A clear starting range
The price of a prefab ADU is different. The entry model has a price of less than 60,000 and it might have more than 200,000. Delivery, foundation, utilities, permits and finishes, and the total will most typically fall between approximately 100,000 and 300,000.
What adds to the price
Costs have been divided into a limited number of categories; the unit itself, site prep, permits and design, utility hookups and interior finishes. Some thousands of dollars can be added to permits and design. The largest part of the bill is normally composed of materials and labor. Site work, utility connections will be a serious addition particularly when you require a new septic system or power trenching.
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Three simple budget paths
Basic kit path (lowest cost)
Purchase a small factory facility and do site work and most in-house. You save on the building fee, but have to pay foundation, delivery, hookup, and permits. This route would be less than 100,000 in low cost regions.
The most prevalent is the balanced build path.
Purchase a mid-size ADU and pay contractors to do the site, hook-ups and finish-up. This provides quality predictability and has fewer surprises. With this strategy, many homeowners will be between the 120-220K range.
Full-service route (more expensive)
Select a completed unit of one of the companies that deal with permits, crane delivery, and connections. You sacrifice a price in the convenience. The cost of the all-inclusive prices of bigger two-bedroom units can also be as high as $200,000 to $350,000 or above in high-cost cities.
Quick example you can follow
E.g., a 400 sq ft prefab unit that costs 60,000. Include foundation and site preparation 25,000, utilities 15,000, permit and design 7,000 and interior finish 10,000. Total about $117,000. Use this as a model. Depending on place and state of lot, your numbers will vary.
Short before you spend checklist
- Check local Zoning and permit fees.
- Obtain three estimates of site work.
- Ask the suppliers about what is in and what is not in their price.
- Establish the transport logistics and crane requirements.
- Reserve 10-20 percent contingency on the unexpected.
How to shop smart
ADU prefab homes can be searched and compared to what is standard. There are those companies that sell the structure alone and there are those that install it. Request references on new and recent projects. Seek in particular the most favorable prefab unit deals with explicit, line-item pricing.
Final thought
Prefab ADU will be able to save time and reduce part of the costs but it will not eliminate site and permit expense. Determine then how much you desire to take care of yourself and what portion you wish to have incorporated in the price. That option determines the basic kit route, the middle route, or the full-service route. These are the quotes that are local and the above simple checklist, start with them and you will create a realistic budget that you can rely on.
