I wish that here were legal definitions of 'custom' and 'semi-custom'. To me, custom means a unique design especially suited to the clients and their land. Design, construction, finishes, appliances, fixtures, etc., would be whatever the client wanted (or could afford). If I were entering into a contract for a true custom home, I would want to be able to specify everything, and source it wherever I wanted to if I were so inclined.

I can see a contractor charging a fee for some things that the client sources. In our house I used antique doors, antique light fixtures, and an antique bathroom sink. All of these required extra work, in some case, considerable extra work. Also, the contractor likely has certain sources where they get a discount. If they get a discount on Kohler toilets, and you want a Toto, that's money out of their pocket. In other words- you CAN have what you want- for a price.

I used to have my own manufacturing business. I marked up the cost of all components, and sometimes that was the only profit I made on a project. If a customer came to me with cheap, imported components to save money, I'd have to charge more, and wouldn't be able to confidently warranty the results. Suppose your builder uses a quality window, like Marvin. You want to save money and buy cheap vinyl seconds from Bubba's Bargain Basement. Who is on the hook when the windows fail?

A true custom house is always going to cost more. XYZ Builders crank out tract homes by the thousands. All of the bugs have been worked out. In a custom home, everything is (or can be) unique, which requires all of the trades to be more skilled, and be more careful. Issues crop up that no one saw coming, and have to be dealt with.

I've rambled a lot here- hope some of it is helpful. I built my own house, so I know first-hand how much longer it takes for custom 'everything'. Our little house would have been ridiculously expensive had I paid a contractor to build it.

A true custom home is one where every single thing is unique to your home. It's a home that hasn't been built before so as mush said, it requires more thought and skill to make it.

A semi custom home is one where you pick from the builders stock plans, and then pick your finishes, either from his/her available choices or your own with an upcharge.

I did remodeling on a custom basis. The customer bought the material and I installed them. I had recommendations for materials I knew were of good quality, but the customer made the decisions and the purchases.

That meant I had to spend extra time learning, in some cases, how to install the material, since most manufacturers have specific instructions.

Example: Customer wanted a specific color/style of manufactured flooring in a bathroom. They wanted it, in part, because the product was advertised as being ClicLock, easy to install. I knew, from experience and simple common sense that flooring in baths, kitchens, and laundries needed to be glued to minimize water damage. The seller's rep said that gluing was not necessary----the manufacturer's instructions specified gluing in those uses and even specified the brand of glue. Had to special order the glue---took extra time, plus what time I spent correcting the seller.

Then found out the pieces did not easily click together with the glue because the glue was too thick. Which meant each piece had to be clamped to fit properly.

That turned a half day job into a three week nightmare.

Just a small example of why builders use trusted materials.

Semi-custom is what a spec house used to be. Now, builders don't want their money tied up in spec houses, so they build them under contract. In the end, it's the same thing - about as far from "custom" as one can get.

What does custom vs. semi-custom mean to you?

As others have already said, to many of us custom means a unique, one-of-a-kind design with fixtures, fittings and finishes designed for this design only and build by a general contractor who does nothing by one-of-a-kind custom homes.

Semi-custom, to many of us, means a plan repeated by a builder many times before, with the consumer able to pick from a menu of finishes, or given allowances for their own picks of some fixtures, fittings and finishes.

Do you understand the two different approaches and why they may have different costs?

What is a custom tailored suit to you? One that you buy off the rack at Men’s Wearhouse and that is then taken in at the waist and the sleeves lengthened to fit only you? It’s now not an off the rack suit that would roughly fit someone else of similar build. Those really long arms that you have made sure of that. Is that a custom or semi custom suit? Does it matter if you buy it from James Davis instead? Or have it altered in house or by a third party tailor? No, because it was made in Vietnam to begin with for some generic 44 long.

Or, is a custom suit one that starts with your complete body measures, and a history of your weight? Then you take a look at some already created examples to see if you like a two button or three, wide or narrow lapels, or a subtle herringbone vs a classic pinstripe? And than the tailor creates a pattern just for you, based on details, like those really long arms and your history of fluctuating 10 pounds from December to April. It’s made in a muslin to check the fit and make any final adjustments. Now you pick your woolen, or your linen, or gabardine. But only after the fit of the suit was right for the body that would wear it.

Which approach requires more man hours? Which approach is more expensive?

In the end, “custom” is a completely unregulated term that hacks have been bastardizing to try to make themselves seem more than they are. People mentally assign quality as a synonym to custom. Custom is NOT a synonym for quality. You can have very poor quality things made especially for you just like you could very high quality items. When you can go to Burger King and get a custom Whopper, that word has lost its real world meaning.

The financial form of your contract have zero bearing on whether the house is custom or semi custom. Each builder has found a way to charge for their work that makes them money. Some do it by a fair price on top of all labor and materials. Some do it by a low bid for genetic materials and then making it up on change orders. If you don’t like how someone prices their work, find someone that you do. But remember that the more risk that a builder assumes, the higher the price he needs to assume that risk.

I remember my many trips to Beijing and in off hours looking at "custom" watches and "custom" suits...

This is a semi-custom:

Semantics. Doesn't matter.

Well, for the OP's purpose in shopping for a builder, it matters somewhat. At least in what she should ask when vetting them. One of those questions ought to be to ask a "custom home builder" what he means by that. In my case, it means I can hand my builder a bag of vintage milk glass knobs for the cabinets and he'll go... "Ummm... OK, then." And if I want beech hardwood floors and his usual supplier doesn't carry them - if I can point him at a supplier, and we both decide we're comfortable with that supplier, then I get my beech floors.

(Poor man, I keep handing him vintage bits and off-the-wall ideas. Though it must be said he seems to be rather enjoying himself.)

Does a "true" custom builder accede to the client's every request, including hiring their idiot half nephew on their mother's side to build the "custom" kitchen cabinets, all of which arrive a month late and none of which are quite square?

Decide how you want to proceed and work with a compatible builder, however they categorize themselves.

"Custom" and "semi-custom" is, to me, mostly a matter of semantics. Many builders have their own definitions for what they do, so you just need to make your decisions based on what you want, and what the various builders are telling you.

For example, we are in the process of building a new house. It would be called, by everyone, a custom build. And to answer your question about why they would always be more expensive, it's because generally speaking, a "custom house" means that everything is, or could be, decided specifically for what the homeowner wants.

But that varies. In our case, as part of our decision-making on which builder to use, the builder told us what materials and spec he usually uses, and what that type of houses usually costs, per square foot. That helped us decide that this builder could build a house (designed for us by one of the architect that this builder works with, whose work we like) that's in the price range we want to be at. We are able and welcome to choose whatever we want, but that will affect the price (both increasing and decreasing the price, but we all know which way the price generally moves). We haven't discussed who would buy fixtures, etc, but I would prefer that he do so. And I'm sure he has better deals for the vendors and trades that he usually works with, and using the type of materials that he usually uses, which would factor into which materials he uses.

"Custom" and "semi-custom" is, to me, mostly a matter of semantics. Many builders have their own definitions for what they do, so you just need to make your decisions based on what you want, and what the various builders are telling you.

Semantics yes, but given that, as lexma writes, many builders have their own definitions for what they do (some do use "semi-custom" instead of "spec" because it sounds better), one of the most important things you can do is get those definitions and make sure that you as the owner, any builders you are interviewing and soliciting bids from -- and any architect involved -- are all speaking the same language. Which means agreeing on the various definitions and terms. And if you're not sure about something, ask : ) .

Custom for me included materials and techniques in building science that was above and beyond what the code required. I wanted advanced hurricane/wind resistance. I wanted wind resistant windows and doors with unbreakable (not really) glass. Excellent sealing and insulation. My carpenter was adding some shelving to my garage one day and I asked why it had to have the more costly rounded piece on the shelf and he said all of my builder's houses required it. And all of my closets are shelved wonderfully following sketches I drew for our needs. My builder has certain ways he wants AC vents to be placed and I was not limited to put wall switches on the nearest stud. If I wanted it 3' over to the right, he blocked it to allow that. Speaking of blocking, I have that in most of my walls to facilitate special hand rails or heavy attachments. My garage is finished sheetrock with a 10' ceiling just like the rest of the downstairs. Custom also can include level 5 finished smooth walls and ceilings. It also included paints in whatever color and finish I wanted. No limitations. So custom means what ever you and your builder agree on and/or his standards. I always say "This is the opposite of a starter house - it's a finisher house!"