Free standing deck and attaching to house


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Old 04-05-10, 01:09 PM
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Free standing deck and attaching to house

Hi everyone,
I've picked up a lot of useful info here on materials and design as we prepare to take out the original concrete slab entranceway to our home (improperly supported on one resulting in cracking of whole slab as it sinks... another story!) and replace with a 8' High, 22' Wide by 10' Depth.

Based on reading here, free standing with 6" pressure-treated post supports all around the perimeter on concrete-piers seemed the most strong in conjunction with PT 2"x8" joists.
One question has arisen - what is the optimal attachment to the house itself to prevent deck-sway? One contractor has suggested lag-bolts through the concrete block every 16"-24" but that was for a ledger-type deck construction where the ledger-board was fastened to the foundation.
Are the recommendations for 'free-standing' deck foundation that perhaps don't require so many (across a 22' span) holes through the foundation?
thanks,
Greynold99
 
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Old 04-05-10, 02:52 PM
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If you have any frost in the winter you can not attach a deck to a house unless you install frost footings. What is your location?
 
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Old 04-06-10, 04:50 AM
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The deck would not sway unless the piers were sinking and if that were the case it would pull away from your house if you bolted it on. Free standing is fine.
 
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Old 04-06-10, 09:59 PM
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Bolt braces at 45 degree angles from the support posts that are "attached" to the concrete piers up to the floor jousts. At least half way down the height of the support post (the longer the better) and in both directions. No need to attach anything to the house.
 
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Old 04-07-10, 04:37 AM
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At 8' high (assuming that is the highest point) you could use 4X6 posts, or even 4X4's that were properly cross-braced. That would allow you to use 4X beams rather than 6X's.

Free-standing will eliminate the ledger, and all of the issues with getting it properly attached and flashed.

It's been years since I built an attached deck. Free-standing is an extra row of posts and footings and an extra beam, but is sure eliminates a lot of problems.
 
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Old 04-16-10, 07:04 AM
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Appreciate your replies

Thanks for responding to all. I had not even considered attaching deck to house with a 'free-standing' deck, but a contractor whose main experience had been with 'ledger-type' deck construction as I found out was suggesting it. Turns out the building codes for where he had worked building commercial housing multi-units were very stringent on how this type of contruction was done.

Though more expensive, I do like the type of look and structural strength you get with 6"X6" PT posts, notched-on-the top to accept the outside-perimeter 2"X8" framing boards fastened with carriage-bolts.

Greynold99
 
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Old 04-16-10, 04:40 PM
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You better believe that the building codes are stringent!! There have been too many instances of deck ledgers failing, leading to the deaths of people. (And SAFETY is what the codes are all about!!)

Freestanding -- no ledger to fail -- no collapsed decks -- nobody gets hurt or killed. Granted, freestanding won't last forever, but then NO DECK WILL. At least a freestanding deck, WHEN it starts to fail, will usually do that with some warning. (If it gets 'wobbly', DO NOT load a hundred of your closest friends on it!!)
 
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Old 04-18-10, 09:06 AM
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Using single 2X8's as the beams isn't an option. You need to double them, or even triple them, depending on what you use for posts. double 2X8's would allow you to notch a 6X6 post and rest the 2X8's in the notch. Thru-bolt the connection. Using double 2X8's will limit your post spacing to about 8', depending on the species of 2X8's.
 
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Old 04-19-10, 06:47 AM
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Reply to Lefty...

Thanks Lefty,

Are you able to provide a graphic/picture of what you're describing or perhaps a reference link to something similar.

The way I'm envisioning your description, you could either bolt two 2"X8" beams together and notch the 6"X6" post 3" to accept them or, notch an 1 1/2" on both front & back of the 6"X6", and 'sandwich' a 3rd 2"X8" in between the other 2 - either notching the 6"X6" on side or using a Simpson galv hanger...
For a 10' deck depth... which do you suggest?
greynold99
 
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Old 04-19-10, 08:21 AM
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First, the DEPTH of the deck really has nothing to do with the beam size. The beam size is determined by the post spacing under the beam. The larger the beam, the farther it will span, so the farther you can spce the posts.

DEPTH will determine your joist size and spacing. (Your decking material will limit the joist spacing.)

Dbl 2X8's and notch the post 3" to accept them, or triple 2X8's and use the Simpson BC on top of the post.
 
 

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