These questions of design sequence get into some very sticky territory quickly, with a lot of possibility for time and money wasted all around. In my earlier days I don't know how often I put hours and hours into quotes and changes to quotes, only to have them pull the plug, leaving me out that time. It would also be irresponsible to put the customer in a situation where they are investing time, energy, and emotion into a design that they can never bring to fruition.
I have a way that I approach it, which seems to work pretty well all around. I prefer to be pretty actively involved in the design process, along with an architect, TF engineer, and the homeowner. Most frequently, prospective customers tend to contact me first, before they have selected an architect or any other contractors. I can pretty quickly establish the basics of what they are envisioning in a house, at least enough to say tell them what ballpark they are in for the whole house, and enough to give them a budgetary estimate on frame and enclosure, which is usually within 10%. I do all the above for free and probably have about 4hrs of conversations into this.
If we are looking like it's in the realm of possibility, it's time to get an architect involved. The architect(s) will usually do a consultation, give a bid for services, and take a look at making sure project budget looks feasible.
If all goes well to this point I will ask the customer to sign a Memorandum of Understanding. This assigns them an approximate spot on my schedule and gives a brief overview of the project. I also get a small down payment at this point which goes toward planning costs, usually about 2% of my package cost. This is deducted from the down payment when the project is fully defined and has come to real contract. This down payment is stated to revert to them if I welch on the project and if they bail I keep whatever amount that I have in time invested. This puts a little skin in the game for the customer but not so much that they are overexposed.
At this point, we start the full 3 way conversation between customer, timber framer, and architect. The timber frame informs design and layout, as well as vice versa, so there is lots of modeling, problem solving, and back and forth all around to ensure that all parties are happy, and we come out with a good build-able, within budget design.
At the end of this process, we have a full set of plans by which an exact project cost can be determined. At this point I will either come to full contract with the customer and get the production process ramped up, or if for some reason, the customer chooses to abandon the project, I leave with my design expenses paid for. Although, I have really never had anyone do that.
The method I have been using seems to keep everything nice and transparent while limiting exposure for everyone. I don't mind spending a few hours talking to a prospective client and putting together a rough model, even if it doesn't happen. I figure that it's reasonable for a customer to get a free initial consultation and estimate.
To put it succinctly, the customer should not proceed without a decent assurance that the chosen direction is within budget, but the customer is not going to be able to nail down exact project pricing without paying for some design work.


I must say I'm pretty dubious about the existence of any per sq. ft. TF price. At least not without so many qualifiers as to make it meaningless. People are constantly asking me, "what is your sq. ft. price for a timber frame". My answer is, "Anywhere from $20 to $100."