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Old 04-22-2012, 10:19 AM   #1
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Sizing deck joist


I know deck codes are different for each area so maybe somebody from Manitoba is on here who can help me.

I am building a 14x14 deck which will be attached to the house and roughly 18" of the ground. My plan is to use 10" sono tubes(unless I could use 8" tubes) and 2x8 framing on 16" centres with 5/4x16 deck boards to finish it off.

The piers will be roughly 6.5' apart and I plan on using 6 piers. I am trying to figure out what size framing to use. I have a pamphlet from the city and how I am reading it, it sounds like I could get away with 2x6 joist. Would it be a huge waste of money just to do it all in 2x8 even if it is above code. I don't really want to spend the extra money if it will give me no benefit. If in the end it will help give me a stronger more secure deck I have no problem using 2x8.

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Old 04-22-2012, 10:24 AM   #2
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Sizing deck joist


Quote:
Originally Posted by darren
I know deck codes are different for each area so maybe somebody from Manitoba is on here who can help me.

I am building a 14x14 deck which will be attached to the house and roughly 18" of the ground. My plan is to use 10" sono tubes(unless I could use 8" tubes) and 2x8 framing on 16" centres with 5/4x16 deck boards to finish it off.

The piers will be roughly 6.5' apart and I plan on using 6 piers. I am trying to figure out what size framing to use. I have a pamphlet from the city and how I am reading it, it sounds like I could get away with 2x6 joist. Would it be a huge waste of money just to do it all in 2x8 even if it is above code. I don't really want to spend the extra money if it will give me no benefit. If in the end it will help give me a stronger more secure deck I have no problem using 2x8.
Your not spanning 14' with 2x6's.

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Old 04-22-2012, 10:44 AM   #3
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Sizing deck joist


Joe that brings up another question I had, when there talking about maximum span for joist; is it the total width of the deck(14' or so) or would that be ledger to first beam(6.5') and then between first beam and second beam(6.5').

My pamphlet says
Joist Size Maximum Span
2x4 6'10
2x6 10'9
2x8 14'2

So is the maximum the total width of the deck or would that be the maximum you could have between ledger and beam and beam to beam.
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Old 04-22-2012, 01:01 PM   #4
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Sizing deck joist


2x6 should never be considered for deck floor joists. My State's codes do not even have a section for 2x6 anything in regards to joists, 2x8 and up only.
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Old 04-22-2012, 01:27 PM   #5
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Sizing deck joist


Certainly you are on Canadian code, so it is difficult to compare with U.S. code. However, the span always refers to the unsupported length of the joist. In some codes, span is measured from the center line of the supports, in other cases it is measured from the edge of the supports, but in your case the span is about 6-1/2 feet based on the beam locations you quoted.

As noted by previous poster, IRC (International Residential Code) specifies a minimum of 2x8 joists, which for the weakest wood listed would span up to 8'4" for joists 16 inches on center. Apparently your code is different. You may want to check in with your building inspector to make sure they do not have a different interpretation of the code from you.
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Old 04-22-2012, 01:41 PM   #6
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Sizing deck joist


Quote:
Originally Posted by Daniel Holzman View Post
Certainly you are on Canadian code, so it is difficult to compare with U.S. code. However, the span always refers to the unsupported length of the joist. In some codes, span is measured from the center line of the supports, in other cases it is measured from the edge of the supports, but in your case the span is about 6-1/2 feet based on the beam locations you quoted.

As noted by previous poster, IRC (International Residential Code) specifies a minimum of 2x8 joists, which for the weakest wood listed would span up to 8'4" for joists 16 inches on center. Apparently your code is different. You may want to check in with your building inspector to make sure they do not have a different interpretation of the code from you.
Thanks for the help, guess I will stick with 2x8 for the framing.
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Old 04-22-2012, 07:08 PM   #7
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Sizing deck joist


im on the east coast of canada, 2x8's are teh minimum allowed for a deck joist. 2x4's are only used for handrail and framing in skirting under the deck..

the odd time an inspector will allow 2x6 joists is for a deck thats no more than 4' and thats usually just for a small porch off a side entry door

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