House Pads in Hammond, LA

How we build a house pad

Every pad starts on the footprint, the ground the building will cover. Grass, roots and topsoil come off first, since organic material breaks down and lets the dirt above it sink. Soft, wet ground gets dug out until the machine reaches dirt that holds. A wooded lot needs land clearing before any of this, and an old slab in the way needs concrete removal.

Then the pad goes up in lifts of fill dirt, which we sell and haul in ourselves. A lift is one thin layer. Our machines pack each layer hard before another goes down. That is how a pad holds up a slab or piers instead of sinking under them.

Your builder gives us the slab size, and the pad runs out past it on every side. The top gets a slight crown, high in the middle, so rain sheds to the edges. The sides slope down into the yard so water keeps moving away from the pad. Shaping the rest of the yard to drain is land grading, which we handle too.

Rain sets the pace on pad work here. Hammond averages 64.2 inches of rain a year, spread over about 116 days. Soaked fill will not pack tight, so we wait for the ground to dry out. A rainy stretch can push the finish date back.

Who sets the height of a house pad

Pad height is never our number to pick. It comes from your plans, your surveyor or the parish. In a mapped flood zone, parish or town rules set a minimum floor height above the base flood elevation. A surveyor finds where that height falls on your lot, and the pad goes up to meet it.

LSU AgCenter gives the base flood a 1 in a hundred chance of being matched or topped in any year. The base flood elevation is how high that flood's water would rise. On the flood map, the high-risk zones start with the letter A or V. In those zones, the federal minimum puts a new home's lowest floor at or above the base flood elevation.

In A zones, LSU AgCenter says a building may meet its elevation requirement by sitting on compacted fill. That is where a house pad comes in on a low lot. Some Louisiana communities also require freeboard, extra height above the base flood elevation. Common values run 12 or 18 inches, but your parish or town sets the number for your lot.

If two flood zones touch the building, the parish goes by the more hazardous one. Its current flood maps took effect July 22, 2010. The parish holds an elevation certificate for all new development, which puts the floor height on record.

Mobile home dirt pads and the federal standard

For mobile home dirt pads, the federal rule book is HUD's installation standard for manufactured homes. Under it, the foundation has to sit on firm, undisturbed soil or on compacted fill. That fill must be compacted to at least 90 percent of its maximum relative density. The rule says this helps prevent settling or sagging.

All organic material, such as grass, roots, twigs and wood scraps, comes out where the footings go. Then the site gets graded to move surface water away and prevent water build-up under the home. The ground must slope at least one-half inch per foot away from the foundation for the first ten feet. Where a lot will not allow that slope, we cut swales to carry the water away instead.

HUD also says the soil type and bearing capacity must be determined before the foundation is built and anchored. Ground that looks like peat, organic clay or uncompacted fill calls for a registered geologist, engineer or architect. That person makes the call on the soil, and we build to it.