When I try to drive a screw through 2x4's I typically find that it's just too hard - there's too much resistance in the wood and I end up spinning in the screw head.

I use a mid-level Black and Decker cordless drill/screwdriver and phillips head screws. A guy I know who builds fancy treehouses always uses a square-head screw.

Is the problem my choice of screw head, my driver or both?

 

Phillip heads can do that. Some prefer square (Robertson) drive, and Torx are very popular. Unless it's a drywall screw, I don't use anything but torx. They don't slip unless you're drunk or something. Not that I would know.

 

Phillips head screws do tend to cam out the most which leads to stripping the screw. Square and Torx heads screws help a great deal in preventing cam out. However driving screws through 2x material is still a tough job for some drill/drivers.

One of the biggest improvements in driving screws is the use of cordless impact drivers. They will drive/spin a screw at full speed, and then when the resistance gets to a certain level it switches to impact mode to drive the screw in. In impact mode it is fairly easy to drive 3" Phillips screws into 2x material.

It can also help to switch your B&D driver to low speed and pre-drill a hole slightly larger then the screw before driving the screws.

BTW - I hope your only using screws for the decking and not for the framing material.

 

I would invest in an impact driver to compliment your drill. You have a "drill", and that is what it was meant to do, not drive screws. The impact driver drives screws, and doesn't drill, so they are two separate tools to add to your toolbox.

 

When we rehabbed our daughter's deck we used the torx deck screws driven with my cordless drill on the high torque/low speed setting. Worked very well.

 

An impact driver is the right tool for the job, but that's incorrect that it can not drill holes.
I almost never use my drills anymore unless using larger bits or drilling things like steel or concrete.
In fact any of these bit sets will work in one.
https://www.google.com/webhp?sourcei...t+set&tbm=shop
I use mine to drill holes, drive screws, even can use sockets to drive bolts and nuts.

 

Joe, once the impact driver reaches the apex of it's ability to spin, it will start impacting, not making a good drill, but a stutter machine. Yes, they will drill holes, but a drill is meant for the job.