A shed is only as good as what it sits on. Set one on blocks in wet coastal sand and it tilts, the doors stop closing and the floor rots. A concrete slab fixes all of that. It stays level, keeps the floor dry and holds heavy tools and stored gear for years.
Coastal Concrete Wilmington pours shed and workshop slabs in Wilmington NC for backyard sheds, hobby shops, detached garages and small storage buildings. We are locally owned, and we give a free written estimate before work starts.
Choosing the right shed slab
A small garden shed may only need a four inch slab with a gravel base. A workshop with a lift, a welder or a heavy workbench needs more, often five or six inches with steel. We ask what you will store and use inside, then size the slab to match.
Plan the footprint with some room to spare. A slab a few inches wider than the building keeps water from running under the walls.
- Four to six inch thick slabs
- Gravel base and a vapor barrier
- Anchor bolts or sleeves for the building
- A thickened edge for heavier buildings
Keeping a shop dry on a wet lot
Wilmington lots can hold water, and sheds placed in low spots get wet floors. We raise the pad a few inches above the ground around it, slope the surface slightly and keep gutters and downspouts in mind. A plastic vapor barrier under the slab stops moisture from rising through the concrete.
Tools rust and wood swells when a shop stays damp, so a dry slab pays for itself.
Working with your building kit or builder
Many sheds come as kits with a plan for the floor. Send us the plan, and we will match the slab size, the anchor points and the door sill height. If a builder is putting up a metal or wood frame, we coordinate the pour date so the slab is ready when they arrive.
See concrete slab installation, concrete pads and concrete carport slabs.
Shed slab cost, timing and next steps
Price depends on size, thickness, base work, steel and access. Most shed slabs take a day to pour, plus a week of cure time before the building goes on. We give you a written price and a clear schedule.
Call us any day from 5 AM to 10 PM or use the contact page. Tell us the size of the building and what you will use it for.
Shed and Workshop Slabs questions answered
How thick should a shed slab be?
For a light storage shed, four inches is usually enough, poured over a few inches of compacted gravel. For a workshop, a shed that holds a riding mower and heavy tools, or a building that sees truck traffic, five or six inches with steel is a better choice. Heavier buildings often need thicker edges as well.
The base is as important as the thickness. In sandy coastal ground, we remove roots and loose soil, then compact the gravel in layers. We also add a vapor barrier to keep out moisture. Tell us what you plan to keep inside, and we will recommend a thickness and give you the price in writing.
Send the plan or the kit sheet with your call, and a concrete company in Wilmington NC can match the shed slab to your building. Ask us to verify the door height, since a thin curb or a ramp changes how the shed slab meets the floor.
Do I need a permit for a shed slab in Wilmington?
It depends on the size and use of the building. Small sheds under a certain size often need no permit, but they still must follow setback rules. Larger sheds, workshops with power and detached garages usually need permits for the building and sometimes for the slab. Flood zones and HOA rules can add limits.
We help you check before we pour. Tell us the address and the building size, and we explain what usually applies. We also call NC811 before digging. If a permit is needed, we make sure the slab is ready for inspection. A little planning at the start prevents stop work orders and costly changes.
Tell us what you will keep inside and how heavy it is, and we will pick a thickness that fits your shed slab. Tell us about the heaviest tool or machine you will use, and we will thicken the slab under it and add steel where the load will sit.
Can you pour a slab for a metal workshop building?
Yes. Metal buildings usually come with a plan that shows the slab size, the thickness and the anchor bolt layout. We follow that plan exactly, because the building frame must line up with the bolts. We set the bolts or sleeves while the concrete is wet, and we check their positions twice.
We also talk with your building crew about the schedule, so the slab has enough cure time before the frame goes up. See concrete slab installation. If you do not have a plan yet, we can explain what a building of your size usually needs and tell you when an engineer is wise.
Anchor bolt positions are the most common mistake, so we check them twice on every shed slab we pour. Ask us to leave a small apron at the door, which makes it easy to roll a mower, a cart or a bike in and out of the building.
How do you keep a shed slab from flooding in a storm?
We raise the pad a few inches above the nearby ground, so water runs around the slab and not onto it. We slope the surface away from the door and plan where the water goes after it leaves. In a low spot, we may add gravel, a swale or a drain.
We also look at the roof. A shed without gutters sends rain straight to the base of the walls, so we suggest gutters or a gravel strip. During the estimate, we walk the lot after a rain when we can, since that shows us where water collects. A slab that is dry in every storm is the goal.
A short walk after a rain shows us where water collects, and that helps us raise the shed slab in the right spot. Tell us how close the shed will sit to trees and fences, and we will plan the slab so roots and walls do not cause trouble in a few years.
Can I have a slab poured and build the shed myself?
Yes, and many customers do. We pour a flat, square slab with anchor bolts or sleeves placed to match your plan. You then build on a strong base, and you do the part you enjoy. We can also add a small apron or ramp at the door if you want one.
Share the plan or the kit instructions with us before the pour. A wrong bolt position or a slab that is a few inches off size is hard to fix later. Wait for the concrete to cure before you start building, usually about a week for light work. We tell you the exact day and the steps to take.
If you plan to build the shed yourself, we leave a clean, square slab and share the best day to start building. Ask us about a floor drain or a gentle slope if you plan to wash tools or equipment, since a dry floor keeps tools from rusting in humid air.
What about a shed slab on a slope or near trees?
A slope needs a level pad, which means cutting into the high side or building up the low side with compacted fill. We plan the grading so the slab sits on firm ground, not loose dirt. Trees need care too. Roots near a slab can lift it, and cutting big roots can harm the tree.
We move the slab away from large trunks when we can. When we cannot, we use thicker concrete, steel and joints that give roots room. We show you the plan and the price for each option at the estimate. Our goal is a slab that stays flat and a yard that stays healthy.
Tree roots near a shed slab need a plan, and we talk through the choices with you at the visit. Tell us when you want to start building, and we will set a cure schedule that gets your frame on the slab at the right time.
Ready for a free estimate? Call (910) 981-2124 any day from 5 AM to 10 PM, or use the estimate form. Coastal Concrete Wilmington is locally owned and gives clear written estimates for patios, driveways and slabs.