How to Build a Concrete Pad for an AC Compressor

A concrete pad for an AC compressor will provide a stable, secure base for this important piece of equipment. You'll ensure that the compressor sits at a level pitch, and is protected from excessive moisture and mold that may occur if you have the compressor sitting on the ground or on an unstable platform. Properly built, your concrete AC compressor pad will last for many years.

Difficulty: Moderate

Instructions

Things You'll Need:

• Shovel
• Gravel
• 1-by-6 inch lumber
• Concrete
• Level

1. Decide where you'll be placing your concrete pad. The pad should rest on a area of stable earth, and should be in a location that fits the needs of the compressor--that is, close enough for any connections that the compressor must make to your cooling system. Once you've decided where it will be, mark the corners of a 4-by-4 foot square. This is where you'll place your pad.

2. 
    

   Dig out the square you've marked to a depth of 18 to 24 inches. Fill the bottom of the square with medium-grade (#2 or #3) gravel until the gravel is about 6 inches from the ground level. Use the carpenter's level to make sure the top of the gravel is roughly level.

3. 
    

   Line the inside of the pit with a frame made from the 1-by-6 inch lumber. The frame will hold the concrete when you pour it. Ensure that the frame is square and sitting level for the best results.

4. 
    

   Mix the concrete with water. Quckrete is perfect for do-it-yourselfers, and is readily available at home building supply and hardware stores.

5. Pour the concrete, smoothing as you go by dragging a 2-by-4 inch board over the concrete. Check with your carpenter's level to see that the surface is level when you've reached the desired height. After 24 hours, remove the 1-by-6 inch forms, then allow the concrete to set for at least 1 week before placing an heavy objects upon it.