Hi: There is a wide range of costs per square foot for construction, depending on a lot of things. Is the property level or not? Rocky? What quality finishes will you use inside or out? Usually construction costs are approximately 50% for exterior, including: foundations, walls, roofs, windows, siding, etc. & 50% for interior: including sheetrock, electric, plumbing, HVAC, lights, tile, flooring, appliances, doors, etc. Those costs can be further whittled down to approximately half for materials & half for labor. It's hard to save money in big chunks when you're doing contruction, but it's easy to save a few hundred here & there. And that adds up. Contractors with big mortgages & fancy cars usually charge more than those without. Paying more money doesn't always equal better quality work. I'd say that the minimum would probably be approx. $150 psf & the max could be over $1,000 psf. We can help you with that. Just call my office: 914-273-9688 with any questions. Sincerely, Michael Levy, Principal Broker, Grand Lux Realty. BTW, we're looking for more agents & offer a 70% commission split with no fees. If you know anybody who might be interested I'll pay you up to $1,000 each for your agent recruits. Thanks.