advice for reinforcing 2x4 joist for porch swing


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Old 05-13-17, 06:46 AM
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advice for reinforcing 2x4 joist for porch swing

Hello All,

Willing novice here looking for some suggestions. I'm working on installing a 5' porch swing - safely I removed a few pieces of the vinyl siding porch ceiling and unfortunately discovered that the joists are 2x4 lengths (was hoping of course for 2 x 8). Joists are 8' long perpendicular to the house and are at 22" centers. There are also horizontal 2x4s at 24" centers that run perpendicular to the bottom side of the joists over the entire length of the porch. Ends of each joist are nailed into horizontal 2x8s beams at either side of the porch (house side and garden side). Rafters are then attached using screws and metal plating to the joist ends.

My plan is to attach the porch swing to a single joist (that is, the swing's 5' length is parallel to the joists). Since joist is not 2x8, I know I need to reinforce it. My thinking is to sister existing 2x4 joist on both sides with additional 2x4 8'lengths using glue and screws (or carriage bolts?). I may be able to sister 2x6s instead of 2x4s, but there is limited vertical space at the one end of the joist because of the roof angle, so it will be a tight squeeze. If I use the 2x6s, do I use them as the attachment points for the swing?

Hope this doesn't sound too naive - any advice from the experts here much appreciated!
 
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Old 05-13-17, 06:58 AM
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Sistering with 2x6s is reasonable. If you need to taper the top edge at one side to fit under the roof, that will not seriously impact the strength. Construction adhesive and construction type screws (not drywall screws, but GRK or SPAX type) will be fine. I favor a lot of screws over a few carriage bolts. Use screws long enough to penetrate all three layers and screw from both sides.
 
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Old 05-13-17, 07:43 AM
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Wow, thanks for such a quick response. This forum is great, wish I had discovered it years ago. Excellent. I assume I should sandwich the existing 2x4 between the 2x6's? Should I use one of the 2 x 6 for the mounting points for the porch swing or maybe it does't matter from a structural strength standpoint? One last question - should the ends of the sister joists also be nailed (or hangered) into the same ends (house and garden facing beams of the patio) as the existing joist or does it not really matter.

Thanks!
 
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Old 05-13-17, 07:58 AM
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Swing Support

Wow! That will be a huge amount of support, considering that the attachment for the swing suspension will only be 18 inches or less from the ends of the joists.

I would attach suspension to the original 2x4. That way, the attachment will be in the center of the 2x4,2x6's combined joist.
 
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Old 05-13-17, 08:16 AM
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Well, I think that is the good kind of 'Wow'

Original 2x4 attachment it is, hope to get working on this today. Appreciate the peace of mind you guys just provided me with on this project.
 
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Old 05-14-17, 04:29 AM
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Yes secure the sisters to the end supports as well as the existing 2x4. Simson StrongTie makes EXCELLENT structural screws - use glue also.

If you can fit it in, albeit cutting the ends to make them fit, IMO 2x8s are better sisters than the 2x6. That extra vertical depth is a lot stronger. You can notch / carve the ends as needed to make them fit to your application.
 
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Old 05-15-17, 04:04 AM
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Thanks - well I went the 2x6 route. Worst part by far was getting the lumber up into the ceiling, like fitting a jigsaw puzzle due to the narrow clearances and all the rafters. Not sure I could have fit 2 x 8s so hopefully this will be sufficient.

Got the 2x6s sandwiched around the 2x4 and put up additional blocking to cover the gap between the bottom of the joist and vinyl ceiling where the mounting points for the swing will be. Thanks for the suggestion about the end-supports too, will look into that before I put in the mounting hardware and close up the rest of the ceiling. Just not enough time in the day!
 
 

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