[btl_rkt_sci]

I'm planning to build a swing set for my kids by hanging a beam between two large trees. The trees are about 18' apart, though. Is this a longer span than you'd feel comfortable covering with a 4x6 or 4x8 beam?

Also, if I use pressure treated pine I was thinking of using 2-3 layers of 2x and joining them with adhesive and fasteners to keep the warping in check. Should I just go with a solid 4x beam? What about cypress or white oak (likely not dried heartwood).

Finally, what's the best way to secure the beam? I was thinking of putting a lag bolt into each tree with a few extra inches on the bolts and drilling a slots into the beam, so it could slide back and forth, side-to-side on the bolts. Then I could use steel cable and turn buckles from higher up in the tree to add support closer to the center of the beam, if that's necessary.

Let me know what you think.

 

[ryansdiydad]

I think just build a A frame on each end and not worry about the tree.. It would be way way way less work.. Could get the entire thing up in 20-30 minutes and not have to worry about Jerry rigging some connection to the trees.. 18' is a long span..

 

[btl_rkt_sci]

I guess I should add that these are very mature trees. A white oak at least 24" in diameter and a southern magnolia at least 16". I don't predict there is more than a few centimeters of movement as high as 12' off the ground.

 

[btl_rkt_sci]

Thanks for the input, ryansdiydad. I'd have to say that the safety of it is more of a concern than the amount of work involved. If I go the route of putting a post on the ground, I'm going full treehouse or a DIY hardware-kit playset thing. Just like the novelty of using the trees if I can, I guess.

 

[ryansdiydad]

You have more than just downward force to worry about so need to consider that in the beam sizing and supports.. Also don't need to put posts in the ground for the a frame.. Maybe this will give you some inspiration either way. http://www.carolinabackyards.com/The_Swingset.html

http://pecchia.blogspot.com/2011/07/swing-set.html?m=1

 

[btl_rkt_sci]

Those are pretty nice. I found some load charts for lumber and I think I'd at least have to add an A-frame support halfway between the trees. But, I may just build one A-frame support and hang the other end of the beam off one of the trees - going with a shorter beam (12-16').

One thing I liked about using the trees is that I didn't need to worry about the ground being leveled. Our whole yard is on various grades and leveling the ground is something I really don't want to do. Knowing me, the "precision" part of cutting the A-frame to make sure the beam is level will be a frustrating challenge. Any tricks of the trade there?

 

[Clutchcargo]

Could you connect a chain or cable between the trees and simply hang the ropes for the swing off that?