Some years ago, I built a small tree house in the woods between 3 trees gro wing close together. Well, it's more of a platform really (or flet as it wa s called in those parts, for you real nerds). It is about 6' off the groun d and reached via a rope ladder with 2x2" wooden rungs. The ladder is ancho red at the ground but is still a little wobbly.
A few years after that, but still several years ago, I had some spare treat ed lumber and I added the joists for a second level about 8 above the firs t level. Just recently, after having some deck repair done, I happened to have enough extra deck boards to complete that second level floor.
For now, I have my 6' step ladder out there for access, but I want to build a smaller ladder out of wood to reach the second level. At this height ab ove the ground, I don't want anything wobbly, but I still want it to be fun for the kids (who are much older now) and me (even though I'm older too).
I am envisioning using a couple of 2x4s at a slight angle as the side-rails of the ladder, spaced pretty close together (about 9" between the boards), and then using <something> for the rungs. That's where I want to solicit your advice. :-)
I don't want to spend a lot of money, I want it to be as easy to make as po ssible, and I want it to be able to support a full grown man (who may grow some more sideways). Let's say 225 lbs. - that gives me some growing room ;-) The cheapest, would be to just use 2x2s for the rungs, but I feel if I just screwed them in, they would soon fail from my weight. Ideally, I wou ld cut notches for each 2x2, but I don't relish cutting all those notches s ince the only tool I have to do that right now is a jig saw, and the cuts p robably wouldn't be very well done. Then I thought about using some kind o f round (like a 1.5" or 1.25" dowel or rail). I could easily cut the right sized hole in the side rails, slide in the round, and use a couple of scre ws to prevent the round rungs from swiveling. Unfortunately, I can't find such a thing that is pressure treated at the local stores, and I worry tha t what they have would soon rot and decay outside (though they do have oak at a higher price point, which might last a little longer). They I thought maybe I could use 1" pvc pipe (OD about 1.25") instead of a wooden dowel - it wouldn't rot, but I'm afraid that it would not be strong enough. Final ly, maybe just using pressure treated 1x4 (or event some small leftover dec king boards that I still have), attached directly with 2 or 3 screws on eac h end (no notches) would be strong enough - though I'm not sure about the sheer strength of deck screws or if having more of them effectively improve s sheer strength of the assembly (are nails better?). Any advice or other i deas appreciated.