How thick should a concrete slab be for a garage or shed?

For most residential garages and sheds, a 4-inch slab is sufficient for standard vehicle storage. If you plan to store heavy equipment, RVs, or commercial vehicles, we recommend 5 to 6 inches with additional reinforcement. The slab thickness also depends on soil conditions and intended use, which we assess during the planning stage.

Do I need a vapor barrier under my concrete slab?

Yes, a vapor barrier is essential for any indoor slab or space that will be enclosed. It prevents moisture from seeping up through the concrete, which can cause mold, damage flooring, and create humidity problems. We install a polyethylene sheet under the slab before pouring to create an effective moisture barrier.

How long before I can use my new concrete slab?

You can walk on a new slab after 24 to 48 hours, but we recommend waiting at least 7 days before placing heavy equipment or vehicles on it. Concrete reaches about 70% strength in the first week and continues curing for 28 days. Rushing this process can cause cracks and structural problems, so patience is important for long-term durability.

Concrete Slabs & Flatwork

Strong, level concrete slabs for sheds, garages, workshops, and any project that needs a solid foundation.

Rebar reinforcement preparation for concrete slab in Brentwood, CA

What We Mean by Concrete Flatwork

Flatwork is any horizontal concrete surface. This includes slabs for sheds and garages, barn floors, RV pads, equipment pads, and commercial spaces. These projects require precise leveling and proper base preparation to support weight without settling or cracking.

Here in Brentwood, we pour slabs for all kinds of uses. Maybe you need a level spot for your storage shed, or you are building a workshop and need a solid floor. We have also done RV parking pads, pool equipment pads, and commercial loading areas. Whatever your project requires, we make sure the slab is built right from the ground up.

The key to a good slab is what you do before you pour concrete. Proper excavation, a compacted gravel base, and correct reinforcement prevent future problems. We see too many DIY slabs that look fine for a year, then start settling and cracking because the prep work was skipped. When you hire professionals, you get a slab that stays level for decades.

Common Slab Applications

Storage sheds and outbuildings
Detached garages and workshops
RV and boat parking pads
Equipment pads for HVAC units and generators
Barn floors and agricultural buildings
Commercial warehouse and loading areas

How We Design Your Slab

Not all slabs are the same. A shed floor does not need the same thickness or reinforcement as a commercial loading dock. We calculate the right specifications based on what your slab needs to support.

For residential projects, we typically pour 4-inch thick slabs with wire mesh reinforcement. If you plan to park vehicles or store heavy equipment, we go with 6 inches and rebar reinforcement. The base underneath also gets thicker for heavier loads. These details matter when you want your slab to last.

We also plan for drainage. A level slab sounds good in theory, but you actually want a slight slope to keep water from pooling. We create just enough grade to shed water without making your floor feel uneven. This prevents standing water that can lead to foundation problems over time.

Our Slab Installation Process

Every slab we pour follows a proven sequence that ensures strength and longevity:

Step 1: Site Assessment

We check your soil conditions, look for any drainage issues, and confirm the exact dimensions you need. We also verify that no utility lines run through your planned slab area.

Step 2: Excavation and Grading

We dig out the area to the proper depth and grade it for drainage. Any soft spots or problematic soil get removed and replaced with stable material.

Step 3: Base Installation

We add a layer of compacted gravel base. This provides drainage underneath and prevents the slab from settling. The base gets thoroughly compacted with proper equipment, not just tamped by hand.

Step 4: Forms and Reinforcement

We set level forms around the perimeter and add wire mesh or rebar reinforcement as needed. This steel reinforcement holds the concrete together even if minor cracking occurs.

Step 5: Concrete Pour and Finish

We pour quality concrete mix to the correct thickness and finish it smooth or with a broom texture for traction. The slab is properly cured to reach full strength.

Why Brentwood Property Owners Choose Us

We have poured hundreds of slabs since 2024, from small shed floors to large commercial projects. Our crew knows how to handle the clay soils common in our area and we factor in local weather conditions when scheduling pours.

We also understand that your project might be part of a larger build. If you are putting up a garage or workshop, we coordinate timing so your builder can start framing as soon as the concrete is ready. Need anchor bolts set for walls? We handle that during the pour.

Whether you need a simple shed slab or a reinforced pad for heavy equipment, we give you honest pricing and quality work. Ready to discuss your project? Call us for a free estimate and professional advice about what your slab needs to last.

Call (925) 536-0846