Footings or Not?

[Tom_From_NJ]

I want to add a canopy/roof, about 7 feet wide by 12 feet long to my shed, which is about 12 feet wide by 24 feet long, to store stuff out of the weather. The shed sits on about a foot of gravel that was mixed with fines and is compacted. The floor is six pressure treated 4 by 4 with ¾ plywood floor. My question is the two or three posts I will put in to hold up the end NOT connected to the shed, do I dig down 3 feet below the frost line and put the posts in the ground or just sit it on a concrete block? I have dug down a foot and will back fill with the same material as the shed is sitting on. The block will sit on the compacted stone. The connection to the shed will be a 2 by 6 nailed to the outside of the shed wall, with 2 by 6 2 feet on center. I figure if the shed moves with the frost then the canopy will also. What do you think? Footings or a block?

[Fawteen]

Block, definitely. If you put in footings, the shed will move relative to the addition, and you'll have problems. You want the whole thing to float.

[Gary_in_Indiana]

I agree. You don't want either part moving independently of the other.

[tdenny]

Use the blocks - they also can be easily adjusted if something floats too badly.

[pbenven]

We did kind of like both on a deck up at my parent's old country place.

We dug 20" x 20" holes below the frost line, put in some forms that protruded about 6" above grade and poured the concrete. The deck posts just stand on these pillars.

The date on the picture is accurate and it still looks good today.

I always dig down at least four feet. Not as much as for frost but also for stability, esp. if you get high winds. Then put a concrete pad in the bottom and tamp it all down tight. I definitely would not just use a concrete block to sit them on.

[kconner]

does anyone think a 4-8 inch gravel or QP pad might be a good foundation ?

[beenthere]

QP pad? [img]/forums/images/icons/confused.gif[/img]

[johnday]

Tom; You've got to get below the frost or the whole thing will move. I don't think you want that.

The inspectors like the way I do it. And heres how. In your area the frost line is probably 36". Go down a minimum of 42". Dump an 80# bag of redimix in the hole. Add about 3 gallons of water. Use a piece of pipe or shovel handle to poke thru the concrete and the water will mix with it. This will pretty much self level. Wait around for at least a day. Put your posts in and plumb them, and backfill with the dirt you dug out. Dump in a few shovels full and tamp down with a 2x4, untill you reach grade. I build decks and polebarns this way. The inspectors in my area have even said that if everyone did it similarly, that the homeowners wouldn't have a problem with frost heave. If you just lay a block on the ground, your whole overhang will float and could even pull away from the original structure. Not a nice thing to have happen. PM me if you need to, no problem. [img]/forums/images/icons/smile.gif[/img]