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Most homeowners never think about what is holding their roof up until a contractor is standing in the attic with a flashlight, pointing at a cracked web member or a rusted truss plate. By then the questions come fast: what kind of frame is this, can it carry a tile roof, and does anything need an engineer.
Here is the short answer. The main types of roof trusses used on California homes are the king post, queen post, fink, howe, scissor, attic (room in attic), gable end, hip, mono and flat truss. Each one is a factory-built triangular frame of engineered lumber joined by galvanized truss plates, and each is designed for a specific span, ceiling shape and load. The right choice depends on your span, your desired ceiling, your roof covering weight and your local seismic and fire requirements.
At Clean Roofing, we have opened up attics on 1950s ranch homes in Santa Clara, 1970s tract houses in Sunnyvale and custom rebuilds in the Los Gatos hills. The framing tells a story about when the house was built and what it can safely carry today. This guide walks through that story so you can have a smarter conversation before you sign anything.
What Is a Roof Truss and How Is It Different From a Rafter?
A roof truss is a pre-engineered structural frame that carries roof loads across a span and transfers them down to the exterior walls, which is why interior walls under a trussed roof are usually non load bearing. Trusses are built in a plant to an engineered drawing, delivered as finished units and craned or carried into place.
Rafters are different. Stick framing is cut and assembled on site, board by board, using rafters and ceiling joists. Many older Bay Area homes, especially pre-1960s construction around Willow Glen and older parts of Palo Alto, are stick framed. Most homes built after the mid-1970s are trussed.
The practical differences matter more than the vocabulary:
- Trusses span farther, use less lumber, install faster and arrive with stamped engineering
- Trusses cannot be modified on site without engineering approval
- Rafters allow more attic storage and easier remodeling, but need interior bearing walls
- Rafters rely on the framer’s skill rather than a factory quality process
If you are weighing a full tear off, our guide on what is included in roof replacement explains where structural work fits into the scope.
Parts of a Roof Truss
Understanding the parts of a roof truss makes every inspection report readable, because a truss fails at its members and connections rather than as a whole unit. A truss is a closed triangle system where each piece does one job, and damage to any single piece changes how load travels through the rest.
| Component | What It Does | What Failure Looks Like |
|---|---|---|
| Top chord | Forms the sloped upper edges and carries the roof deck, underlayment and roof covering | Sagging between panel points, splitting near the peak |
| Bottom chord | Ties the base together, resists outward thrust and often carries the ceiling | Cracks at knots, deflection, notching by other trades |
| Webbing | Interior diagonal and vertical members that transfer load between chords | Buckled or missing webs, cut members near HVAC runs |
| King post or queen posts | Central vertical support between peak and bottom chord | Loosening at the plate, crushing at the bearing |
| Truss plate | Toothed galvanized steel connector pressed into every joint | Lifted teeth, rust staining, plates backing out |
| Heel | The point where top and bottom chord meet over the wall | Rot from chronic leaks at the eave, uplift separation |
| Bearing point | Where the truss sits on the top plate of the wall | Crushing, rotation, missing hurricane or seismic clips |
The most common problem we find in Bay Area attics is not a broken chord. It is a lifted truss plate or a web member cut by a previous contractor running a duct or a bath fan. Under the California Residential Code, truss members must not be cut, notched, drilled or otherwise altered without approval from a design professional. That single sentence has turned more than one cheap attic project into an engineering bill.
If your attic shows staining around the heels or the plates, start with our roof inspection checklist before assuming the damage is cosmetic.
The 10 Main Types of Roof Trusses Used in Residential Construction
Roof truss types differ by web pattern and chord geometry, and that geometry determines how far the truss can span and what ceiling shape it produces underneath. The table below is the fast comparison. The sections after it explain where each one actually shows up on California homes.
| Truss Type | Typical Residential Span | Ceiling It Creates | Best Suited For |
|---|---|---|---|
| King post | Up to about 16 ft | Flat, boxed in | Porches, garages, small additions, dormers |
| Queen post | About 16 to 32 ft | Flat, boxed in | Wider additions, simple rectangular homes |
| Fink (W truss) | About 16 to 33 ft | Flat, boxed in | The default for tract and production housing |
| Howe | About 20 to 40 ft | Flat, boxed in | Wider spans, heavier roof coverings |
| Scissor | About 20 to 40 ft | Vaulted or cathedral | Great rooms, modern remodels, open plans |
| Attic (room in attic) | About 24 to 40 ft | Habitable room inside the roof | Bonus rooms, offices, storage on tight lots |
| Gable end | Matches adjacent trusses | Closes the end wall | Both ends of a gable roof |
| Hip | Varies by hip set | Flat | Hip roofs, corner conditions, stepped sets |
| Mono | About 8 to 24 ft | Single slope | Lean to additions, porches, ADUs, sheds |
| Flat (parallel chord) | About 10 to 30 ft | Flat | Low slope sections, modern flat roof designs |
King Post Truss
The king post truss is the simplest design in the family: two top chords, one bottom chord and a single vertical post from the peak to the center of the bottom chord. It uses the least lumber of any truss type, which makes it the cheapest per unit.
In practice we see king post trusses over detached garages, covered patios and small rear additions across Campbell and Santa Clara. They are excellent up to roughly 16 feet and inefficient beyond that.
Queen Post Truss
A queen post truss replaces the single center post with two vertical posts and a horizontal straining beam between them. That extra geometry pushes the usable span meaningfully past the king post while keeping the design simple.
Queen post trusses are a sensible middle ground for a 20 to 30 foot addition where you do not need the ceiling opened up.
Fink Truss
The fink truss is the workhorse of American residential framing. Its webbing forms a W between the chords, which distributes load efficiently and uses very little material for the strength it delivers.
If your home was built in a Silicon Valley subdivision between the 1970s and today, there is a strong chance you are standing under fink trusses right now. They are cost effective and fast to install, with one trade off: the webbing chews up attic space, so storage is limited to the perimeter.
Howe Truss
A howe truss reverses the diagonal pattern of the fink, putting its diagonals in compression and its verticals in tension. The result handles wider spans and heavier roof coverings well.
This matters in California because roof covering weight is a structural question, not a style question. A concrete tile roof can weigh several times what an architectural composition shingle weighs per square. If you are considering cement tile roofing, the truss capacity has to be verified first.
Scissor Truss
A scissor truss has bottom chords that slope upward and cross near the center, producing a vaulted or cathedral ceiling without a ridge beam or interior posts. It is the single most requested truss in Bay Area remodels because it opens a room dramatically.
The trade offs are real. Scissor trusses cost more, they leave almost no attic space, and the reduced cavity depth makes attic insulation and ventilation harder to detail correctly. They also deflect more than a flat bottom chord truss, which is why drywall cracking at the ridge is a known scissor truss issue and why proper slip connections at the interior walls matter.
Attic Truss
An attic truss, also called a room in attic truss, is engineered with a clear rectangular void inside the webbing so the space becomes usable. The bottom chord is designed as a floor, not just a ceiling tie.
On expensive Peninsula lots where you cannot build out, building up inside the roof is often the cheapest square footage available. Attic trusses are heavier and require more careful crane staging, and the finished space usually needs sun tunnels or skylights to feel like a real room.
Gable End Truss
A gable end truss sits at each end of a gable roof and looks different from the trusses beside it: instead of diagonal webbing, it has closely spaced vertical studs, because it functions partly as a wall.
Gable end trusses are a known seismic weak point. In earthquake country the tall gable end can rack out of plane if it is not properly braced back into the roof diaphragm, and gable end bracing is one of the standard retrofit items California engineers specify.
Hip Truss
Hip trusses come as a stepped set of progressively shorter trusses that create the sloped ends of a hip roof. Instead of one repeated profile, you get a coordinated package with girder trusses carrying the concentrated loads.
Hip roofs perform well in wind and have no large gable wall to brace, but they cost more, complicate ventilation and offer less attic volume. Our overview of roofing types and materials covers how roof shape and covering choice interact.
Mono Truss
A mono truss is half a truss: a single slope from a high wall down to a low wall. Mono trusses are the standard answer for lean to additions, carports and the shed roof ADUs that have become common in Santa Clara County since the state loosened accessory dwelling unit rules.
Flat or Parallel Chord Truss
A flat truss has parallel top and bottom chords with webbing between, giving a level or very low slope plane. On homes it appears on modern architecture, on garage sections and on low slope tie ins, always paired with a membrane rather than shingles. If part of your home is low slope, flat roof system may be the right solution for protecting that area.
Types of Roof Trusses California Homes Actually Need
California adds a layer that national truss guides skip entirely: seismic demand, fire hardening and energy code, all of which change which truss design gets approved. Two identical floor plans, one in Los Angeles and one in Cupertino, will not get the same truss package.
Seismic Design Category Drives the Details
Most of coastal California, including Santa Clara County and the Peninsula, sits in high Seismic Design Categories under the California Building Code. That has direct consequences for roof framing:
- Trusses that carry lateral load into shear walls must be identified on the roof framing plan with the drag loads they are designed to carry
- Seismic bracing, blocking and diaphragm connections at the truss bearing points become part of the engineered design, not an afterthought
- Roof covering weight is limited in some braced wall conditions, because a heavy roof increases seismic mass at the highest point of the structure
This is the reason a lightweight composition or metal roof is sometimes recommended over concrete tile on older Bay Area homes. Weight at the top of a building behaves like a lever during shaking, which means reducing roof dead load reduces demand on everything below it.
Title 24 and the Raised Heel Truss
California’s Title 24 energy standards push for continuous, uncompressed insulation across the entire ceiling plane. A conventional truss heel pinches insulation to almost nothing right where the ceiling meets the exterior wall, which is exactly where heat moves fastest.
A raised heel truss, sometimes called an energy heel, lifts the top chord several inches at the bearing point to keep full insulation depth over the wall and preserve a clear ventilation path. It is a small upcharge at the truss plant and a permanent improvement in comfort. Pair it with correct intake and exhaust, as explained in our detailed guide to roof ventilation.
Wildland Urban Interface Areas
Homes in designated WUI zones, which include hillside neighborhoods above Los Gatos, Saratoga and parts of the Santa Cruz Mountains, fall under Chapter 7A ignition resistant construction requirements. Truss geometry affects this because the eave and heel condition is one of the most vulnerable ignition points on a house. Open eaves, vented soffits and exposed truss tails all need specific detailing.
One of our clients told us plainly that our crew made sure the assembly was WUI compliant so her insurance carrier would keep writing the policy. In the current California insurance market, that detail is not a technicality.
Solar Adds Load
Clean Roofing is one of the few certified Solar Roof installers in the Bay Area, and solar is where truss capacity gets overlooked most often. Panels, racking and attachment points add dead load and concentrated point loads to a frame that was engineered decades ago for a lighter covering.
Before a solar project goes on an older trussed roof, the framing should be evaluated. Adding load to a truss beyond its design capacity is not permitted without verification that the truss can support it.
How to Identify the Types of Trusses Roof Framing in Your Home Uses
You can usually identify your truss type from the attic in about ten minutes without touching anything structural. Look at the shape of the webbing, the slope of the bottom chord and the presence of metal plates at the joints.
Use this sequence:
- Look for truss plates: Toothed steel plates at every joint mean factory built trusses. Nailed or bolted connections with cut lumber usually mean site built rafters.
- Check the bottom chord: Level and continuous means a standard truss. Sloped and crossing means a scissor truss. A framed rectangular void means an attic truss.
- Read the web pattern: A W shape indicates a fink. Diagonals with verticals suggest a howe. A single center post is a king post.
- Look at the ceiling below: Vaulted ceilings on the top floor point to scissor trusses. Flat ceilings throughout point to standard trusses.
- Find the tag: Many trusses carry a manufacturer stamp or ink jet marking on a chord that identifies the plant, the design and sometimes the date.
- Photograph, do not modify: Send photos to a roofing contractor rather than cutting anything to get a better look.
If you find cracked members, lifted plates, daylight at the heel or moisture staining, compare what you are seeing against the signs of roof damage and get eyes on it before the rainy season.
Who Signs Off on Truss Design in California?
Truss design in California is handled as a deferred submittal, which means the truss package is engineered after the permit is issued rather than at initial plan check. Under CBC Section 107.3.4.1, deferring any submittal item requires prior approval from the building official.
The chain of responsibility works like this:
- The truss manufacturer prepares truss calculations and shop drawings
- A California licensed engineer or architect stamps, signs and dates those calculations
- The engineer or architect of record reviews the package for conformance with the overall structural design before it goes to the building department
- The building department reviews and approves it prior to installation
- Truss design itself follows ANSI/TPI 1, with temporary and permanent bracing per the industry BCSI guidance
For homeowners, the practical takeaway is simple. If a contractor proposes altering, removing or adding trusses without an engineered submittal, that is a permit problem and an insurance problem waiting to happen. Our approach to roof installation includes coordinating structural documentation, not working around it.
Our complete Saratoga residential rebuild case study shows what that coordination looks like on a full structural project.
Frequently Asked Questions
What are the most common types of roof truss in California homes?
The fink truss is the most common type of roof truss in California residential construction, especially in homes built from the 1970s onward. Scissor trusses appear in vaulted great rooms, attic trusses in bonus room designs, and gable end plus hip trusses at the roof perimeter. Older pre-1960s homes are frequently stick framed with rafters instead.
Can you remove or cut a roof truss to open up a room?
No, not without engineering. Truss members cannot be cut, notched, spliced or altered without approval from a design professional, because every member is carrying calculated load. Opening a ceiling under trusses generally requires a licensed engineer to design a modification, a permit, and often new headers or girder trusses to redistribute the load.
What is standard truss spacing on a residential roof?
Residential roof truss spacing is most commonly 24 inches on center, which balances lumber cost against sheathing thickness and load capacity. Some designs use 16 inches on center for heavier roof coverings or longer spans. Actual spacing is set by the truss engineering, not by a rule of thumb, and it must match the approved layout.
Do roof trusses need to be replaced when the roof is replaced?
Usually no. A roof replacement removes the covering, underlayment and often the sheathing, while the trusses remain. Trusses are replaced or repaired only when there is rot, fire damage, insect damage, prior unauthorized cutting or a load change such as switching to tile. Our crews evaluate the framing once the deck is exposed.
How long do roof trusses last?
Properly detailed roof trusses in a dry, well ventilated attic can last the life of the building, often well beyond 50 years, because the failure mode is moisture and alteration rather than age. Chronic leaks at the heel, condensation from poor ventilation and cut web members are what shorten truss life. See our guide on how long a roof lasts for covering lifespans.
Are trusses better than rafters for earthquake country?
Neither system is automatically better. Engineered trusses have the advantage of stamped calculations and factory consistency, while stick framing offers easier future modification. What matters seismically is the connection detailing: bracing, blocking, diaphragm nailing and a properly braced gable end wall.
Talk to a Bay Area Roofing Team That Reads the Framing First
Choosing between the types of roof trusses is a structural decision with a long shadow. It sets your ceiling height, your attic usability, your insulation performance, the roof coverings you can safely install and how your home behaves in an earthquake. Get it right at the framing stage and everything above it becomes easier and cheaper for decades.
Clean Roofing has served San Jose and the surrounding Bay Area since earning GAF Master Elite and Tesla certification, and our teams work daily in Sunnyvale, Palo Alto, Mountain View, Cupertino, Los Altos, Los Gatos and Santa Clara. We inspect the structure before we quote the covering, because a beautiful roof over compromised framing is a short term result.
If you are planning a replacement, an addition or a solar project, start with a free estimate. Run your numbers through our roofing calculator, explore our residential roofing services, or contact us and we will get someone in your attic with a flashlight and an honest opinion.
