Mat and Jessica Robbins built a 2,600-square-foot timber frame home in Durango, Colorado, and the number matters less than how they got there. With three growing children they needed four bedrooms, but when they sat down to plan, square footage was not the priority. Jessica asked for three things: a huge bathtub, a huge window over the kitchen sink, and a porch for drinking tea. Mat, a timber framer since 2000, wanted the house as efficient as possible. The result follows the principles of the Not So Big House, and it now reads as a working example of small timber home design from a Colorado retreat: hold the footprint, spend the savings on craft.
Timber Frame Structure That Doubles as Finish
The Robbins build homes with traditional techniques: frames joined with mortise and tenon joinery, pinned with hickory pegs, and no metal brackets, nails, or bolts. The exposed frame is simultaneously structure and finish, which is the biggest cost lever in a timber home.
How the Frame Goes Together
A timber frame transfers loads through interlocking joinery rather than metal connectors. The mortise is cut into one member, the tenon on the mating member, and a hickory peg locks the joint. Because the connections are mechanical and the members are large-section timbers, the frame can be left exposed, saving the drywall, furring, and finish work that a stud wall requires on both faces.
Why Exposed Structure Saves Money
Every surface the frame provides is a surface the owner does not pay a carpenter to build. The full comparison of structural timber engineering options, from sawn lumber and glulam to cross-laminated timber and heavy timber construction, shows why exposed heavy timber consistently shifts money out of the finish trades and into the structure itself.
Passive Solar and the Masonry Heater
The home sits on a passive solar slab with a passive solar design, and its centerpiece is a Russian stove. A fire burns in the lower chamber, the masonry mass above absorbs the heat, and that mass radiates warmth into the house over many hours. The stove works so well that the Robbins essentially never turn on the radiant heat system, even on most winter days.
Designing for Solar Gain
Passive solar starts with orientation. The long axis of the house runs east-west, glazing concentrates on the south face, and the slab stores daytime heat and releases it at night. Overhangs shade the glass in summer when the sun rides high, and low winter sun reaches deep into the slab. The design is a geometry problem solved before a single wall is framed.
Masonry Heaters and Thermal Mass
A masonry heater differs from a conventional fireplace because the firebox and flue are sized to burn hot and fast while the surrounding mass stores the energy. One or two firings a day can warm a well-insulated home through most of a winter day, and the even radiant heat keeps floors and walls comfortable instead of cycling air. The stove in the Robbins home is also the visual anchor of the main floor, with the handcrafted stair wrapped around it.
The envelope does the other half of the work. High-performance windows, dense insulation, and careful air sealing keep the heat the stove produces inside the shell, which is what lets a single firing last through a winter night. The Robbins sized the glazing for solar gain rather than view alone, and the slab acts as a battery that smooths the temperature swing between day and night.
Spending Square Footage on What Matters
The Not So Big approach treats every square foot as a budget line. The Robbins kept the house at 2,600 square feet when a conventional plan for a family of five might have run 3,500 or more, and the savings funded the rooms and details they actually wanted. The same judgment separates a well-designed large home from a poorly planned McMansion, where square footage gets added without a plan for how it will be used.
Three Wants That Drove the Plan
- A huge bathtub, because the bath is where Jessica unwinds
- A big window at the dishwashing station, turning a daily chore into a view
- A porch sized for tea and conversation, not decoration
Each want targeted a room the family used daily. Bedrooms stayed modest because sleeping does not need a sitting area. The plan spends its square footage on the kitchen, the bath, and the porch, the spaces where the family actually gathers.
Where the Savings Show Up
Holding the size down funded a spiral stair, an interior stained glass window, a custom range hood and kitchen cabinets, decorative tile laid in special patterns, and acid-etched steel siding on the second floor. These are the touches that make the house one of a kind, and they exist because the owners chose fewer square feet instead of more of the same.
Budgeting: Square Footage vs. Craftsmanship
Mat’s budgeting rule is blunt: everybody has a budget, and if the only goal is maximizing space, the craftsman side of the budget gets cut. Keep the square footage down and there is room to put a little extra here and a little extra there. The trade-off is not between cheap and expensive; it is between more of the same and less of something better.
Where the Money Goes
| Budget decision | Maximize-space approach | Small-and-green approach |
|---|---|---|
| Footprint | Build the largest house the loan allows | Hold size and fund craft |
| Structure | Frame hidden behind drywall | Exposed timber frame as finish |
| Heating | Furnace plus ductwork | Passive solar slab plus masonry heater |
| Finishes | Builder-grade in every room | Custom details in a few key rooms |
| Room sizing | Similar rooms throughout | Oversize the rooms used daily |
Cost per Square Foot Math
Total cost and cost per square foot move in opposite directions. A larger house spreads fixed costs like site work and permits over more area, but it adds structure, finishes, and mechanicals at the margin. A smaller house carries a higher per-foot rate and a lower total price, which is what matters to a buyer with a hard budget. The same math shows up in regional markets where affordable small towns let buyers spend on the house rather than the location, the pattern visible in Tennessee’s Cumberland Plateau where entry prices stay low enough to fund upgrades.
Site and Regional Trade-Offs
Where the house goes changes what it costs to build green. Durango sits at about 6,500 feet with cold winters and intense sun, which rewards solar orientation and thermal mass but demands a tight envelope. The same design moved to a humid lowland needs different moisture control, and a coastal site different wind detailing.
Climate, Altitude, and Orientation
Altitude changes the performance of almost everything: air is thinner, solar gain is stronger, and nights are colder. Builders in mountain towns size heating systems for the design temperature, not the average, and passive solar works best when the site has clear southern exposure with no tall trees shading the glass.
Site work should be verified with a winter visit. Snow depth, the angle of the sun at the winter solstice, and the location of utility lines all show up differently in January than in July. A quick solar-path check done on the actual site confirms which roof faces will collect sun and which will sit in shade, and it costs nothing except a day of driving.
Regional Cost Variations
Land and labor costs vary more between regions than materials do. Garden enthusiasts get their own version of the trade-off in Oklahoma’s Green Country, where rich soil and affordable housing make the land cheap and the construction budget the variable to manage. Comparing regions on land price, labor rates, and climate before committing to a site pays for itself.
Choosing a Wood Construction System
Before the design work starts, the construction system has to be settled, because it drives the budget, the schedule, and the look. The choice between a log home and a timber frame home comes down to what the owner wants the structure to do: log walls carry both enclosure and finish in one material, while a timber frame carries the load and leaves the infill to other systems.
What Each System Delivers
- Timber frame: exposed posts and beams, infill walls, flexible floor plans
- Log: solid wood walls, high thermal mass, a single-material shell
- Conventional framing: lowest material cost, finish required everywhere
- Engineered systems: glulam and CLT for longer spans and panelized speed
The Robbins picked the timber frame because the exposed structure gave them the warmth they wanted without paying for it twice. Buyers who run the same comparison against their own budget, climate, and aesthetic land on the system that fits, and the small-and-green approach works in any of them. A properly detailed timber frame also ages well: it sheds water, breathes, and can be repaired member by member, which matters to owners who plan to stay in the house through retirement.