What a Concrete Slab Costs in New Hampshire

There is no single price for a concrete slab. The number comes from the work the slab actually needs, and most of that is decided before any concrete arrives. This page explains what moves the figure up or down so you can read a quote properly and compare two of them on the same terms.

Frank Bernard does not publish a price per square foot, and you should be careful with anyone who does. A rate quoted without seeing the site assumes a flat, accessible, well-drained pad and a simple finish. Those assumptions are what estimates get wrong. What follows is how we look at a slab when we price it.

What actually drives the cost

Thickness and what the slab carries

A slab that parks a car is not a slab that takes a loaded forklift or a storage unit full of stock. Thickness follows the load, and so does the concrete specification. Going from a residential floor to a slab rated for commercial traffic changes the volume of concrete, the reinforcement, and often the subgrade work underneath it. This is usually the single largest line in the difference between two slabs of the same square footage.

Reinforcement

Wire mesh, rebar on chairs, fibre in the mix, or a combination. The engineer or the building drawings set this, not preference. Reinforcement adds material and it adds labour, because steel has to be placed, tied, and held at the right height while concrete goes around it. A slab drawn with a rebar mat costs meaningfully more to place than the same slab with mesh.

Subgrade and site preparation

Fine grading is part of every job we do, and it is where a lot of quotes diverge. A pad that is already stable, compacted, and close to grade is cheap to finish. A pad that needs material brought in, soft spots dug out, or significant cut and fill is a different job. If the gravel is not right, the slab on top of it will not be right either, so this is not a place to save money.

Access for the trucks and the pump

Concrete has to reach the forms. A slab a mixer can discharge into directly is the cheapest case. A slab that needs a pump, a boom, or buggying across a site costs more, and tight or soft access can add time to every truck. Slopes, overhead wires, trees, and anything already built on the site all affect this. It is worth telling us about access early, because it changes the plan more than people expect.

Formwork and edges

A plain rectangle is quick. Thickened edges, steps, curves, a drop at a door line, or a slab that has to tie into something already built all take forming time. We fabricate custom angle iron ledger forms in our own machine shop, which is how we hold a consistent edge on storage buildings, and those edges are hand finished rather than skim coated. That is labour, and it shows in the number.

Finish

A broom finish, a hard trowel floor, and a surface being prepared for a later coating are three different amounts of work and three different crew sizes. Interior floors that have to be flat to a tolerance take longer and need more people on the slab at the right moment. We do not do stamped or pervious concrete, so that is not part of our pricing conversation.

Season and schedule

Cold weather work needs blankets, heat, or admixtures, and sometimes all three. Placing in the shoulder seasons in New Hampshire is routine but it is not free. A slab that has to go in on a fixed date, or in a sequence set by other trades, has less flexibility than one that can be scheduled around the weather.

Distance

We work within 100 miles of Rochester, New Hampshire, no further south than Danvers, Massachusetts. Beyond that radius we will still talk, but scope and an additional hospitality fee are agreed in advance rather than discovered later.

How slab size changes the arithmetic

Square footage is the obvious driver, but cost does not scale evenly with it. The fixed parts of a job, mobilising equipment and crew, setting up, and getting the first truck on site, are much the same whether the slab is small or large. That means small slabs carry a higher cost per square foot than big ones, and the difference is not small.

Some common sizes and what tends to matter most on each:

• 10x10 and 12x12. Shed pads, generator pads, small additions. Almost entirely driven by setup and access rather than by concrete volume. Combining several small pours on one visit is usually far cheaper than doing them separately.
• 20x20 and 20x30. Garage floors, small metal buildings, patios. Big enough to be efficient, small enough that access and finish choice still dominate the figure.
• 30x30 and 30x40. The common pole barn and workshop range. Thickness and reinforcement start to matter more than setup here, because the drawings usually specify a slab that carries real load.
• 40x60 and larger. Commercial floors, storage buildings, equipment buildings. Placement planning, joint layout, and crew size drive these. A slab this size is often placed in bays rather than in one go, and how it is divided affects both cost and the finished result.

Thickness interacts with all of these. A four-inch slab and a six-inch slab of the same footprint are not a small difference once you add the extra concrete across the whole area and the subgrade work that usually comes with the heavier spec.

What we need to give you a real number

A quote is only as good as the information behind it. To price a slab properly we want the dimensions and the specified thickness, the reinforcement called for on the drawings, the finish you need, the town, and an honest description of the access. Plans are ideal. If a plan is preliminary, tell us which parts are still being developed so the estimate reflects where the design actually is.

What you get back is a scope and a price, with any changes or additional distance fee discussed before work proceeds rather than appearing afterwards. We do not accept credit cards, and payment arrangements are part of the estimate conversation.

Comparing two quotes fairly

If two numbers are far apart, the scope is usually different, not the margin. Check whether both include fine grading, whether both are pricing the same thickness and the same reinforcement, whether the finish is the same, and whether site preparation and any needed gravel are in or out. A quote that is cheap because it assumes a pad is ready, when it is not, stops being cheap very quickly.

Concrete Slab Cost FAQs

Why will you not give a price per square foot?

A rate quoted without seeing the site assumes a flat, accessible, well-drained pad and a simple finish. Those assumptions are where estimates go wrong. Thickness, reinforcement, subgrade condition, access and finish all change the figure, so we price from the actual scope rather than from a published rate.

What is the biggest factor in the cost of a slab?

Usually thickness and the reinforcement that comes with it, because both follow the load the slab has to carry. Going from a residential floor to a slab rated for commercial traffic changes the concrete volume, the steel, and often the subgrade work underneath it.

Does a small slab cost less per square foot?

No, it normally costs more per square foot. Mobilising crew and equipment and getting the first truck on site costs much the same whether the slab is small or large, so those fixed costs are spread across less area. Combining several small pours into one visit is usually far cheaper than doing them separately.

What information do you need to quote a concrete slab?

Dimensions and specified thickness, the reinforcement called for on the drawings, the finish you need, the town, and an honest description of site access. Plans are ideal. If a plan is preliminary, say which details are still being developed so the estimate reflects the current design.

Why are two quotes for the same slab so far apart?

The scope is usually different rather than the margin. Check whether both include fine grading, the same thickness and reinforcement, the same finish, and whether site preparation and any needed gravel are in or out of each number.

Send your project details or call (603) 330-0776.