just like any other diy job, distributing the weight
is a good idea.

drilling a pilot holes and inserting the bolts
will weaken the joist.
it would be best to spread the weight to seperate ceiling
joists, rather than putting all the wieght on one joist.

increasing size of bolts increases
weight to be supported.

First consult a span table to determine how close to max span the joist system is, just incase you are planning a traverse tract system, for other points of interest within the living space.

That's an interesting question, where's a structural engineer when you need one... ;-) Most ceiling joists aren't designed to support a large load but I don't know what load they are designed for.

My gut reaction says to sister the joists in question with another 2x6 (glue and screw to the existing joist) and maybe put in lumber long enough to rest on load bearing walls. Then attach your swing to the sistered joist. I just don't know if it's necessary to go to a wall or smaller piece of lumber would be sufficient. I would imagine it very much depends on where in the span the attachment point is.

Of course the hardware that comes with the unit is as simple as it can get i.e. two 1/2 in. eyebolts. Not sure I'd truct that configuration. Personally I would sister another 2x6 and then run a piece of 1/2 in. trheaded rod between them with a 3/16 to 1/4 in. steel plate bearing on the top of both of the joists, essentially hanging the swing from the top of the joists as opposed to relying on pull out of the screw anchor from the bottom of the joist. You could then use a coupler and a threaded eye bolt to hang the swing. Make sure the ends of the supporting joists are bearing on a supporting wall all the way to the basement if you're on an elevated floor. Remember the weights you are using are static weights with no allowance for dynamic loads from the swing, so actual loads are likely higher.

Also, make sure you consider any potential lateral forces, maybe by putting some header type braces to the adjacent joists

My 0.02.

Provided you make sure the screw eyes are centered, I think it would be more than adequate since they are close to the walls. But doubling up the joist and bolting it together wouldn't hurt. Stagger the bolts a bit, if you do. Predrill all holes, of course.

NO! NO! NO! NO! You MUST NOT drill the joists. No doubt they are part of an engineered truss, and you MUST NOT compromise it by drilling it. You'd create a weak point.

I agree that distributing the load is the answer..

Sistering several joists is not a bad idea, with a cross-piece across them, which would take the load, via blocking. You need to support it across several joists, ideally sistered. You don't want it creaking.

I'd throw away the screw-in bolts, they're not safe. You need an eyebolt that's threaded, and long enough so that you can use nuts and washers on the wood in the attic, so that the bolts are supported by the nuts and washers (and you need two nuts on each, as a locking feature.)

Not all drilling of even engineered trusses for water supply lines and electrical (DWV lines are often large enough to be a problem) cables does not have any significant effect on them.

Try and avoid using any type of threaded fastener in withdrawal (tension).
The unscrewing hazard is the least of the problems.'
You want the fasteners to go perpendicular to the length of the joist.
In one side, out the other, washers and nylon locking insert nuts.
This may mean you need to fasten blocking to the side of the joist that goes though the finished surface.

Doubling up the joist in the area and drilling all the way though vertically and them using blocking to spread the load now at the top of the joist is a very good method.

This post was edited by brickeyee on Fri, Jan 25, 13 at 10:26

I can't help but think we've over engineering this project but maybe I'm not understanding how this swing is used. My initial thought was that it would be swinging in a relatively small arc of maybe 6-8".

I'm wondering about the effect of strength on a joist with, say, a 1/2" hole drilled vertically through it?

Blocking makes sense.

Oh heck, let's put some steel up there. ;-)

maybe I'm not understanding how this swing is used.

sometimes less info is a good thing!

I don't like the idea of trying to thread a 6" eyebolt into the 1-1/2" edge of a joist.

I'd rather see you add blocking between two adjacent joists and then thread the eyebolt through the blocking. With your joists only being 2x6s, it'll spread the load from a single joist to two joists.

Another alternative would be to use a couple of roof anchors. They're designed for fall protection for roofers up on a roof. You can find them at the box stores, probably in the roofing area.

There are quite a few varieties of roof anchors, but this is the general type I'm referring to:

Use a keyhole saw to cut a small slit through the ceiling drywall right next to the ceiling joist. You can make the cut from the attic side of the ceiling drywall, with the saw blade held tight against the side of the joist.

Standing in your closet, slide the anchor's strap through the slit in the drywall. Up in the attic, nail the strap off to the side of the joist with the provided nails, or screw it off with deck screws, NOT drywall screws.

Enjoy!

"There are quite a few varieties of roof anchors, but this is the general type I'm referring to: "

Wonder what the actual live load rating of that on is?

Do not forget you have to account for the type and grade of wood and the nail size.

LOL. I know what the swings are for. Most people put them...above their beds, and the eyebolt/ring is used to hold mosquito or decorative netting most of the time.

Here in Canada, drilling or any actions that significantly weaken a manufactured truss would result in a failed framing inspection. Rectification would usually involve sistering or similar. I've seen it done after a house was finished, still a stupid idea since, if it's critical, your roof could collapse. We do have to consider snow load where we are, for example.

I've seen HVAC people cut them, and (other)central vac installers. Neither were for good reason.

"I can't help but think we've over engineering this project"

Ya think??

Find the joists. Install an eyebolt that will carry the weight. If the joists don't line up then blocking is in order so you have something solid to attach to.

2 attachment points won't let it unscrew. If it's 1 point then maybe think about a thrubolt.

We're not holding up the world in load here.

A piece of 2x6 laid flat bridging over the top of two adjacent joists at each hanger location will support the swing hangers just fine. Nail the 2 x 6 into the top of the joists to prevent movement. This distributes the weight over two joists nearer their supported ends if the joists run with the length of the swing. If the joist direction is perpendicular to the length of the swing, the number of supporting joists is four.

like hanging a heavy punching bag in the basement.

A couple of weeks into the project and we've yet to hear from the OP on its status. Is the swing everything it was promised to be. ;-)