Designing the structural skeleton of a new house is not something you can hand off halfway and expect a clean result. The structural design process of a residential building from A to Z runs from the first soil boring to the last connection detail stamped on a permit set, and every phase along the way affects whether the home performs the way it should for the next 50 to 100 years. Homeowners and builders in the Denver metro area and across the Front Range often come to us after the architect has already produced a floor plan, wanting to know what happens next, who touches the project, and how long it will actually take before a shovel hits the ground.
This guide walks through that sequence in the order it actually happens in a working engineering office: pre-design data gathering, load determination, foundation selection, framing and lateral system design, coordination with the architect, permit submission, and the questions that come up once framing crews are on site. None of this replaces a conversation with your engineer about your specific lot and design, but it should make that conversation a lot more productive.
What Happens Before Design Even Starts
Before an engineer sizes a single beam, two things need to exist: a geotechnical report and a reasonably complete architectural plan set. Skipping either one is the single most common reason residential structural design projects stall out or require expensive rework later.
The geotechnical, or soils, report is produced by a separate geotechnical engineering firm that drills test borings or digs test pits on the lot, logs the soil profile, and runs laboratory tests for moisture content, plasticity, and expansion potential. That report gives the structural engineer the allowable soil bearing pressure, expansive soil classification, groundwater depth if encountered, and a recommended foundation type. Without it, a structural engineer is guessing at bearing capacity, and guessing on a foundation is not something a responsible firm does on a house where people will be living above a basement wall for decades.
Documents the Structural Engineer Needs From the Architect
At minimum, the engineer needs a floor plan for each level, a roof plan, building elevations, and a few key sections showing ceiling heights and roof pitches. These documents establish tributary areas, span lengths, roof slope (which matters for snow drift calculations), and any large openings the architect is hoping to achieve, such as a wall of glass or a vaulted great room.
It also helps enormously if the architect flags mechanical equipment locations early — rooftop units, tankless water heaters, or a heavy soaking tub on a second floor can all become point loads that need to be traced down through the framing to the foundation. A plan set that arrives without window and door schedules, or without a clear roof plan, usually bounces back with a round of clarifying questions before structural work can start in earnest, which adds time nobody wants to lose. Architects familiar with this handoff tend to build in a short review period specifically for the structural engineer’s comments before finalizing their own drawings.
Establishing Design Loads in the Residential Structural Design Process
Every structural member in a house is sized to resist a combination of loads, and getting these numbers right is the technical backbone of the entire design. These are not arbitrary figures — they come from the applicable building code and ASCE 7, the national standard for minimum design loads referenced by the International Building Code (IBC) and the International Residential Code (IRC).
Dead load covers the permanent weight of the structure itself: framing lumber, roofing, drywall, flooring, and fixed mechanical equipment. Live load accounts for the weight of people, furniture, and movable objects — codes specify different live load values for bedrooms, living areas, decks, and stairs because occupancy patterns differ. Snow load, wind load, and seismic load are environmental loads that vary by geographic location, and this is where a house in Denver or Evergreen gets designed very differently than a house in Phoenix or Miami.
Snow, Wind, and Seismic Loads in Residential Structural Design
Snow load calculations start with the ground snow load value published for the jurisdiction, then get adjusted for roof slope, exposure to wind, and thermal factors — a flat roof behind a taller adjacent wall, for instance, can accumulate a drift load several times higher than the open-field ground snow value. Wind load design considers the basic wind speed for the region along with exposure category and the building’s height and shape, since a tall, narrow home with large gable ends behaves very differently under wind pressure than a low, hip-roofed ranch.
Seismic design in Colorado is a lighter consideration than in California or the Pacific Northwest, but it is not ignored — the Front Range sits in a low-to-moderate seismic zone, and engineers still check lateral force paths, connection hardware, and shear wall capacity against the applicable seismic design category. All of these loads eventually get combined using the load combinations prescribed in ASCE 7, and the governing combination for each member — not just the worst single load — determines its final size.
Choosing the Foundation Type for a New House
The geotechnical report’s bearing capacity and soil classification largely dictate which foundation system makes sense, but the engineer still has to weigh that recommendation against the architect’s layout, the site’s slope, and the owner’s plans for a basement. The three most common residential options are slab-on-grade, crawl space, and full basement, each with different footing, wall, and moisture-management details.
On lots with steep grade changes, which show up constantly along the foothills west of Denver, a walk-out basement lets the lower level open directly to the backyard on the downhill side while still bearing on competent soil or rock at the uphill side. Where expansive clay is present — common across much of the Denver metro, Highlands Ranch, Castle Rock, and Colorado Springs — the engineer may detail a structural floor system over a crawl space (a “structural slab” or void-formed slab) rather than a slab resting directly on grade, specifically to keep the floor isolated from soil movement.
Slab, Crawl Space, and Basement Decisions for Expansive Soils
When expansive soils are confirmed by the geotechnical report, the foundation wall reinforcing, footing depth, and floor system all get revisited. A basement wall retaining expansive clay typically needs more horizontal reinforcing steel than one retaining ordinary granular backfill, and the footing design often incorporates a void space or compressible material under grade beams to relieve uplift pressure as the clay swells.
Drilled piers or caissons extending down to bedrock or a stable bearing stratum are another common solution on sites with deep expansive clay or fill soils, transferring the building’s weight past the problem layer entirely. The geotechnical engineer specifies the required pier depth and allowable end-bearing or skin-friction values, and the structural engineer designs the grade beams spanning between piers. Homeowners dealing with a home that already shows cracking or heaving from soil movement may find it useful to review the signs covered in our residential structural engineer denver guide, which gets into foundation distress indicators in more depth.
Framing and Lateral System Design for a New Home
Once the foundation is settled, attention shifts to the vertical framing — the floor joists, wall studs, roof rafters or trusses, and the beams and headers that carry loads around openings. This is also where the lateral force-resisting system gets established: shear walls, hold-downs, and diaphragm nailing patterns that keep the house from racking sideways under wind or seismic load.
Most single-family homes in Colorado use conventional wood light-frame construction, with engineered wood products — LVL (laminated veneer lumber), PSL, or glulam beams — specified wherever a span exceeds what dimensional lumber can handle or where a large opening removes a bearing wall. Steel beams or columns show up less often in standard wood-framed houses, but they appear regularly in homes with long clear spans, cantilevered sections, or a request for minimal visible structure, such as a steel flitch beam hidden inside a wood header.
Sizing Beams and Headers in the Residential Design Process
A beam or header is sized by calculating the tributary load it carries — essentially, the portion of roof, floor, or wall weight that funnels down onto that member — and then checking bending, shear, and deflection against the allowable capacity of the chosen material and size. Deflection limits matter as much as strength limits in residential work; a beam that is strong enough to not break can still deflect enough to crack drywall or create a bouncy floor if it is undersized for stiffness.
Every beam needs a clear load path down to the foundation, which means the engineer also has to check the posts, studs, or columns beneath it, and ultimately the footing supporting that point load. This is where coordination with the architectural plan becomes critical — if a post lands in the middle of a kitchen island in the framing plan but the architect’s cabinetry layout didn’t anticipate it, something has to give, and it is far cheaper to resolve that conflict on paper than after the wall is framed. Homes with large additions or room reconfigurations run into this constantly, which is part of why a structural engineer experienced with home additions is worth involving early in a remodel-driven design.
Construction Documents and the Permit Drawing Set
The construction document phase is where every calculation gets translated into drawings a builder can actually use in the field. The final structural set typically includes a foundation plan with footing sizes and reinforcing schedules, framing plans for each floor and the roof, a series of structural details showing connections and waterproofing, and a general notes sheet listing the codes, material strengths, and design criteria used.
Alongside the drawings sits the calculation package — sometimes called the calc book — which documents the dead, live, snow, wind, and seismic loads used, the governing load combinations, and the analysis behind every beam, column, shear wall, and footing shown on the plans. Plan reviewers at city and county building departments routinely request this package, especially for anything outside prescriptive IRC limits, such as a long cantilever, an unusual roof shape, or a steel moment frame.
Permit Review and Plan Check
Local building departments across the Denver metro — including Denver Community Planning and Development, and the building departments in Jefferson, Arapahoe, and Douglas counties — review submitted structural drawings against the adopted edition of the IBC or IRC along with any local amendments before issuing a permit. Plan check comments typically come back as a list of specific corrections: a missing hold-down schedule, a beam that needs a revised bearing detail, or a request to clarify the soil bearing value referenced on the foundation plan.
Turnaround time for plan review varies by jurisdiction and current submittal volume, and it is worth asking the local building department directly rather than assuming a fixed number of weeks. Once comments are addressed and the revised set is resubmitted, the department issues the permit and framing can legally begin. Builders who have already lined up a Structural Inspection schedule with their engineer at this stage tend to move through the special inspection requirements on the permit more smoothly once construction starts.
Construction-Phase Questions in Residential Structural Design
Structural design work does not end when the permit is issued. Framers, concrete crews, and steel erectors regularly run into field conditions that do not match the drawings exactly — a utility line conflicts with a footing location, a delivered beam is the wrong grade, or a framer wants to relocate a point load to simplify a stair layout. Each of these needs a quick response from the engineer of record, usually in the form of a field clarification or a formal revision if the change affects load paths.
Special inspections are another construction-phase requirement that catches some owners off guard. Many jurisdictions require third-party special inspection of items like high-strength bolting, welding, epoxy anchors, and certain foundation reinforcing placements, as outlined in IBC Chapter 17. Coordinating these inspections before the concrete truck shows up, rather than after, avoids the costly scenario of exposing rebar or anchor bolts that have already been poured over.
Coordinating Changes During New Construction Design
Field changes during framing should always route back through the structural engineer before the crew proceeds, even when the change looks minor from the carpenter’s point of view. Moving a beam six inches to clear a duct chase can shift its bearing point off a foundation wall or a doubled stud pack designed for exactly that location, and the engineer needs to verify the new load path before the framing gets covered by insulation and drywall.
Builders who keep the structural engineer looped into the project’s RFI process, rather than treating the permit set as the final word, tend to close out projects with far fewer disputes at final inspection. A Construction Inspection scheduled at key milestones — foundation reinforcing before the pour, framing before drywall — gives everyone a documented record that the work matches the approved drawings.
Colorado-Specific Factors for a New House
Three site conditions come up on nearly every new home project across the Front Range, and each one shapes the structural design in a specific way. Frost depth requirements, set by the local building department, determine the minimum depth footings must be placed below finished grade to avoid frost heave damaging the foundation over winter freeze-thaw cycles — this depth varies by jurisdiction and elevation, so the engineer confirms the specific requirement with the local building department rather than relying on a blanket statewide number.
Expansive clay soils are widespread across the Denver metro, the I-25 corridor, and much of the eastern plains, and as covered earlier in the foundation section, these soils drive decisions on structural floor systems, void spaces beneath grade beams, and reinforcing in foundation walls. A geotechnical report specific to the lot is the only reliable way to know the swell potential and plasticity index for a given site, since expansion behavior can differ noticeably between neighboring lots depending on the depth and composition of the clay layer.
Snow and Site Conditions Affecting Residential Structural Design
Ground snow loads increase with elevation across Colorado, which means a home in the foothills or mountain communities west of Denver typically carries a heavier roof snow load requirement than a comparable home on the plains, and roof framing, truss design, and snow retention details are adjusted accordingly. Roof geometry matters just as much as elevation — valleys, multiple roof planes at different heights, and areas below a taller adjacent roof section all create drift conditions that the engineer has to check against the applicable code provisions for unbalanced and drift loading.
Steep lots in communities like Golden, Morrison, and parts of unincorporated Jefferson County also bring retaining wall and grading considerations into the structural scope, since cutting into a hillside to create a buildable pad often requires engineered retaining structures to hold back the cut slope. Homeowners planning a build on sloped terrain may want to look at our Retaining Wall Design page alongside their foundation planning, since the two are frequently designed together on hillside lots.
Typical Timeline and Mistakes to Avoid
In qualitative terms, a straightforward custom home moves through schematic structural input, design development, and a full construction document set over a period that stretches from a few weeks to a couple of months, depending heavily on how quickly the architectural plans stabilize and how many rounds of revision the design goes through. Projects with complex rooflines, long-span great rooms, or unusual foundation conditions on sloped or expansive-soil lots generally take longer, simply because more iterations are needed to resolve load paths cleanly.
The most expensive mistake homeowners and builders make is involving the structural engineer too late — after the architectural plans are “finished” and the owner is ready to break ground. Structural input early in schematic design, while walls and openings are still flexible on paper, almost always costs less than redesigning a beam or relocating a column after the architect has already finalized cabinetry, plumbing, and electrical layouts around the original plan.
Common Errors in the Residential Structural Design Process
Skipping or delaying the geotechnical report is the second most common error, since foundation decisions made without soil data frequently have to be revisited once the report arrives, sometimes after footings have already been laid out. Another recurring issue is treating structural drawings as optional for additions or renovations — a load-bearing wall removed without an engineered header and verified load path is one of the most frequent causes of sagging floors and cracked finishes we get called to investigate after the fact.
Underestimating snow drift loads on complex rooflines, failing to detail moisture protection at foundation walls in expansive soil areas, and not coordinating mechanical equipment weights with the framing plan round out the list of avoidable problems. Each of these is straightforward to address when caught during design, and considerably more disruptive and costly to fix once walls are closed up.
Site Problems That Cause Redesigns
One pattern causes redesigns often enough to mention: a framing crew standing in front of a beam pocket that does not line up with the plan because a duct run or a plumbing stack was added after the structural drawings were finalized. The fix is rarely difficult on its own, but it is far cheaper to coordinate mechanical routing with the structural plan before the drawings are stamped than to modify framing in the field.
Expansive clay sites are a reason to treat the geotechnical report as the first document to read on a new project, not the last. Foundation plans are sometimes redrawn after a soils report comes back showing a higher swell potential than the preliminary assumption, and the cost of that change is lowest when the report arrives before design starts.
Frequently Asked Questions About Structural Design for a New House
Who is involved in designing a new home’s structure?
A typical new home project involves the homeowner, the architect, a geotechnical engineer, a structural engineer, and eventually the general contractor and framing crew who execute the design in the field. The structural engineer works primarily from the architect’s plans and the geotechnical report, coordinating closely with both throughout design development.
On larger or more complex homes, a civil engineer may also be involved for site grading and drainage, and a truss manufacturer’s engineer often designs the roof trusses themselves based on load criteria the structural engineer specifies on the drawings. All of these parties need to be reviewing a consistent, current set of plans — outdated architectural sheets circulating alongside updated structural sheets is a frequent source of field confusion.
When should a structural engineer be brought into new construction design?
A structural engineer should be brought in as soon as the architect has a workable schematic floor plan and roof concept, well before the design is considered final. This lets the engineer flag feasibility issues — an oversized cantilever, a column landing in an awkward spot, a roof shape that will drive up snow drift loads — while the architectural plan is still easy to adjust.
Waiting until construction documents are “done” to bring in structural input often forces compromises that could have been avoided, such as a dropped ceiling to conceal a deeper-than-expected beam, or a relocated window to make room for a hold-down post. Early coordination is consistently the cheaper and faster path.
What is the difference between a geotechnical report and a structural calculation package?
A geotechnical report documents the soil and site conditions — bearing capacity, expansion potential, groundwater, and a recommended foundation type — and is produced by a geotechnical engineering firm before structural design begins. A structural calculation package documents the engineer’s analysis of the building itself, showing how loads are calculated and how each beam, column, wall, and footing is sized to resist them.
The structural engineer relies directly on the geotechnical report’s bearing and expansion data as an input to the foundation calculations, so the two documents are closely linked but serve distinct purposes and are prepared by different licensed professionals.
Can I skip a geotechnical report on a small residential project?
Some jurisdictions allow use of a presumptive soil bearing value for very limited, prescriptive residential projects without a site-specific geotechnical report, but this depends entirely on the local building department’s adopted code amendments and the project’s scope. Given how common expansive clay is across the Denver metro, relying on an assumed bearing value rather than a site-specific report carries real risk on anything beyond the simplest prescriptive scope.
For a full new home, most structural engineers and most local jurisdictions will require or strongly recommend a geotechnical report regardless of whether the code technically permits an exception, simply because the cost of the report is small compared to the c
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