How to Pour Footings for a Deck
Pouring concrete footings is a key step in building your dream deck. Before you begin, however, there are a key things to keep in mind.
First of all, whether you're pouring a lot of footings or just a few, it's better to have someone help you. Even power mixing is strenuous, and pushing concrete around with a mixer or wheelbarrow can quickly tire you. If your deck is small, with footings at only its four corners, preparing premixed bags of concrete in a wheelbarrow is quick and cost-effective. Pouring more than four to six footings is best done with a power mixer or ready-mix from a concrete truck.
Also try to rent a small mixer with wheels, if available. Move the mixer to each hole, prepare the concrete, and pour. Don't try moving the mixer with concrete in it. If a portable mixer is not available, rent a stationary model and move the concrete to the holes in a wheelbarrow. Laying a ramp of 2x12s will make this task easier and will minimize damage to your lawn.
No matter how you prepare the concrete, measure the dry ingredients first (in shovelfuls), mix them in the power mixer or wheelbarrow, then add the water.
You'll need about an hour per footing to mix and pour concrete, and install the J-bolt. Prep for the job by digging holes and installing tube forms.
What You Need
- Power mixer
- Round-nose shovel
- Mason's hoe
- Speed square
- Concrete (premixed bags or loose materials)
- 2x4 screed
Step 1: Mix Concrete
Bring a mixer or wheelbarrow to the hole and mix the concrete. If working alone, shovel the concrete into the hole. With a helper, position the mixer or the wheelbarrow so the concrete will pour from it when tipped. Guide the concrete with a shovel.
Step 2: Consolidate Concrete
When the footing is half full (and again when full) consolidate the concrete in the tube by working a 2x up and down in the mix. This will remove air from the mix and bring water to the top, aiding in the proper curing of the mix.
Step 3: Remove Excess
Overpour the concrete into the tube and screed off the excess with a short length of 2x4. Seesaw the 2x4 as you pull it across the top of the tube to level the mix. Simply pulling the 2x4 straight across will drag mix out of the form.
Step 4: Insert J-Bolt
Let the concrete set up just until it begins to firm, and insert a J-bolt into the center of the form. Set the bolt as precisely as possible, checking with a tape measure on opposite sides of the form. If the bolt ends up slightly off center, you can correct this with an adjustable post anchor.
Step 5: Adjust Bolt and Concrete
Push or pull the J-bolt to leave 1 inch of thread above the surface of the concrete. Make sure the bolt is vertical by checking it with a speed square. Repack loose concrete with a pointed trowel, adding a little more if necessary. Let the concrete cure before installing post anchors.
Concrete Tips and Tricks
If using premix, empty complete bags into the mixer. Using partial bags can result in an improper mix. If using dry mix, measure the right proportions of cement, sand, and aggregate into the mixer in shovelfuls. Turn the mixer on to mix the dry materials thoroughly. Then add about one-half the prescribed water, and mix thoroughly. Continue mixing, adding water a little at a time, until the mix just clings to the side of a shovel turned on edge.
Mixing Concrete in a Wheelbarrow
If you're mixing concrete in a wheelbarrow, get a large one—a lot of concrete will spill from a small wheelbarrow as you mix it. Pour the contents off a complete premixed bag into the wheelbarrow (never a partial bag) or measure in the dry ingredients with a shovel. Mix the dry mix together with a hoe, then mound it into the center of the wheelbarrow and make a depression in it.
Add about one-half of the total water into the depression and work the dry mix into the water with a hoe. Then work the mix back and forth the entire length of the wheelbarrow with the hoe, scraping up dry material from the bottom. Add water as necessary, working it into the mix before adding more. When the concrete clings to a trowel turned on edge, it's ready.
Using Precast Piers
Precast concrete piers are engineered to accommodate joists for ground-level decks without footings or posts and anchors set in footings. If you bed a pier in a concrete footing, however, you need to soak it in water. A dry pier set in a wet footing will draw moisture out of the concrete, weakening it. Soak the pier in a tub of water for several minutes, then center it on the footing before the concrete sets up.