Foundation raising in Alexandria VA - a level house on a foundation built right

Raising a house in Washington, DC usually costs about $11,000 to $33,000 for a 1,000-square-foot home, and that's what the market charges in DC, not our price. Nationally, raising a house on piers or pilings above the flood level, or lifting it to replace the foundation, costs more than lifting the house alone, and putting in a basement costs the most. Your written estimate will show what's included for your house.

The whole process takes 4 to 8 weeks on average nationally, and the lift itself takes 2 to 7 days once the prep work is done. The schedule things I mentioned above can stretch that, so plan the project in weeks, not days.

No, living in the house or even being inside it during the lift isn't recommended. Your furniture and everything else can stay right where it is, so you only need somewhere to sleep for the lift days, not a moving truck.

In a city floodplain district, a new or substantially improved home needs its lowest floor, basement included, set one foot above the base flood elevation, which is the flood mark the rule starts from, so that's the height we plan the lift around. The city also requires a FEMA Elevation Certificate for that kind of work. Any enclosed space left below that height that isn't floodproofed is limited to parking, access and storage, and it has to use flood damage-resistant materials with at least two flood openings on different sides.

That's something to settle with the city before any work starts, and we find out which office covers your address and take care of the permit work for our part of the job. For a foundation repair permit, the city first wants a soil suitability report signed and sealed by a Virginia-licensed design professional, which gives the probable cause of the damage and how to fix it, though the city's list for that permit names underpinning, pilings and helical piers rather than raising a house. If your house is in a local historic district and the outside changes can be seen from a public way like the street, you'll also need a Certificate of Appropriateness from the Board of Architectural Review or the city's preservation staff, and if anything needs your signature, I tell you up front.

Usually it's the soil under the footings shifting, and the city's soil reports watch for expansive marine clay, a high water table, uncontrolled fill and soil that can't carry much weight. A Fairfax County guide explains that marine clay shrinks in dry periods, especially summer, and leaves gaps under the footings, so the house settles unevenly. That's why I want to know the cause before we talk about lifting anything.