Support for Chainfall.

[GPintheMitten]

BTW, this leanto is already built. Probably about 25 years ago. It has plywood sheathing on the roof with a steel panel roof.

I can't add an additional rafters easily and can't build anything on top of the rafters.

I want to safely be able to lift a max of 1000 pounds with either a chainfall or an electric motorized cable hoist.

My research tells me that 1.25" schedule 40 pipe will be strong enough for a 24" span. I just need to determine an appropriate way to attach it and determine if some upgrade is needed for the rafters that I can afford and can do myself.

 

[Depmandog]

I would sister the rafter all the way - wall to wall, with 1/2 ply glued and screwed in between. Then I would repeat the same on the next rafter. Finally, I would install two rows of blocking the full length on the lean to. You wouldn't have to use 2x12 for the blocking, I wouldn't use less then 2x8.

The blocking will transfer the load onto adjacent rafters - past your pipe.

As a "safety", string a mason line taught wall to wall at the bottom edge of a rafter. Tap a nail in as a reference point into the rafter, under the mason line. When applying a load, keep you eye on the line. If the nail separates from the line more than say 1/2"-3/4", you have reached your "pucker factor load limit"

 

[radioman]

I agree - sister it all the way. if you dont- you are just adding more dead weight. blocking is a great idea - similar to building a beam to go across a few rafters.

 

[bcp]

you could get one of these, and use it other places when needed.

1 Ton Telescoping Gantry Crane



For reinforced wood beams, here is some good reading:
Structural Design in Wood - Judith J. Stalnaker, Ernest C. Harris - Google Books

Bruce

 

[GPintheMitten]

I would sister the rafter all the way - wall to wall, with 1/2 ply glued and screwed in between. Then I would repeat the same on the next rafter. Finally, I would install two rows of blocking the full length on the lean to. You wouldn't have to use 2x12 for the blocking, I wouldn't use less then 2x8.

The blocking will transfer the load onto adjacent rafters - past your pipe.

As a "safety", string a mason line taught wall to wall at the bottom edge of a rafter. Tap a nail in as a reference point into the rafter, under the mason line. When applying a load, keep you eye on the line. If the nail separates from the line more than say 1/2"-3/4", you have reached your "pucker factor load limit"

Ok, what you say makes sense. I'll do it the way you suggested. Thanks very much.