Density – Rules of Thumb?
During the initial stage of land development, a developer needs to conduct some fairly thoughtful analysis as to the lot sizes and product. I like to think the first priority is the market analysis, with the idea being that you want to make sure a project is marketable. And then comes the product analysis in trying to optimize the right combination of pricing, costs, and density.
With experience, you should have a decent feel for how many lots or units per acre for various products. The actual density will be confirmed once some site planning is completed, and this actual density can be affected by inefficient parcel dimensions, terrain, city zoning, common area requirements, and other factors.
The following are some rules of thumb for various lot sizes and products. Just a quick note to point out is that while an acre is 43,560 square feet, some portion of that acre needs to be used for streets and other common area. As one example below, achieving three 10,000 square foot lots per acre only totals to 30,000 square feet, meaning the rest of the acre is taken up by the streets and common area.
- 10,000 sf lots: 3 per acre
- 7,000 sf lots: 4 per acre
- 5,000 sf lots: 5 per acre
- 4,000 sf lots: 7 per acre
- 3,000 sf lots: 10 per acre
- Two-Story Townhomes: 15 per acre
- Three-Story Townhomes: 20 per acre
- Three-Story Apartments: 28 per acre
Urban products that utilize concrete parking structures can vary from 50 to 100 units per acre, but that is a bigger discussion that involves stories, garage levels, and square footage.
Please feel free to share your comments and questions below.