How Gambrel Roof Trusses Maximize Interior Space
Key Takeaways:
Featuring steep lower roof slopes with greater clearance at height, the purpose of gambrel trusses is to maximize usable interior space. These types of trusses are commonly found in:
- Barns
- Garages
- Workshops
- Residential lofts
Builders and homeowners who want extra room at the top prefer this type of truss due to its increased storage capacity and ability to create wide-span spaces without additional support.
Of all the roof truss types commonly used in construction, gambrel trusses are most commonly preferred when the objective is to maximize interior space.
However, for new contractors, this raises a couple of questions – why gambrel trusses? How do they help? What purpose do they serve?
In today’s blog, Fonthill Lumber Inc, Ontario truss engineers with 75 years of experience, will attempt to answer every question contractors may have about gambrel trusses in great detail. Let’s begin.
What Is A Gambrel Roof Truss?
A type of truss most commonly used to build a wide variety of spacious structures, gambrel roof trusses typically feature slopes on each side to create extra space. Generally, the lower slope of this framing system will be steeper than its upper section. This helps in the creation of more height and room.
Key structural components of this truss type include:
- Top chords
- Bottom chords
- Internal webbing systems
Each of these elements works together to help in the even distribution of loads while maximizing interior space.
The major difference between gambrel roof trusses and other types is that the former is generally the better choice for creating an additional floor on the roof. Its basic structure provides more headroom, which is why it is commonly used to build:
- Barns
- Garages
- Storage buildings
- Cabins
- Homes with lofts
The gambrel variety is the most efficient engineered roof truss system when it comes to optimizing usable space underneath the roof.
How Gambrel Roof Trusses Maximize Interior Space
The gambrel truss design is known for creating additional headroom – especially when compared with any other truss type. How it manages to do that boils down to its basic structure. Let us explain:
Steeper lower slope for extra room
The lower section of this roof type features a very steep rise. This allows adjoining walls to extend higher than they otherwise would, thus increasing ceiling height while contributing to the size of the usable floor area.
Expanded attic and loft space
Since there is more room underneath the roof, gambrel trusses are better suited to home designs that require lofts or additional storage space in the attic. This also prevents costly expansions later on.
Gambrel trusses can be used to efficiently frame external structures as well, such as barns, garages, and workshops – basically any space that requires unobstructed storage and more open interiors.
More space-saving than traditional trusses
The best part about gambrel trusses is that they can increase space under the roof without increasing the footprint of the entire building. This space-saving nature equips them with a couple of distinct advantages:
- More headroom on the upper floor
- Greater attic storage space
- Potential to create a loft
- Reduced need for external extensions
However, if gambrel trusses are not appropriate for your project, it makes sense to learn about different roof truss designs so you can make an informed decision.
Common Types Of Gambrel Roof Trusses
What most contractors just starting do not know is that gambrel trusses can also be of several types. We have covered the common ones below:
Standard Gambrel Trusses
Agricultural and residential structures depend on standard gambrel trusses. Since their attic storage requirements are low, the standard variety proves to be a more cost-efficient choice in the short and long run.
Attic Gambrel Trusses
Slightly more complex in design and scope, this type is specifically engineered to make the space under the ceiling more habitable and functional. Attic trusses are a staple in country homes, cottages, and even workshops that make use of the loft as extra storage or living space.
Storage Gambrel Trusses
True to their name, storage gambrel trusses are designed to maximize open attic volume. This allows owners to effectively use the area for housing equipment, seasonal items, or other items that are not needed regularly.
Gambrel Trusses With Wide Spans
Wide-span gambrel trusses are a fixture in large barns and commercial agricultural buildings. Their extra-wide spans create huge, uninterrupted interior spaces that can be used to store large quantities of individual items or heavy equipment and machinery.
Custom Engineered Gambrel Trusses
Ultimately, complex commercial or residential developments demand the use of custom-engineered trusses. Since their snow loads, span requirements, and architectural preferences go beyond what standard trusses can fulfil, it makes more economical sense to customize their truss systems rather than modifying existing ones to suit their needs.
Most builders resort to custom trusses in the following cases:
- The project’s spans exceed standard dimensions
- The design demands additional attic space
- Increased storage loads change structural requirements
- Ontario regulations around snow loads require reinforced framing
In any case, specialized residential roof truss systems optimize space usage while ensuring the project’s unique load requirements are fully met.
Best Applications For Gambrel Roof Trusses
These residential roof trusses are actually used in commercial buildings too. In fact, their core applications stretch far and wide to cover a wide variety of builds, notable among them including:
Barns and agricultural buildings
Both these structures require large storage spaces to keep crops, grains, and other local produce. Gambrel trusses excel here. In fact, they are also known as barn-style roof trusses because of their frequent use in barns and agricultural buildings. They maximize interior storage capacity, serving as the best roof choice.
Detached garages and workshops
With this roof design, garages and workshops get extra overhead storage space without being forced to expand the horizontal footprint of the entire building.
Residential homes with loft spaces
Gambrel roof framing has become an integral part of many modern homes, thanks to its ability to create bonus rooms, lofts, and expanded attics that can store more than they would be able to with standard roofing.
Storage builds and sheds
Individual storage units are likely to use gambrel systems because of their ability to maximize vertical storage without taking too much square footage. They are more cost-effective for smaller builds.
Cottage and cabin construction
Cottages, cabins, and lodges are frequently used as summer homes or vacation stays, which means their demand for usable living space is quite high. That is why gambrel roof profiles are commonly used here, so individual guests or residents can enjoy their roominess.
Step-By-Step Construction Process Of Gambrel Roof Trusses
Careful planning is the stepping stone to installing gambrel trusses the right way. Contractors must balance span performance, storage requirements, and structural safety to ensure the final build can stand the test of time and regular use.
Step 1: Determine span and roof pitch requirements
Like any truss installation project, builders must cover the basics first. Starting by understanding the building's dimensions and roofing requirements can help in the engineering of precise trusses. The storage goals of the project should be factored in right at the beginning.
Step 2: Select the right gambrel truss design
While the storage requirements of the space are the most major factor in determining the appropriate gambrel truss design for any construction project, a couple of other critical factors should be accounted for as well. These include the building type and its expected loads. This ensures the selected truss type offers lasting strength and durability.
Step 3: Engineer support and load calculations
Truss configurations should be based on actual structural calculations to ensure long-term durability. These calculations should factor in the weight of roofing materials, snow loads, wind exposure, and the roof’s span requirements.
Step 4: Fabrication and delivery
The next step involves entrusting the manufacturing of trusses to professionals. Builders must share the building’s plans and roofing requirements with engineers for precise fabrication. Once built as per specifications, completed trusses will be delivered onsite, ready for final installation.
Step 5: Bracing and installation
Lifting equipment is required for the accurate placement of trusses so they can be installed properly. Temporary bracing ensures perfect alignment before they can be permanently secured. Temporary bracing can also prevent unnecessary truss repositioning and related damage.
Step 6: Complete roof sheathing and finishing
At this stage, permanent bracing is installed to secure trusses firmly in place. Once done, the process of sheathing and application of roofing materials can commence. Adding finishing touches is the final step in the process of gambrel roof truss installation.
When it comes to installing gambrel trusses, the goal should be to choose the right truss type that meets the load, storage, span, and design requirements of the project.
Structural Limitations Of Gambrel Roof Trusses
Like any framing system, gambrel roof trusses have their own set of limitations, which might not make them the best choice for certain projects.
Load distribution considerations
Because of their unique shape, varying roof slopes are typical for gambrel trusses. This makes planning for loads complex. When designing these trusses, it is critical to ensure the system itself supports the even distribution of loads across to prevent straining individual members.
Weather and snow load challenges
The snow season in Ontario is long and capable of exerting immense stress on roofing systems. Since gambrel trusses feature shallow sections on the top, they are more prone to snow strain and may require extra reinforcing to survive multiple winters.
Maintenance and design limitations
Complex by design, the geometry of this roof type complicates the installation process and increases long-term maintenance requirements – especially when compared with standard or simpler truss systems.
Conclusion: Optimizing Interior Space With Gambrel Trusses
Limitations aside, gambrel roof trusses are still excellent for homes and buildings that want the maximum interior usable space possible without increasing the footprint of the entire structure. Be it barns or garages, cabins or cottages, these trusses are efficient, expansive, and flexible enough to suit a wide variety of projects.
To get structurally strong roofing systems, builders need to choose their truss manufacturer carefully. Fonthill Lumber Inc. has 75 years of experience in manufacturing strong and stable trusses that exemplify precision and flexibility in Ontario. Contact us to order custom trusses of any size, type, or span.
FAQs
What is a gambrel roof truss?
It is a type of roof truss system that is primarily made up of two slopes – one upper and one lower – to maximize interior space. The lower slope tends to be steeper than the upper one.
Why are gambrel roof trusses popular for barns?
Since they allow the efficient construction of wide open storage spaces, gambrel trusses are commonly used to build barns.
How much attic space can a gambrel roof provide?
The exact dimensions depend on the span and pitch of the project. However, their attic space is considerably larger than that of standard trusses.
Are gambrel roof trusses suitable for residential homes?
Yes. In fact, they are widely used to build lofts, bonus rooms, and attics in residential buildings.
What are the disadvantages of gambrel roof trusses?
Complex engineering and additional reinforcement to handle Ontario snow loads are the main limitations of gambrel trusses.
