I would rather not dig holes and pour footings to below the frost line (Toronto, Canada), more due to hitting tree roots than laziness. Are the Dek-block piers for floating decks ok? Just on the ground or put some compacted crusher-run under them?
We put a 400 gallon hot-tub on patio stones sitting on a compacted gravel pad (on advice of our dealer who recommended not to pour a concrete pad) in 1995 and it hasn’t moved at all. The deck would be against the hot-tub.
The deck would be 2 levels of 8″ and 16″ (1 and 2 steps up) on ground that seems to drain well. The deck would not be attached to the house, so it can float, although I would prefer not to have frost heave issues.
Any advice appreciated.
Thank you!
…karl
Replies
Pier blocks should be fine but you should dig a hole at least 2'x2'x8"deep and put one bag of premix concrete in the hole then a pier block, then another bag around that.
This makes for a nice wide footing.
If you have tree roots you deck is going to lift no matter what you do.
I don't know what your ground is like around there but ours is like concrete here in the Seattle area.
"Rather be a hammer than a nail"
Bob
Bob,
when you say put in one bag of premix, then the block, and another bag around it.....
Are you mixing the crete or pouring it in dry?
Thanks,
BrianView Image
You do it dry. You can add water after you are done. The concrete will pull moisture out of the ground and set up weather you add water or not, but we add water to make the top look smooth."Rather be a hammer than a nail"
Bob
Bob, this will be one of those times I will respectfully disagree with you.
Toronto is subject to frost heaves like New York. I'm sure that a deck there is subject to code, irrespective of the hot-tub dealer's advice (which may have been foolish, illegal and may have placed his company on the wrong end of a lawsuit).
This good homeowner should really be speaking to his city hall building department.
Sorry, Pro.Quality repairs for your home.
Aaron the HandymanVancouver, Canada
Regarding the hottub, normally a hottub is placed on a concrete pad that is poured on a compacted gravel base. Think floating slab.
I was advised to replace the concrete pad with some patio tiles (the 2'x2' ones). The reasoning was:
- both the concrete slab and the stones are floating, so both can have frost heave. I haven't heard of anybody pouring deep footings in for a hottub/spa that sits directly on the ground.
- if you have frost heave, you can always empty the tub, tilt it up (with some help) and relevel the stones. You can't really relevel a concrete slab. This made sense to me.
Since 1995, no movement at all. The soil does have good drainage (after about 2 or 3' of topsoil, it's all sand below) which is a prime factor here in keeping stuff dry. The base is about 6" of compacted 3/4" crusher run and 2" of compacted screening, with the patio stones set into the screening.
I have not seen any specific directions regarding the need for anything else from the City of Toronto building department. I believe I did check back then. I actually just called again and so far the answer is that there is no answer, but I am awaiting a further callback.
Regarding the Dek-blocks, is a (shallow) footing around them really needed? I can see that it would distribute load more, but according to the manufacturer, if you space them according to their plans, you don't need a footing.
...kurious karl
Aaron, I am confused as to what you are disagreeing with me on? The customer has a hot tub sitting on a gravel base, it is done all the time here. Now the customer wants to get into the tub by walking across a ground level deck. The customer does not want to dig and was asking if he could put the piers on the ground.
I'm suggesting NO because when people just set a pier block on sod it compresses and makes for an uneven deck. I suggested he go at least 8" deep. I realize the ground moves back East but I doubt it moves as much as this enclosed picture.
The ideal situation to compensate for all the ground movement would be self leveling pier blocks that would adjust themselves.In some cases they need to travel too. They would probably not be affordable.
Are you suggesting that this ground level deck should be setting on sono tubes dug down 4 to 5' ? Or that a building department will give this home owner better advise on how to put a hot tub on the ground?
It's OK to disagree with me, you have your opinion I have mine. Please tell me what exactly are we not in agreement on.
"Rather be a hammer than a nail"
Bob
Edited 9/18/2003 3:25:36 PM ET by Pro-Dek
I assume you read the response to me by the homeowner.
My response was because of my own house, where an addition was done in the late '70s, before I got back from South Africa. The builder put up piers to support the kitchen extension and the very small deck. From the day the thing was finished, the extension has been sinking, and this with bases of 24x24x8" deep.
I know you suggested 8"
Soil conditions here are different here than in Seattle area. In Toronto, the frost is more extreme yet. The homeowner had a gravel pad and deck blocks for a 400 gallon hot tub and I just think he needs a deeper base for a relatively light PSF loading to keep it stable.
Only my opinion. You' the man!Quality repairs for your home.
Aaron the HandymanVancouver, Canada
I'm in MA so I have the same type frost issue as NY (maybe not as bad as the Buffalo area etc.). If this is just a ground level deck about 1' off the ground I think Pro-Dek's wide footed piers would be the way to go. To me it is like a shed floor, it isn't like you are going to dig 48" footings for a shed normally. You put them on pier blocks or cinder blocks. If the deck was going to be a significant height off the ground like one story etc. I would obviously go with the footings dug below the frost line.
But hey to each his own.Know a little about alot and alot about little.
Is this what you are worried about?