How to Pour a Concrete pad for a Boiler
A boiler pad is a necessity to support the intense an focused extra weight of a boiler. A concrete boiler pad allows the weight of the boiler to be spread over the slab, allowing the slab to carry the weight without cracking and the slab to retain a more economical design. You can pour a slab for a boiler easily, taking only a few extra steps beyond what's required to set up to pour a normal concrete slab. Does this Spark an idea?
Things You'll Need
- Orange spray paint
- 2-by-6 foam board
- Level
- Hammer drill (if needed)
- Rebar stakes
- Concrete mesh (4 inches by 4 inches)
- 2-by-2 concrete brick
- Concrete
- Concrete float
Instructions
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1
Mark out where in your room the boiler will go. It does not matter if the slab is poured or not yet; simply locate the rough center of the actual boiler itself and spray a dot with orange paint.
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2
Measure and mark a square in paint from the center point of the boiler. Check the specs of the boiler you have ordered. The width of the boiler is not important; what matters is the lbs of water or oil it will contain. For every 1,000 lbs, your square needs to extend a minimum of 2 feet past the external wall of the boiler you are going to install.
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3
Set your 2-by-6 form boards so they are lined up on the outside of the measurement you have outlined. If you are setting this form on an existing slab, use a hammer drill to drill holes and set rebar stakes inside the pad to attach the form boards to. If you are setting this pad in a slab that has yet to be poured, you have two choices. One option is to set the boards flush with the bottom of the slab to create two separate pours. To create a monolithic pour--pouring the slab and raised pad together--use longer rebar stakes and hang your 2-by-6 boards so the bottom of the pad form board is level with the top of the slab. Mark the top of your pad on the board.
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4
Cut a piece of wire mesh to fit inside the forms of your concrete pad for the boiler so there is a 2-inch clearance between the mesh and the inside edges of the form. Set the mesh in, raising it up on some 2-inch-by-2-inch concrete brick so it will be set in the middle of your pour height.
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5
Pour your concrete. Whether you are pouring the pad on an existing slab or as a monolithic pour, go very slowly when you begin. Pour a little concrete in the center of the mesh, then drop some concrete in each corner of your pad form and wait about 5 minutes to let that set up a bit to hold the shape of the pad. Then fill the pad and use a wood board to roughly level it off. Check the square of the form and make any adjustments needed before the concrete sets. Finish the pad with a float.
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Tips & Warnings
Setting up for a monolithic pour is tedious and time-consuming; however, it is the most economical way to pour both a slab and pad as you do not need to bring the concrete truck back a second time. With a little patience and time, you could save yourself hundreds of dollars.
A concrete pad for a boiler acts like a raft to support the weight of the full boiler on the slab. Do not skip adding an additional pad for a boiler as the weight can collapse into the slab and destroy the feed and drain angles of all attached pipes, causing damage that is extremely expensive to fix.
