I spent three days in Portland at the International Mass Timber Conference, March 31 to April 2, 2026. Thousands of people. Fabricators, engineers, architects, developers, forest products companies, code officials.
The thing I kept hearing in the hallway conversations was some version of the same problem. A developer had designed a building in concrete or steel, gotten to design development, and then asked whether they could switch to mass timber. The answer was usually yes. The follow-up answer was usually that it would cost more than the concrete building they already had.
That is the whole issue. Mass timber gets treated like a finish selection. It is a structural system, a fire strategy, a moisture strategy, and a procurement strategy, and all four of those get locked in at schematic whether you make the decision consciously or not.
I have been developing in California and the western US for 25 years. I have watched this same mistake in other forms. Someone treats a system decision as a material decision and pays for the difference at bid.
Here is what actually has to be settled before schematic closes.
The fire-rating path drives everything else
Most owners want mass timber because they want to see the wood. Exposed timber is the product. It is also the most expensive decision to make late.
Under the 2021 IBC you have three tall mass timber types. Type IV-C allows the most exposed timber. IV-B allows a limited percentage of exposed surface. IV-A requires essentially everything encapsulated in noncombustible protection, typically multiple layers of Type X gypsum. The heights, areas, and allowable exposure differ across all three.
If you go exposed, the structure has to be sized for char. Wood chars at a predictable rate and the char layer insulates the sound wood behind it. The design method adds sacrificial material so that after the required fire duration, the remaining cross section still carries the load. The standard nominal char rate for softwood is about 0.65 mm per minute, with an effective rate near 0.7 mm per minute once you account for the loss of strength in the heated zone below the char line. For a two-hour rating, you are adding a meaningful sacrificial thickness on every exposed face.
That is a real number. Bigger members. Sometimes a thicker panel, sometimes an extra lamination, sometimes a different layup entirely.
If you go encapsulated instead, you keep the members smaller, but you add gypsum layers, the labor to hang and finish them, and you lose the reason you wanted timber. You now have a wood building nobody can see.
Neither answer is wrong. Deciding at design development is wrong, because member sizing, panel layup, and the entire fabrication order depend on it.
A grid drawn for concrete wastes timber
CLT and glulam have their own efficient spans. Panels want to run in one direction and they want to land on supports at spacings that match how the panel is manufactured and shipped.
Concrete and steel grids do not naturally line up with those spans. If you drop timber into a bay that was drawn for a flat plate, you get panels that are thicker than they need to be, more laminations than you need, and fabrication waste on every cut.
The grid is a schematic decision. Once the core, the parking layout below, and the unit plan are set, the grid is effectively frozen. You cannot re-space columns in design development without redrawing the building.
Connections are the cost center
The panels are usually not where the budget goes sideways. Connections are.
Every connection is steel, fasteners, and labor, and there are thousands of them. Concealed connections cost more than exposed plates but preserve the look you are paying for. Seismic requirements in the western US add hold-downs, diaphragm chords and collectors, and load paths that have to be worked out in the panel layout rather than bolted on afterward.
Connection strategy is where a timber budget is actually won or lost. It is also the thing a developer never asks about until the shop drawing phase, which is far too late to change the geometry that drives it.
Panels on a wet site are a schedule problem
Wood gets wet. That is manageable. Wood that stays wet is not.
Panels arrive with a factory finish and a moisture content in a narrow band. On site they see weather. The industry answer is a written moisture management plan: factory-applied sealants and membranes on panel edges and faces, wrapped and elevated storage, a lift-and-set sequence that gets the roof and weather barrier on fast, drainage details at every horizontal surface, and moisture content readings logged before you close anything up.
The reason to care is not housekeeping. It is warranty and schedule. Fabricators write moisture requirements into their terms. Panels that sit exposed and take on water can cup, delaminate at the glue line, or show staining that you cannot sand out on an exposed ceiling. Replacing a panel means a new fabrication run and a crane day, and the fabrication run is on a lead time you do not control. The delivery side of this is covered in mass timber delivery risk on Durata Advisory.
Sequencing for weather is a schematic conversation, because it determines the erection sequence, which determines the crane plan, which determines the site logistics that your civil and your general contractor are drawing right now.
The fabricator belongs in the room during schematic
This is the part that surprises developers most.
A mass timber fabricator is not a vendor you buy from at bid. Fabrication is CNC work driven by a model, and the model has to be complete. Every penetration, every hanger, every sprinkler drop, every conduit route through a panel is cut in the shop.
In stick framing, a plumber drills a hole. In a CLT panel, that hole was decided months earlier, drawn in the model, and cut by a machine in a plant. Field modification of a structural panel is a request for information, an engineering review, and sometimes a rejection.
That pulls MEP coordination and acoustic assembly decisions far earlier than a developer plans for. Acoustics in particular. A bare CLT floor does not meet residential impact sound requirements on its own. You need a topping assembly, and the topping adds weight and thickness that feed straight back into structural sizing and floor-to-floor height. Which feeds back into the grid. Which is a schematic decision.
Then there is the calendar. Shop drawings, fabricator review, and a production slot mean the design freeze on structure lands well before a developer expects it. Order in the wrong window and you are waiting on a plant that is booked.
Where it does pencil
Mass timber does not automatically pencil. Anyone who tells you it always does is selling something.
It pencils when erection speed converts to real carry savings, when the smaller crew and the dry, quiet site are worth something on a tight urban lot, when the exposed structure is the finish and you delete a ceiling assembly, and when the finished product commands rent or absorption you can defend in your comps.
It stops penciling when you decide late, encapsulate everything, and pay a premium for a wood building nobody sees.
The check to run this week
Put these questions to your team before schematic design closes. Each one has to come back with an answer you can write down.
- To the architect and code consultant: Which construction type are we, IV-A, IV-B, or IV-C, and exactly what percentage of timber surface is exposed? The answer is a number and a code path, not "we're planning on exposed."
- To the structural engineer: Given that fire strategy, what is the sacrificial char thickness on every exposed face, and what did it do to member sizes and panel layup versus the encapsulated version? The answer is two sizing schedules side by side.
- To the structural engineer and architect together: Is this grid drawn for timber spans or inherited from a concrete or steel layout, and what does the panel schedule look like at the current bay? The answer is a panel layout with span directions on it.
- To the fabricator, engaged now: What is your current lead time from design freeze to delivery, what date do you need shop drawings, and what is written in your terms about site moisture and storage? The answer is three dates and a paragraph.
- To the general contractor: What is the erection sequence and how many days are panels exposed before the roof and weather barrier are on? The answer is a sequence and a day count, not "we'll tarp it."
- To the MEP engineers: Are every penetration and hanger through a panel in the model, and who signs off before fabrication? The answer is a coordinated model and a name.
If your team cannot answer all six, you do not have a mass timber project yet. You have a concrete project with a wood idea attached to it, and the idea is going to get value-engineered out in eight months.
Where does this project break, and how early can we catch it? On timber, it breaks at schematic. Which of those six answers can your team produce by Friday?