For superior energy-efficiency, modern houses are increasingly designed over stem walls with slabs. These “slab” foundations are less costly and can manage slops as effectively as crawl spaces, etc.

However, alternative foundation systems are also available upon request, as follows:

1. Slab on grade conversions (for warm climates): $100

2. Raft foundations (super insulated): $100

3. Crawl spaces (vented): $100

4. Crawl spaces (sealed with radon mitigation): $200

5. Basements: $300 + additional fees for related design, such as stairs, interior finishing, etc.

6. Concrete Post & Pier: $200 (not generally recommended for larger designs)

7. Helical Piers: $200 (not generally recommended for larger designs)

Please note that modification requests are the cost of a plan plus the cost of any modification work.