Slabs poured on ground that was prepared first

What sits under a slab decides everything

A slab is only as good as what it sits on, and around here that means sand. Tampa dirt is mostly sand with pockets of organic muck where something used to grow, and those pockets are the trouble. Sand compacts fine when it is confined and moist. Muck keeps settling for years after you have covered it. So the first thing on any pad is stripping the topsoil and roots out and getting down to material that will actually hold, then compacting it in lifts instead of dumping the whole depth at once and rolling the top of it.

After the base is right, the form work has to be right. We set the forms to the elevation the pad needs, check the diagonals so the corners are actually square, and pin the boards so nothing bellies out when the concrete pushes against them. A form that moves an inch under load gives you a pad with a wavy edge and a thin corner, and you cannot fix either one after the fact. You live with it or you break it out.

Then the steel. Rebar or mesh gets tied and set up on chairs so it sits in the middle of the pour, not laying on the ground where it does nothing but rust. Vapor barrier goes down on anything that is getting enclosed, lapped and taped at the seams, because a slab with no barrier under it will push ground moisture up through the surface forever and take your flooring adhesive with it.

• Topsoil and roots stripped, base compacted in lifts
• Forms pinned, squared on the diagonal
• Steel tied and chaired off the ground
• Vapor barrier lapped under enclosed slabs
• Thickened edges and footings poured monolithic

Footings for additions on Florida block

Most of the older houses in this part of Hillsborough County are concrete block on a slab, single story, with a stucco skin over the block. When you add a room to one, the new footing has to carry block just like the original does, which means a trench dug to bearing, steel run continuous through it, and dowels left standing where the new wall will go. Skip the dowels and the addition is sitting next to the house instead of tied into it.

The joint between old and new is where these go wrong. Two slabs poured years apart will never move exactly together, so we drill and epoxy dowels into the existing slab edge so the new pour is pinned to it, and we keep the top of the new slab at the same elevation as the floor inside. An addition floor sitting a half inch proud of the house floor is a threshold problem in every doorway and a trip you feel every time you walk it.

We also look at where the water goes before anything gets poured. An addition eats yard, and yard is where the roof runoff used to land. If the new footing blocks the path water took to leave the property, you have moved a drainage problem to the back door of a room that did not exist last month, and block walls sitting in standing water will tell you about it through the paint.

Sheds, carports and barn pads

A shed pad and a barn pad are not the same animal. A shed wants a flat, level slab with a thickened edge so the walls have something to sit on and the perimeter does not crumble when the mower clips it. A barn pad takes weight, gets hosed out, and has animals or equipment on it, so it wants a heavier section, more steel, and a surface with enough texture that it is not a skating rink when it is wet. We ask what is going on the pad before we decide the section, because the answer changes the pour.

The other thing a pad needs is a plan for water at the edges. On the barn pads and carports we build, that usually means a step down at the opening, so rain running across the apron drops away from the slab instead of running back under the wall line. Nicola Paille put it this way: "Did a great job on my concrete pad for my barn! Even ensured step downs so water doesn't seep in! Very professional and competent workers! AND reasonably priced! So thankful for Jose and the team!"

Carports catch the same problem in a different shape. A carport slab that is dead flat holds a puddle in the low spot forever, and a vehicle parked in that puddle keeps the slab wet on the underside of the tires all week. We pitch these away from the house, usually a light fall you would not notice walking on it, and finish them with a broom texture that gives grip without being rough enough to scrape a knee.

Heat, rain and how a slab cures

Florida heat works against a fresh slab in a way people do not expect. Concrete needs water to gain strength, and a slab poured on a hot, breezy afternoon loses surface water faster than it can bleed more up, so the top skins over while the body underneath is still soft. Finish it in that condition and you seal water into the slab, which comes back later as a dusty surface that sweeps off in powder. Early starts help, which is part of why the trucks roll early on our jobs.

Rain is the other half of it. An afternoon storm on a slab that has not set will wash the cream off the top and leave the aggregate showing, and there is no fixing that with a trowel. So we watch the sky before we call for concrete, and we would rather move a pour than start one we cannot finish clean. A pad that is one day late is a pad. A pad that got rained on in the first hour is a demolition job.

Then there is the cracking. Concrete shrinks as it cures, all of it does, and the only choice is whether the cracks go where you put them or where they feel like going. Control joints get cut or tooled at spacing that suits the slab thickness and the shape of the pad, and inside corners get relief because that is exactly where a crack will start. A hairline in a joint is the slab doing what it was told. A crack running across the middle means nobody told it anything.

How we quote a pad and what happens next

An estimate on a slab starts with standing on the ground it is going on. We look at what is there now, whether the spot holds water after a storm, how far a truck can get to it, and whether anything has to come out first. Access matters more than people think on Hillsborough lots, because a backyard pad behind a narrow side gate is a wheelbarrow job or a pump job, and both of those are a different day than a truck backing up to the forms.

Then we walk you through what the pad actually needs and why, in plain words, before there is a number attached to it. Jessica Gonzalez wrote it better than we would: "Jose was very easy to talk when giving me my estimate. He explained exactly what needed to be done and did a great job breaking down the price. His crew arrived on time got the job done and made sure to leave everything cleaned up. I appreciated this companies professionalism and work ethic. I will be using them for any other concrete projects and 100% recommend there services. Thanks again top quality work!"

If a permit or an inspection is part of your job, we build for that from the start rather than hoping it passes. B Vargas had one after the fact: "José and his company did an impeccable job. I recommend them without hesitation. I even had an inspection a few weeks after the work was completed, and the inspector confirmed that the work was done with excellent quality concrete and proper drainage." Estimates are free, we can start one online, and the phone is (813) 812-1892.