Backyard Shed Build Part 1 - My First Concrete Pour!
Stop Wasting Wood
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My garage is full. I need an overflow space for gardening tools, lawn mowers, and potentially wood storage. I decided to build an 8x10 Garden Shed.
But a shed is only as good as its foundation. If you put it on dirt, it rots. If you place it on pavers, it settles unevenly. I chose the nuclear option: A solid reinforced concrete slab.
The Plan
- Size: 8ft x 10ft.
- Thickness: 4 inches.
- Perimeter: 12 inches deep (thickened edge) for structural support.
Material & Tools
- Concrete: 50 bags of 80lb Quikrete. (Yes, that is 4,000 lbs of rock).
- Rebar: 1/2" steel bars.
- Lumber: 2x6s for the formwork.
- Mixer: I rented a tow-behind electric mixer. Do not attempt this in a wheelbarrow unless you are The Hulk.
The Build Process
Step 1: Excavation
I marked the corners with stakes and strings. I used the 3-4-5 triangle method to ensure the corners were square.
- Digging: I stripped the sod/grass. Then I dug the perimeter trench 12 inches deep. This "footing" prevents the slab from cracking under the weight of the walls.
Step 2: Formwork
I built a box out of 2x6 lumber.
- Leveling: This is the most critical step. I used a laser level to ensure the top of the form was perfectly level. If the form is crooked, the floor is crooked.
- Stakes: I pounded wooden stakes into the ground every 2 feet to support the forms. Concrete pushes OUT hard. If your form bursts, you have a disaster.
Step 3: Reinforcement
Concrete has great compression strength (you can crush it), but terrible tensile strength (you can snap it). Steel solves this.
- Rebar Grid: I laid out a grid of rebar on "chairs" (plastic stand-offs) to keep the steel in the middle of the slab.
Step 4: The Pour (Controlled Chaos)
I invited 3 friends. I bribed them with pizza and beer (for after the pour).
- Mixing: One person on the mixer. Water, Bag, Mix, Dump.
- Hauling: One person wheelbarrowing to the form.
- Spreading: One person with a shovel/rake moving the grey slush into the corners.
- Screeding: Two people use a long straight 2x4 to saw back and forth across the top of the forms, leveling the wet concrete.
Step 5: Finishing
Once the water sheen disappeared, I used a magnesium float to smooth the surface. I didn't want a shiny "garage floor" finish (too slippery), so I hit it with a broom to create a non-slip texture.
Conclusion
My back was broken. My friends hated me. But the next morning, I stripped the forms and there it was: A permanent, rock-solid monolith. Phase 1 complete. Now we frame!