How to support a deck?

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ripp6957

New member
I want to build a 15'X20' deck off our house in Munising, MI. It will be 'floating', i.e., unattached to the house and about 12" above the ground. My question is, how should I set the supports? Will setting 4x4's on the concrete, above ground anchors be OK, or would you recommend sinking the wood in footers? About how deep? I think you go below the frost line, which would be about 3' in that area. Any input will be appreciated!
Thanks, mark the fireman
 
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tyeeman

New member
I'm by no means a builder but I did build my deck, only difference is mine is attached to the house. Any way, wouldn't local code dictate how the deck should be built? If not, if I were doing it I would put in footings below the frost line and anchor the 4 X 4' or 6 X 6s (I think bigger is better) into the concrete. That way when you have a bunch of people line dancing or what ever on your deck it would feel fairly solid.
Why don't you want to anchor it to your house? That would really make it solid. Unless your deck will be a number of feet away from your house......
 
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scott_l

Member
I am not a builder as well and I have no idea what your local could specifies (I believe in MN as long as it is not attached to the house you don't need to pull a permit).

They sell concrete "stands" that are about 12"x12"x10" and that have groves preformed into them (the groves are there so your stringers have a place to rest). These "concrete stands" are made for exactly what you are talking about. You place them on the ground (I don't know how far apart they are supposed to be) level them and then start building your deck.

I personally see no reason to put footings in if you are not anchoring it to your house.
 
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98panther

New member
A floating deck actually means - there are no frost footings.
it's floating on the ground, frost can move it.

Not attached to the house and 24" or less from the ground, that would be legal here.
 
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anonomoose

New member
Nothing wrong with not attaching it, probably less headache over time.

Point of the cement is not to prevent wobble, but to provide support and prevent the post from sinking. The post wobble is prevented by the number of posts and side support of the hole the posts sit in. Go deeper if you are in doubt about wobble. Cement in the holes should be thick enough to prevent the post from settling down...so you don't have to go wild with cement costs. Pour the cement, let it set up and drop in the post and backfill it.

A deck that size will have lots of holes and lots of support and even if you ever do a line dance it won't go anywhere.

Long term, you would ideally like to have the cement at least level so that it does not CUP and hold moisture. Make sure you are well below frost line tho, and I suspect that code in that area is more than 42 inches. Even if it isn't I would go 48 or 50...just because. Built it right and it will last longer than you will.
 
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ezra

Well-known member
42 in holes belled out at bottom would be the correct depth in most cold areas. and I would not sink my posts in to the footing more susceptible to rot sitting in concrete.poor your footing and drop in bolt so you can attach the steel post holder that keeps post off ground.
you stop sway buy 1st using sway brace on under side of deck then a sway on at least 2 sides.
the diff between 4x4 and 6x6 is minn I would prob just use 4x4 .
I assume you are going 12 ft for a few reasons but 1 is prob storage so I would lay it out so you have the center posts at the 10 foot point you are looking at prob 9 footings.
I would use 20ft 2x12 beam on far end 2x10 beam for center and double or triple rim joust on far end lagged to posts.
now unerside has pre built in angel you can screw poll barn steel to and drain watter away from stored stuff unerd deack .
not a deck expert but I do do 2 to 4 decks a yr
 
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mtb1115

New member
The pre-cast support blocks work well, they can be leveled by setting them on a small pad of concrete, sono tubes with the metal anchor plates are the best. Another option is to pour a patio, at 5" thick your only looking at about 5 yards (Chicagoland price is about $ 105.00 yd). You can frame it up in any shape, coloring and stamping can add a lot to the price but plain concrete is maintenance free and you won't have to worry about critters making a home under it and you being a fireman I'm sure you can find a few guy's to help for a reasonable price.
 
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ezra

Well-known member
sorry my bad re read guess you said 12in not 12ft thought you were doing a 2nd floor deck.
so then yeah precast footings on 16in pavers would work fine.
or yeah just pour a slab way less maintenance ez to pour screed and broom done 4 ever.
if you want 12 in off ground just use cheep Masonite 12 in siding to forum and nice thing about Masonite you can free forum curves and what not.
fill center of forum with sand and sides no sand you have a 12 in tall floating slab with a 4in pour in center.
you can also just toss dry powder dye over top when wet with out stamping for a more stone look with out the stamping or just order a solid color from plant
 
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racerx

Active member
I did not attach mine to the house for two reasons, it was less than 24" of the ground and my 1st floor house deck is TGI (TJI Truss Joist I-Beam) which the deck would be on "ends" and on the ends of the TGI is just some crappy OSB cap, so lag bolting in a 2x10 ledger to OSB just seemed like a waste no strength whatsoever IMO. Plus I did not have to mess with the siding or seal up to avoid water intrusion.

I went with a solid footing below the frost line with a bolt in the top for 4x4 post bracket which lifts the post off the concrete an inch or so.
 
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baken

New member
I used to work for a builder that specialized in decks, and in southern Wisconsin most codes are a four foot deep footing. Leave them all open for the inspector if your going that route. We always put about 8 inches of dry concrete mix in the bottom of the hole and then tamped it down with the post until it was firm, plumbed it up and then pour another bag of dry mix in fill it up slowly with dirt tamping all the while and checking plumb. I totally agree with not attatching it to the house on a lower level application just to stay away from water leakage and extra work with messing with siding and flashing. Make sure to use stainless or dipped galvanized hardware others will not last in the newer treated lumber.
 
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700classic

New member
You are there for it no matter what decisions it makes in life. When things go bad you're there with a shoulder to cry and to pick it up and dust it off, tell it everything will be okay. Let it know you have its back when things are down.;)
 
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freezinbevr

New member
Both of my decks are not attached to the house, same height from the ground (12 inches) and very stable. 10 years old, composite decking, pressure wash off every year or two for "stuff" that accumulates. A patio is the most permanent, but choices are tied into taste and budgets.

The only thing I would do different is build it bigger. Found a great vid on helping to go with a bigger deck!! :)

http://www.youtube.com/watch?v=QQ7Ue5emo6I

Brad
 
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ripp6957

New member
Thanks for all the good info. I'm going to build it about 8' from the house so I don't have to fool with attaching it. As far as getting other fireman to help, all my buddies are 1700 + mi away!
 
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ezra

Well-known member
you can build it tight to house and still not attach.my deck is less than 2 in from house unattached.
I did my own deck un attached because in my area if less than 47in off ground and not attached you need no permit. and no permit means no letter from city to the state tax adjuster who seams to show up no more than 7 days after closing permits around my parts.
 
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