Floating deck - Levelling footings

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Old 01-22-20, 08:11 PM
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Floating deck - Levelling footings

Hi all.

Im going to be putting together a floating deck.

Not to big, its about 3 meters x 4 meters.

Its going to be over sand.

Can i ask some tips on getting the sand level for the footings and also how to get them all the same height?
 
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Old 01-22-20, 08:28 PM
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This is a USA based site, and generally speaking, decks here cannot be "floating", they must be on footings that have been dug down below the local maximum frost depth.

But for decks that ARE built on grade (in backwater areas with no inspections or code enforcement) premade concrete deck blocks are often used as the "foundation" for the deck. As for leveling the sand, you would use a level and a screed. (A long board used to scrape the sand, which 2 people slide back and forth in a sawing motion). Screed it in multiple directions... checking to see which area is high, which area is low, and which direction you need to pull sand toward- or away from. Place the level on top of the long board to get a more accurate reading of your grade... or to compare how level it is from one deck block to another.

For what it's worth sand is not the best thing to build on. (Interestingly, compare Jesus' illustration in his Sermon on the Mount at Matt 7:26,27)

A base of crushed rock that has been compacted along with 3/4 minus (including fines) would provide the best base with the added benefit of proper drainage.
 
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Old 01-22-20, 09:52 PM
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Thanks for the info.

Here in Perth there isn't any frost so im assuming thats ok.

Is it better to pour concrete into a hole and use that as a foundation?

Im not planning on having the frame sat directly on the sand.

Im trying to find the best way to do the "legs" or foundation for the frame.

Any tips appreciated.

Thanks.
 
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Old 01-22-20, 10:00 PM
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When frost is not a concern, the main thing is putting your deck blocks on soil that is undisturbed... or that is likely to remain undisturbed. Just resting it on the ground opens up the possibility of soft ground that will shift or compact, making your deck sag over time, or putting it on soil that might wash away (erode) over time.

Often, that will mean digging down a bit, into soil that is more stable. In areas of the US where there is no frost, they still recommend digging down 6" or so for stability. Whether or not you want to make your own footing, or use a premade concrete deck block is totally up to you. In my opinion, pouring a footing that you can then drill into and put an actual post anchor into makes more sense.

If you want to get some good ideas of how attached decks are built here, google dca 6 deck guide. It's a free download and its well illustrated. Maybe it will give you some ideas you can modify for your build.
 
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Old 01-27-20, 04:56 PM
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Thanks.

Ill have a look at that dca guide.

Yes i like the idea of pouring and drilling - Sounds like it may be easier to adjust and get level.

Someone suggested as its a small build, building a frame attaching the posts - having the frame sitting on top of something - Getting it level - Having the posts dangling in holes and then filling in the holes.

Sound like it makes sense?
 
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Old 01-27-20, 08:56 PM
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With a few exceptions, it's almost never a good idea to embed wood in concrete. So while that would work, it's not the best for multiple reasons.

Why do you think it will be so hard to pour and level a few footings? Cardboard forms (one brand is called Sonotubes here) make it easy. Just cut them to the height you want with a skilsaw and arrange them around the site.
 
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Old 01-28-20, 09:30 PM
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They wouldn't be wood - I have seen metal decking legs (probably not what they are actually called) that i was thinking of using.

Just looking at the options available.

With the cardboard forms:
Do you just arrange them where you want them.
Get them level and then just pout the concrete to the top of each one?

That sounds easy.

Dont know why but getting things level just seems like the trickiest bit.
Im sure once i start it wont be as hard as it may seem.

Thanks again.
 
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Old 01-28-20, 09:47 PM
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Do you just arrange them where you want them.
Get them level and then just pout the concrete to the top of each one?
Yep, that's pretty much it. You just need to know where your posts will be, get the forms parallel, square and level.
 
 

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