construction of concrete base for A/C compressor


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Old 04-08-16, 09:44 AM
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construction of concrete base for A/C compressor

If we construct a concrete base for a new A/C system, I foresee a platform of about 3' x 3' in size. The soil at the base location would be removed to a depth sufficient to allow some gravel to be spread as a base for the concrete which would be several inches thick.

I'm wondering whether rebar should be included in this project?
 
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Old 04-08-16, 10:00 AM
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They make premade pads for A/Cs.
 
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Old 04-08-16, 11:38 AM
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The house I'm referring to belongs to my son. I'm aware of the premade pads. I have one of them under my A/C, which is over 20 years old. The pad has settled over the years. We were thinking of concrete as a better, more stable base.
 
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Old 04-08-16, 12:15 PM
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Remove grass and loose soil, put down 4-6" of crushed rock, well compacted, and high enough so water drains away and you'll have a stable base. Once you've done that, you might as well put a precast down because it's inadequate base preparation that makes them settle, not the pad itself.

If you really want to pour a slab, you won't need rebar if the base is good.
 
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Old 04-08-16, 12:48 PM
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When I poured the pad for my heat pump I removed the top soil and formed it up [over slate rock] Poured ready mix bags with no rebar. That was 18 yrs ago, it's still level and in great shape.
 
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Old 04-08-16, 06:01 PM
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The ready made pads are mostly styrofoam with a concrete coating. They are not subject to the freeze/thaw issues that can happen with concrete. Just something to consider in a northern climate.
 
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Old 04-08-16, 06:30 PM
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Whole lot cheaper and faster to use a preformed pad.
 
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Old 04-08-16, 10:59 PM
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What's the opinion of the plastic pads? I've used them over a rock gravel base with no issues.
 
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Old 04-09-16, 12:29 AM
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My A/C has been sitting on a plastic pad for about 10 years, no issues.
 
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Old 04-09-16, 04:57 AM
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Dig down below your areas frost line by at least a few inches and gravel so it does not shift during freeze/thaw cycles. Pour a min 3in deep pad with quikrete concrete mix for a condenser. No reinforcement is required if the gravel base is good.
 
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Old 04-19-16, 12:46 PM
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Whole lot cheaper and faster to use a preformed pad.
Does this mean a concrete product, or is it made of some other material? Where are they sold?
 
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Old 04-19-16, 04:15 PM
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Here is a 72 lb. one you can have shipped! Equipment Slabs | CONCRETE REINFORCED EQUIPMENT PAD | 2424CONCPOOLPAD 24"X24"

Precast are generally solid concrete but they do make hybrid ones.

Plastic ones you can order at the big box stores.
 
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Old 04-19-16, 05:34 PM
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Wow, the shipping would make me get 3 or 4 bags of premix and short rods of rebar and form up my own which I did, but for a 100 gal. propane tank that I no longer have. For my a/c I have and used 2 concrete curbs from a nearby plant.
 
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Old 04-19-16, 06:58 PM
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The preformed ones around here are 90% styrofoam with a concrete shell. Light enough to lift with one hand. Continue your search.
 
 

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