My goal.

[Swat Runs Train]

There's lots of exercises for your chest and back, you don't need heavier weights to rely on. If you rely on that for getting bigger in areas like that, you'll only end up doing exercises improperly because you won't be focused on technique when lifting them or doing whatever you're doing with those weights. Like any mass building though you need heavy weights anyway.

I believe he only has 20lb weights, even a beginner can bench, shrug and row more than 40lbs, pushups and pullups will only do so much.

There's a difference between heavy and too heavy, I am obviously aware of the fact that he shouldn't sacrifice form for weight, thanks though.