Freestanding deck footers and attachment

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Old 06-19-16, 09:40 PM
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Freestanding deck footers and attachment

Hello all, I am planning on building a deck on the back of my single story 50's ranch in New Jersey. The deck will be quite low, being that it is a single story ranch on a level grade, however it will be reasonable large (35' wide x 15' deep). Initially my intention was to build a simple freestanding deck, however code dictates that the footings must be at the same depth as the house footings if within 5ft, i'm guessing to avoid disturbed earth. This may seem like a basic question, but I would like to be armed with some knowledge before I get this done, and deal with permits. Now, if the footings were setback the 5ft to avoid digging down so far, there would be left at the least a 5 ft cantilever past the beam to reach the house. If that rim joist was attached to the house, would it still be considered a "freestanding" deck, and is that a legitimate way to construct a deck? I guess my concern would be the deck causing damage to the house. Suggestions? Forgive me if I sound like an ammature
 
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Old 06-20-16, 04:14 AM
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Here is your deck building guide

http://www.awc.org/pdf/codes-standar...Guide-1405.pdf

Maximum cantilever is the length of the beams divided by 4. So, you will not get a full 5 feet out of that for your cantilever. Free standing means that, free standing - attaching it to the house makes it no longer free standing.

Keep in mind that low level decks often do not have enough drainage which causes moisture to stay trapped beneath. This results in early deck failure.
 
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Old 06-20-16, 04:18 AM
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Also, in some communities if attached to house, it may be considered an improvement and subject to re-assessment.
 
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Old 06-20-16, 04:56 AM
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Also in your area I'd want that decking about 6" below the threshold to prevent water and snow from becoming an issue.
 
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Old 06-20-16, 07:09 PM
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Am I correct in saying that if the maximum cantilever is L/4, and the footing distance from the house is 5ft, than in order to maintain both of those codes, the beam would need to be 20ft long? Am I calculating this wrong?
 
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Old 06-20-16, 07:56 PM
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No, you are calculating it right and getting 20ft long PT beams isn't going to happen. So you are going to have to dig deep near the house. Best to check with the local code office to be correct in your size and depth of the footers in that area.
 
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Old 06-20-16, 08:19 PM
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What's your aversion to a ledger? When properly done, it would cause no "damage to the house".
 
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Old 06-20-16, 10:31 PM
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My aversion initially was my fear of doing damage to the house if the deck were to shift. It's a 60 year old house and I didn't want to disturb it. Another reason was that I am not quite ready to redo the siding and in order to properly seal the ledger, the siding would need to be removed. The deck would only be 30" high and freestanding seems to be the easiest given its size.
 
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Old 06-21-16, 05:21 AM
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Thats crazy. What kind of siding?
 
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Old 06-28-16, 09:29 PM
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Thank you guys. I have ditched the freestanding design and have now begun CADing up plans for a deck with a ledger attachment. Given the 17' depth I am still doing 2 rows of footings for 2 beams to support the joists span. After reviewing the codes outlines in my area (new jersey), I have a few questions concerning details I cannot find. Thanks

-The footer cannot be within 5ft of the existing foundation unless dug to the same depth as the house footings. This is written a few times. however the only diagram I see, shows that dimension from the center of the footer to the edge of the house footer. These dimensions confuse me, as the purpose of this code is to avoid disturbed soil, why would the dimension be to the center of the deck footer and not the edge of the deck footer to the edge of the house footer. Do inspectors measure the distance from the pier to the house or do they wnt to know the true location of the house footer?

-My deck design is approximately 30" high, are there any minimum height requirements for the framing? I recall hearing 12" minimum above grade, however I cannot seem to find this in writing

-Is there a maximum coverage ratio as far as the decks size goes? Possible sqft limit. I think there is a depth to length ratio of 1:1 limit, but I cannot see anything about any other limits. The deck is 35'x17'x30"

-the code says you can subsitute an 8x8 as an alternative to the minimum 6x6 posts off the minimum 12" diameter pier. When using an 8x8 is it recommended to use a larger diameter pier?

Given the low height the deck, would there be any benefit to eliminating the post off the pier and just pouring a higher pier and connecting the beam directly?

Thanks guys, great forum

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