What Is Rough Ground (Sub Frame) in the Fenestration Industry? Uses, Benefits & Challenges

Homeowners, architects and contractors involved in window installations often encounter the growing trend toward rough ground or subframe installations. But what does it mean, and how does it help?

Rough ground or subframe serves as a connecting element between the wall and the final installation, ensuring the door or window fits correctly and stays well-insulated. It helps with correct alignment, precise installation and final product protection, making it popular in the fenestration industry.

Ready to know more? Here are some benefits and practical challenges with this modern solution.

What Is Rough Ground or Sub Frame in Fenestration?

A rough ground, also known as a sub-frame, is an aluminium rectangular tube that serves as the foundation for window and door installations. They are used during the early construction phase to ensure the main frame fits accurately and securely.

Usually available in various dimensions and thicknesses, these sub-frames can be customized to suit different project needs and site conditions.

• Made from durable aluminium, commonly 20x75 mm to 25x125 mm in size;
• Thickness ranges from 1.0 mm to 2.0 mm.
• Customisable to match architectural and functional requirements;
• Provides alignment, support, and long-term stability for mainframes.

Where Is Rough Framing Typically Used?

Rough framing, also known as sub-framing, plays a crucial role during building and renovation. It provides the foundational support needed to ensure that windows and doors are installed accurately, aligned properly, and remain structurally secure over time. To understand what to look for when evaluating window installation work, check out our guide on the things to consider when choosing a window installation company.

Here’s where it’s commonly used:

• New Construction

In new construction projects, rough framing is used right from the beginning to define structural openings for windows and doors. It ensures that all apertures conform to standardised dimensions, making installation easier later.

Why? - Setting clear boundaries early helps maintain consistency across the project and prevents measurement issues down the line.

• Remodelling and Additions

During renovation or extension work, rough framing plays an important role in aligning new window or door openings with the existing structure. It helps maintain visual uniformity and structural consistency, especially in older buildings where walls and measurements may have shifted over time.

Why? - This makes it easier to blend new sections into the original layout seamlessly.

• Special Applications

Rough framing is also used in special or custom architectural scenarios, such as skylights, curtain walls or boutique façades. In these cases, it provides added support and can be tailored to fit non-standard shapes or sizes.

Why? - This flexibility makes it an ideal solution when design creativity or unique functional requirements come into play.

Why Is Rough Framing Called “Rough”?

The word “rough” refers to the early, unfinished stage of framing that happens before the visible parts, like glass, plaster or trim, are added.

It’s the hidden structure that holds everything in place, ensuring your windows or doors are properly aligned and secure. Though you won’t see it in the final design, it plays a critical role in long-term performance.

Framing Elements Found in Different Parts of a House

Every part of a home relies on specific framing elements that ensure structural strength and balance. Each type of frame plays a unique role in supporting the overall design and functionality.

• Wall Frames: These include studs, sills, and headers that form the backbone of walls and provide support for window and door openings.
• Roof Frames: Made up of rafters and trusses, these frames maintain the roof’s shape and evenly distribute weight to prevent structural strain.
• Floor Frames: Comprising joists and beams, these frames support the flooring system and ensure stability throughout the building.
• Window & Door Frames (Sub Frames): Sub frames are especially important for fenestration. They ensure accurate fitment, proper sealing, and long-term stability for windows and doors.

Key Benefits of Using Rough Ground (Sub Frame)

• Standardisation of Aperture Sizes: Rough ground ensures that every window or door opening is uniform in size, improving quality control and helping manage silicone bite more efficiently.
• Faster Installation and Time Savings: Since aperture preparation and window manufacturing can run in parallelly, overall installation time is reduced.
• Improved Watertightness and Sealing Performance: Even sealing around the frame edges prevents gaps and water leakage, ensuring long-term protection.
• Cost Savings Through Material Optimisation:Standardisation reduces silicone use and on-site waste, improving material efficiency.
• Enhanced Aesthetic Finishing: Smooth, uniform apertures create a cleaner, more refined final appearance.

Common Challenges in Using Rough Ground Systems

While rough ground systems offer several benefits, they also come with practical challenges.

• Transporting or handling subframes can cause bending or damage.
• Improper fastener fixing or differences in thermal expansion may cause cracks or visual defects.
• Moisture buildup from the absence of ventilation channels can compromise structural integrity and lead to improper installation.
• Corrosion around screws is also a common concern.

How to Overcome Them?

• Carefully assess and choose compatible materials to balance temperature variations.
• Use corrosion-resistant fasteners.
• Ensure precise aperture alignment.
• Include ventilation channels for better moisture control.
• Conduct regular maintenance checks for long-lasting performance.

Conclusion

Rough ground or sub-frame installation may seem like a small step, but it plays a big role in achieving durable, watertight and perfectly aligned windows and doors.

With AIS Windows, you get expert engineering and precision framing solutions, ensuring long-lasting performance and aesthetic excellence. If you wish to learn more about Rough Ground Fenestration for your project, get in touch with our experts today.