Questions tagged [span-tables]

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Can a 2x4 span 14' in a greenhouse roof?

I have seven 24 x 13.302 glass panels that I want to use to build a greenhouse. I also have a lot of 2x4x14s and 2x4x8s that I can use. I would like for the greenhouse to be as close to 14x14 as I can ...
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0 answers
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What is proper beam size for 10'-8" spans between columns?

I am constructing a 22'-0" x 32'-0" carport, using pre-fab trusses to span the 22' width. The distance between columns is 10'-8" O.C. Will using three 2x12 yellow pine, with 2 layers of ...
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1 answer
85 views

Calculating center beam for purlins on porch roof

I'm building a porch roof as seen in the picture below. The blue boards will be 2x6x12 on 24" centers. Knowing this, how do I determine the size of the red boards? I do plan on doubling each red ...
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-1 votes
1 answer
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Can I span 36” with SYP 2x4 laying flat as roof decking

I’m redoing my garage roof, which has a 12” slope over 14’. I have left over SYP 2x4’s and some microlam beams, but only enough to set at 36” OC. Can I span 36” with 2x4 SYP as my decking instead of ...
1 vote
2 answers
141 views

Existing joists span max 17.5in OC - Trex composite says max 16" allowed

Does anyone have experience with pushing the limits of joist span for composite decking? My joists are generally 16" OC but a few gaps are up to 17.5" max (one has a short section at 18"...
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1 vote
1 answer
954 views

Header size for enlarged opening...am I reading this correctly?

I'm enlarging an opening for a front door. I'm trying to work out the header size. Please see attached picture for reference. Structure: As the structure of my house doesn't match what is in the code ...
0 votes
1 answer
564 views

Can you use three 2x8 sandwiched with 1/2" plywood between to get a 16' header

Header to supporting the roof and rafters. It was a patio converted to a sun room and I would like to replace two large windows with a sliding door. Currently 4x10x12 header with post in middle. ...
1 vote
0 answers
244 views

Will a 4x8 swingset beam with 4x6 notches at either end support a 16 foot span?

Non-engineer here, I'm trying to adapt a typical "A-frame swingset design" (like this https://www.instructables.com/id/Free-standing-A-Frame-Swing-Set/) to be a small set of traveling rings ...
1 vote
2 answers
3k views

What lower-profile options do I have to replace a triple 2x12 beam?

I am removing a center post on my patio cover to create a clear span of 15'. The current beam is 2 2x8s with three 4x4 posts. I have had a engineer friend calculate the load for the roof (pic attached)...
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0 votes
1 answer
227 views

Can someone help me to verify if my balcony can handle the load of a hot tub

I would like to place a hot tub on my balcony, and need help to double check if my floor joist can handle the load. I have have 2 x 12 floor joist @ 16" o.c. with 3/4" plywood decking and 1/2" ...
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0 answers
437 views

Can I use scaffold boards butted side by side instead of rafters for a flat roof?

The thickness of a scaffold board is 35mm and so laying the boards side by side (just like you would see on scaffolding) instead of using 4 by 2's will create an extra 60mm of much needed headroom ...
-1 votes
1 answer
460 views

Floating Dock Framing Length?

I'm planning on building a floating dock and am looking for advice on framing. More Specifically, i'm wondering if anyone knows what the maximum length I can span between two floats? I inherited ...
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1 vote
1 answer
4k views

Strengthening existing 2x4 joists to create a mini attic

Between the first and second floor of a friend's house he has about 4' of dead space between floors that he wants me to help convert into storage (this is in San Francisco, so every square foot counts!...
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1 vote
1 answer
546 views

Can I Notch a Double 2x12 Floor Joist Down to 2x6 Size (5.5 inches) if I need a 2x8 (7.25) per My Local Span Table

I have a 12' span with a floor joist that is currently 2 2x12's. It was originally a 16'+ span with an attic opening that was 3' wide thus the reason for the double 2x12's. I'm installing an L ...
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1 vote
1 answer
920 views

joist bridge for hanging porch seating

Want to build and hang a "bed/sofa" 64Lx32W on PT deck w/PT 7x2x10' rafters 16"oc. Spacing of rafters wrong for hanging. I can cut down size of the seating, but it defeats objective. QUESTION: can ...
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1 vote
1 answer
8k views

ceiling joist allowable span southern california

I'm adding ceiling joists in my garage. It's a 19' span between walls, and I'm using structural or #1 lumber. Should I use 2x8x22 OR 2X10X22 spaced 12" on center? I'll be adding 1/2" or 5/8" drywall.
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0 votes
3 answers
2k views

maximum ceiling joist to beam span without joist hangers

I'm building a tray ceiling and the assembly is easy to visualize. In a 14' x 14' dining room, I'm coming in 18.5" to the inside of the beam on 2 sides with a 2x10, and then similarly cross-wise ...
0 votes
1 answer
111 views

Allowable load tables based on usage

When looking at allowable load tables from Simpson for their joist hangers, why are there different numbers for different cases, even though the force is in the same direction? For example, the LUS24 ...
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0 votes
1 answer
287 views

6 x 12 header capability

I need to support a ridge beam on one end with a Douglas fir 6 x 12 x 12 ft long header. The load will be on a single point in the center and will be about 8000 lbs total. I can't tolerate sag as ...
0 votes
3 answers
4k views

How much shear load can rebar withstand?

I'm thinking of integrating rebar into a short grape trellis as horizontal supports for the vines to climb on. Is there anywhere I can get the deflection/load information for rebar spans? As currently ...
1 vote
2 answers
5k views

Span of roof rafters, how to fix improper structure

I'm building a carport that is 30x24 ft including a 20x24 gable and 10x24 lean to. It currently has 2x4 roof rafters spaced 24" with collar ties about a foot below the gable peak, so 5-6 ft long ties. ...
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0 votes
2 answers
9k views

Can I calculate beam size if I know length, and weight support requirements?

I am interested in hanging a heavy-bag/swing/aerial yoga bands - but am concerned about hanging from a strong enough beam. I have tried to read lots about deflections of different material based on ...
0 votes
1 answer
27k views

Will 2x10 13'6" span support outdoor bbq?

I am building a deck and will have 2x10 joists. I want to put a BBQ that unfortunately will run parallel with the joists, so the last two joists will support the full weight of the BBQ distributed ...
0 votes
1 answer
2k views

Pergola span 2x6x16

I've been thinking about putting a pergola in my back yard using 4x6 post mounted on top of a cement slab. I want it to be 8ftx16ft. I want to use 3 post in the rear of the pergola, and just 2 in the ...
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0 votes
1 answer
7k views

Can a 2x6 beam span 11ft?

I need to span a beam 11' between two 6x6 posts to support the rafters for a covered pergola. I was thinking of fastening 3 pieces of 2x6 together to create a stronger piece. Is it possible? Is there ...
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2 votes
4 answers
3k views

Acceptable joist depth for a second set of ceiling-only joists

Background I'm installing a new ceiling in the kitchen of the bottom unit of a multi-family home. The house is quite old and uses 2x8 (actually 2"x7.5", not 1.5"x7.5", due to era of lumber) over a ...
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1 vote
2 answers
2k views

Understanding deck spans for beams.

I've been looking at various span charts for decks and I'm still not quite sure how to calculate it all when you take into account not just the joists, but the beams and posts as well. What we ...
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0 votes
1 answer
2k views

2x6 deck joists: salvageable or need replacing?

We have a roughly 10x30 elevated wood deck off the pack of our house. The joists are all 2x6 16oc. The posts are 4x4 and are holding up a beam that the joists hang off of with joist hangers. I feel ...
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1 vote
1 answer
22k views

How far apart should I space rafters for a 13ft patio?

I'm looking to build a patio roof (shed style) and need to span 13ft. I've found several span tables online, some of them with different maximum distances between the rafters. Is it ok to use 2x8s ...
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6 votes
5 answers
24k views

Can I use the area above my garage for storage?

The ceiling joists in my garage are 2x8 spaced 24" o.c., and span 21'. The roof load appears to be carried by the walls, so the joists seem to only be in place to hold the drywall. I'd like to use ...
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