i.e. about 200 screws. Most of the joists are 47x125 but two are 75x125.
The.board weighs 15kg/M2 and the joists & noggins weigh 270kg, making a total of about 540kg for the floor. The 6M steel C section weighs 90kg and is retained by 16 M10x135 A4 stainless resin bonded fixings.
To torque all the fixings accurately I invested in a digital torque meter. For the 100s of big screws, I used a Makita DTD152Z impact driver - a totally magic tool that makes driving loads of big screws a complete doddle... A lot of tool for the money...