[ryan5068]

I have a question about pouring a concrete pad? I basically want to pour about an 8'x8' pad for a hot tub which will ultimately be under a deck. Is there anything extra that needs to be done to house a hot tub, any extra bracing. What is the procedure on prepping the surface to be poured onto. I can make the frame and such but how much earth do I need to remove before I put down the compacted surface and what surface do I put down to compact? Sand/Pea rock? I really don't know exactly how to do it but I hope with your help I can get it done.

 

[Avadon]

I too am interested in this response. I've always wanted to pour my own slabs but in my opinion it may be better to bring in someone to help you with the prep. I've seen contractors dig down a 6-8"(maybe deeper) and than tamp tamp tamp, even sometimes using a vibrating machine to compact the earth. Than pea gravel, forms, rebar, etc. than pouring, saw cut lines, than concrete densifier (liquid hard ultra) and (belltraix) from WR meadows. There are good books on how to creating floating slabs like this. Also you got to plan for water and drainage as well as electrical. This is a fairly advanced project. (worried face)

 

[ryan5068]

WEll I am certainly up for the challenge. I have some friends that are in the concrete business so getting ahold of one of them for the day would not be too much of a challenge. I just wanted to know what all goes into a floating slab.

 

[Avadon]

WEll I am certainly up for the challenge. I have some friends that are in the concrete business so getting ahold of one of them for the day would not be too much of a challenge. I just wanted to know what all goes into a floating slab.

Well I would definitely get some books on it.. and why your at it get "Build and repair concrete" Don Knotts is on the cover. I love this book. Goes into all the basics.. yah who would have thought Don Knotts was a concrete pro

 

[jomama45]

I have a question about pouring a concrete pad? I basically want to pour about an 8'x8' pad for a hot tub which will ultimately be under a deck.

In these situations, we've always poured the slab about 6-8" thick and on top of 3 or 4 sonotubes to stabilize the slab when surrounded by the deck.

Is there anything extra that needs to be done to house a hot tub, any extra bracing.

A grid of 1/2" rebar on 12"-18" centers would be plenty.

What is the procedure on prepping the surface to be poured onto. I can make the frame and such but how much earth do I need to remove before I put down the compacted surface and what surface do I put down to compact? Sand/Pea rock? I really don't know exactly how to do it but I hope with your help I can get it done.

Dig through all topsoil and at least dig down to solid soil. The slab should have at least 4" of 3/4" gravel or the like under it. I wouldn't recommend peas stone or sand, just a gravel that's a mixture of stone & fines.

 

[Vincer]

Before I knew anything about concrete (I still know pretty much nothing, other than you should dig down, etc, etc) I put a storage shed (premade sheet metal) up for my Dad in his backyard. I just put patio stones/pavers on top of sand. The sand was just there for leveling. This was in the Toronto area where the ground freezes every winter. Well I got lucky because a sheet metal shed puts almost no stress on the patio stones, and really the stones just keep it from blowing away. This was back in the early 90's. The only thing you could do online was dialup to a BBS or play Quake. I'm so glad forums like this are around with experts on them. I don't do anything "hard" without first checking forums and maybe reading some books!

Sorry, this post is completely off topic!

V

 

[Knucklez]

when it comes to hottubs (and pools) they are supposed to be bonded & grounded. i mean, an earthing ground grid, not just the electrical supply. i'm not exactly sure how to do this, but i envision the rebar grid to be sufficient as long as it ties to a ground rod. at least in canada, rule 68-058 applies to hot tubs and requires that the reinforcing steel (concrete rebar) b e bonded with a minimum of four connections equally spaced around the perimeter. i have a feeling that nobody actually does this, so maybe my interpretation is wrong?

bulletin 68-7-6 is a useful FAQ too for wiring.

i don't really see the need for sonotubes under a hottub. with drain gravel & reinforced concrete slab it should be fairly stable. i know lots of people that have just a poured slab and it seems fine... but that's just an ad-hoc observation

Knucklez

 

[Vincer]

Given that that grounding stuff is required, and is probably there because ... human bodies soaking in water with electrical equipment is involved...might be good to get a pro this time.