36x18" concrete slab

[PoorOwner]

I want to pour a slab for a mini split outdoor unit. 36"x18" smallest you have seen.

do I need rebar for this size?

I have also seen some chicken wire in the middle?

is this ok to use this gravel for the base?

https://www.homedepot.com/p/SAKRETE-50-lb-All-Purpose-Gravel-100033870/100598894

 

[Stuart in MN]

I'd use one of the prefab pads instead. Put down some gravel for a base, drop one of these down on top, and you're done. https://www.homedepot.com/p/Diversi...PIPHorizontal2_rr-_-302850575-_-205317876-_-N I"ve had a similar pad under the condensing unit for my central a/c for more than fifteen years now with no issues.

 

[PoorOwner]

I have that plastic pad, I am trying to replace it. I don't know, I just couldn't get it to sit nice on the soil, plus the condenser is still tippy on it.

 

[benjamintmiller]

No, you do not need rebar or mesh for a pad as small as that.

And yes, that type of gravel is perfect under concrete. You don't need the gravel either if you don't want it.

 

[bad_idea]

Minimal load for a foot print that size. Scrape the vegetation off the soil, nail some 2x4s together as a form, and pour some quikrete in there.

 

[MushCreek]

Mini-splits are very light, so you don't need much. I mounted mine to the wall, about three feet off the ground to keep them out of the leaves and snow. It turned out to be a good idea, as the service ports are down near the bottom. You'd have to lay on the ground to work on them.

 

[ConCretin]

What has become of the GJ?!? Of course you need rebar and lots of it. I'd say at least #8's at 6" centers........... Just kidding. The previous posters have it about right.

 

[kbs2244]

I think most of the pre-cast concrete ones hove some kind of steel in them.

 

[chaosracing]

I think most of the pre-cast concrete ones hove some kind of steel in them.

Not really. Depends on the mix used. Some just use wire fabric, others use fiber mesh, other use nothing, but I have not seen any pads with rebar in them.

As mentioned above though, if you can, I would mount to the building and raise it off the ground. Much better all around.

 

[rburke65]

Any idea what a precast slab that size, might cost?

 

[ItsNemo]

Honestly a couple 2x2' patio stones on some gravel would be plenty for a mini-split.

 

[Stuart in MN]

Any idea what a precast slab that size, might cost?

From the link I posted earlier, $29.00.

 

[renloy]

What has become of the GJ?!? Of course you need rebar and lots of it. I'd say at least #8's at 6" centers........... Just kidding. The previous posters have it about right.

Don't forget the vapor barrier and insulation too. Don't want that minisplit to get cold!

 

[Radix2]

Footers down to bedrock, 6000psi mix minimum.

 

[NUTTSGT]

I like overkill personally. I'd probably use some rebar to hold the slab together if it cracks.

You mention the current pad is tippy, I think it will do the same thing if it cracks/breaks.


Personally, I'd scrape the topsoil off, add stone (local quarry close) form with 2x4s and add a few pieces of rebar. A 10' stick of 1/2" (#4) will give you two 30" pieces and four 12-15" pieces to tie together. It'll cost you about $5 or buy a 20' and keep the extra around for future use. . . .like tent/E-Z up stakes.

Overkill, yeah but it's not a sidewalk, you're actually placing a piece of equipment on it.


BTW, a pad 3.5" thick, 18"x36" will call for three 80lb bags of Quikrete.

 

[PWC Repair]

What has become of the GJ?!? Of course you need rebar and lots of it. I'd say at least #8's at 6" centers........... Just kidding. The previous posters have it about right.

But what about the footer? I'd say 4" thick and 12" deep should do. Might even french drain the uphill side with perforated 1" pvc and pea gravel.

And don't forget the vapor barrier before you pour!

 

[rburke65]

Well for $29 not worth the hassle.

 

[timewarp]

I have that plastic pad, I am trying to replace it. I don't know, I just couldn't get it to sit nice on the soil, plus the condenser is still tippy on it.

If you already have the pad and realy want to mess around with concrete, get a bag of quickcrete mix it and place it on the ground spread out the size of the pad, then push the pad down on it, just use the quickcrete like grout to make the ground level under the pad.

 

[PoorOwner]

If you already have the pad and realy want to mess around with concrete, get a bag of quickcrete mix it and place it on the ground spread out the size of the pad, then push the pad down on it, just use the quickcrete like grout to make the ground level under the pad.

probably will try this first. And fill some of the squares under the plastic with concrete too, with 80 lb added it should help