Substantial Improvement / Substantial Damage Requirements

What is substantial improvement?

The National Flood Insurance Program (NFIP) requires that any reconstruction rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50% of the market value of the structure before the start of construction of the improvement, must conform or meet the same construction requirements as a new building and be constructed above the minimum Base Flood Elevation (BFE) listed on the city’s Flood Insurance Rate Map (FIRM).

What is substantial damage?

Substantial damage means damage of any origin sustained by a building or structure when the cost of restoring the building to its pre-damaged condition would equal or exceed 50 % of the market value of the building before the damage occurred. Substantial damage is determined regardless of the actual repair work performed.

Building Permit Requirements

The city of Grand Prairie requires by ordinance that any substantial improvement or substantial damage improvement must have a building permit. Permit information can be obtained at the Building Inspections Division website or by calling 972-237-8230.