Larkspur Garage Floor Contractors

Open the door, walk to the end of the drive, and turn around. No flashlight or moisture meter needed for the first pass. A failing garage slab announces itself in the ten feet nearest the opening, and that strip is visible from outside on any sunny morning. Dark band that never dries. White chalk blooming out of the surface. A lip where the floor meets the apron. Crumbling along the front edge that worsens each spring.

We get called for all of it around Larkspur, and the detached shops on these properties fail differently than attached three-car bays. An unheated shop behind the house in Perry Park sits at ground temperature all winter, a different life than a garage sharing a warm wall with the kitchen. Same concrete, different problems.

What the door line is telling you

The first ten feet of a garage floor take everything. Snow melts off the vehicle and runs down there, road chemistry riding in on the tires with it. That edge sits closest to outside air, so it freezes and thaws while the back of the garage stays steady. And it's the strip water has to cross to leave. Poured flat, or tipped inward, and the water never leaves at all.

Flaking and pitting along there is surface damage from salt and freezing, often ground off and rebuilt without touching the rest of the slab. A dark band that stays wet for days after everything else dried is a different story: moisture coming up from below through a slab with no vapor barrier, and no coating sticks over that. A lip between the floor and the apron is the third symptom. One of those two slabs is moving, and which one changes the fix entirely.

Door-up diagnosis

The plastic sheet that decides your floor's future

Under every garage slab we pour there's a ten mil vapor barrier, lapped wide and taped at the seams, sitting on clean compacted base. It costs a rounding error and it decides whether you can ever coat that floor. Builders skipped it constantly on older work, and plenty of shops out here went in as owner projects where nobody thought about it. Once the slab is down, that omission is permanent.

Two more details we don't negotiate. The floor falls toward the door, about an eighth of an inch every foot, so a truck dripping slush in February drains itself instead of building a rink. And joints go in a deliberate grid, cut the same day, breaking the bay into panels close to square. A garage is a big rectangle boxed in by walls that don't move, so it wants somewhere to shrink. Give it that place or it picks its own, usually where the door opening pinches the slab.

For unheated shops, cold is a design input. Footings and thickened edges go below frost depth, deeper here than what satisfies a building in the flats. A slab lifted by frozen ground each January cracks no matter how good the concrete is.

Coatings, and the one pour that likes cold weather

Order of operations trips people up. New concrete has to release its moisture before anything goes over it, so a coating waits at least a month, longer in an unheated building. Coat too early and the film lifts in sheets a year later, which looks like a bad product and is almost always a bad schedule. Want a coated floor? Say so before we pour, and the surface gets finished for adhesion instead of burnished slick.

Timing the pour is easier than most concrete work. A garage has a roof and walls, so no rain lands on a fresh finish, no sun cooks the surface, and the space can be heated and blanketed. That makes winter a workable season for garage floors, and a stretch when we can usually get to you fast. Frozen ground is the one condition we won't bend on, because a slab placed on frost settles the moment the ground relaxes.

You can call it before the breaker even hits the slab. Concrete black on the underside, damp base on a dry day, and there was never plastic down there. Those floors sweat every spring, and the owner has been blaming the epoxy for a decade.From the crew lead on these jobs