Hi Scott,
That's a great question. Let me give it a shot and see if I can shed some light on the subject since I'm both an investor and licensed GC in Florida and have built upwards of 20 new construction houses in the last couple years.
I also just finished a free blueprint for building a house in FL and my goal is keep adding more details to each step. And I'm keeping it free for everyone who's interested to read and maybe collaborate on and refine it.
There are two types of cost in development:
a. Development cost: this cost fluctuate a lot based on the site. The cost starts with
1.) plan cost (survey, civil engineer, site plan, architect, structural engineer, mechanical/electrical/plumbing (short for MEP) plans, etc.). The most important plan in this part is the site plan. Understand exactly how big is the structure, how are you orient the structural, what's the access situation, parking situation, driveway, landscape, and waste water management. In the residential world, some requirements are relaxed comparing to commercial so it's up to you whether you want to spend the money to have a better planning versus skip the planning and perform the work impromptu. For example, MEP plans are not required for permitting, but if you are designing a complicated house, having a MEP plan certainly helps to guide the trades to know exactly how and where to install the fixtures, versus something they have to figure it out impromptu in the field. Based on my experience, the better I plan it out, the less issues I faced in the field. So sometimes if I have to spend a few hundred bucks to have the architect draw out the details to help the tradesman later down the road, I will.
2.) local municipalities fees. They are application fees, plan review fees, maybe/maybe not impact fees (tens of thousands of dollars paid to the local government so you can develop a raw land), permitting fees, rezoning fees if rezoning is required.
3.) Public utility taps (public water and sewer taps) or on-site utilities (well water and septic system). These cost can go as high as $40k if you end up in an area that requires ATU septic system, or as low as almost nothing, if you purchased a property with existing water/sewer taps paid for by the previous owner. Now you see why builders can't just give you a price/sq ft.
4.) Site work (Land clearing/demolition/fill dirt/lot grading/old well and/or septic abandonment/culvert). Another item that can run you upwards of $30k if you ended up buying a sink hole that needs tons of fill dirt. But at the minimum, to get the site ready to build on an even flat land, it's good to budget $10k for total sitework.
5.) Environmental. Hope you didn't buy a wetland and need to do wetland mitigation. But it's another cost to consider for developers.
6.) Management fee. Everything I mentioned above, you can do it yourself or hire a professional to do it for you. There is no license in development so anybody can do it. But if you decide to hire a professional to do it for you, then that's the cost you have to factor in.
I think I've pretty covered most of the major costs on the development site for the residential space before you start construction. Almost all builders can do the development work for you, but that's a unknown cost and nobody can give you an accurate quote without studying the site. So it's unreasonable to ask for a general price because any number that someone gives you site unseen is either: so low that the builder will eat the cost, lucky and spot on, so high the builder covers the worst case scenario but the investor would over pay if there are savings because certain things I mentioned above are applicable.
Once the development phase is completed minus the last part which is pull permit for the build, you have a building blue print in your hand, you can send the site plan and building plans out to your local builders for bids on the build. This is where you should get fairly accurate estimate. As long as you have your selections and finishes annotated on the plan.
b. The vertical cost (construction cost) is consisted of material + labor + contingencies (surprises) + overhead + profit. Most professional builders in the area who have built project recently should have a good idea of material and labor price to build a house. Unless you are hiring a mega builder who gets insane discount on labor and material, most of your medium size or small size builders should have access to similar cost labor and material. If you hired a builder who only build one or two houses a year, aren't that proficient at it, may have high contingencies built in so the builder still makes money if things didn't go as planned, or a proficient builder who builds 10 houses a month should have very small contingencies. If you hire a big name brand builder you main have to pay more on overhead (project manager, superintendent, heavy equipment and machines) and their profit versus if you hire a small builder, the overhead could be almost nothing, and lastly, if you are a good investor/customer, you maybe able to get a better deal (a builder is willing to build the house for less profit). As a good investor, always always keep this in mind, especially when you get an insane deal, how is the service provider give me an insane below market deal and still keep a successful business running? Is this a sustainable operation? Or is it short lived?
This is the ideal world. This is assuming the builder who reviewed your plan has accounted for everything and give you a price that will cover their cost and make a profit in doing so. If the builder miscalculated or overlooked on certain items, now they are making very little/nothing/lose money, either they will honor their word and still finish the house for you at a loss, or they just stop showing up to your job. That's where bad experience/nightmare come in.
Lastly, to answer your question, to build a basically designed, square/rectangular house without crazy jigsaw puzzled cuts on roof, the following price is a good competitive construction only price for what you need to do:
Around $165 per sq ft on conditioned space (for an average 1200 to 1800 sq ft house, 8-9ft high ceiling, everything is investor grade finishes), $90-100 per sq ft for garages/unconditioned storage, $60 per sq ft for porches/opened spaces.
Hope this helps with your questions.
