Fire Blocking Soffits 101: A Comprehensive Guide

Fire blocking soffits are a crucial aspect of a building's fire safety, and understanding how they work is essential for homeowners and builders alike. Soffits are the underside of a building's roof overhang, and they can be vulnerable to fire spread.

A soffit is typically made of wood or composite materials, which can be prone to ignition from embers or flames. In fact, wood soffits can ignite at temperatures as low as 400°F (204°C).

Fire blocking soffits are designed to prevent the spread of fire from one area of the building to another. By installing fire-resistant materials, such as metal or gypsum, in the soffit, you can create a barrier that will slow down or stop the spread of fire.

In areas with high fire risk, such as near wood-burning stoves or fireplaces, it's especially important to install fire blocking soffits to minimize the risk of fire spread.

Fire blocking soffits are a crucial component in preventing fire from spreading through a building's exterior. They are essentially a barrier that blocks the flow of flames and hot gases.

In residential construction, fire blocking soffits are typically installed in exterior walls, usually under eaves and around windows and doors. This is where they can be most effective in containing fires.

Fire blocking soffits can be made from a variety of materials, including fiberglass, mineral wool, or spray foam. These materials are designed to be non-combustible and can withstand high temperatures.

In many jurisdictions, building codes require fire blocking soffits to be installed in certain areas, such as near fireplaces and chimneys. This is to prevent fires from spreading quickly through the building.

The International Building Code (IBC) requires fire blocking soffits to be installed in exterior walls with combustible materials. This includes wood and other materials that can catch fire easily.

Fire blocking soffits can be installed during new construction or as a retrofit to existing buildings. They are an important safety feature that can help save lives and property in the event of a fire.

Fire blocking soffits requires careful consideration during the design and installation process. You can't simply ignore the mechanicals in a soffit when it comes to firestopping.

In many cases, soffits are designed to be accessible for maintenance and repairs, which can make firestopping more feasible. However, it's essential to assess the specific situation and determine the best approach.

The goal of firestopping a soffit is to prevent the spread of fire and smoke, and there are various materials and methods that can be used to achieve this.

When designing a soffit, it's essential to consider firestopping to prevent the spread of fire between dwellings. A soffit slab can be designed to fill the void within the soffit, providing a fire, thermal, and acoustic barrier.

The barrier is typically manufactured from rock fibre mineral wool, with a reinforced foil facing to ensure an effective smoke barrier is created. This type of barrier can be easily created to form an effective barrier at the junction.

For soffits with mechanicals, a specialized solution is required. One option is a soffit slab designed to fill the void within the soffit, providing a fire, thermal, and acoustic barrier between dwellings.

Soffit slabs can be manufactured to fit most roof pitches and soffit dimensions, making them a convenient solution for many applications. They are also made from foil-faced mineral wool, which provides excellent thermal and acoustic properties.

To ensure compliance with building codes, it's essential to check with the inspector before installing any fireblocking product that isn't on the approved list. This includes materials like mineral wool or fiberglass insulation, which may not be approved in all jurisdictions.

Code requires that chimneys and vents have an air space between them and the combustible floors and ceilings they pass through. This air space must be fireblocked with non-combustible material that's securely fastened in place.

For masonry chimneys, common methods for fireblocking include "L"s fabricated out of 26-ga. or thicker metal, or strips of cement millboard. These methods can be used to prevent flame and combustion products from racing up alongside vents and chimneys.

Here are some common materials used for fireblocking:

The ARC Soffit Slab is designed to fill the void within the soffit, providing a fire, thermal and acoustic barrier between dwellings.

This product is specifically designed to provide a fire, thermal and acoustic barrier, making it an essential component in building design.

The ARC Soffit Slab is designed to be used in conjunction with other products, such as Mineral wool fire-stopping (Pr_25_80_81_51).

Here are some examples of products that can be used in conjunction with the ARC Soffit Slab:

The ARC Soffit Slab is designed to provide a barrier between dwellings, and it's essential to choose the right products to work with it effectively.

Fire blocking soffits requires careful consideration of the materials and finishes used. Standard Finishes include G90 Galvanized, Stainless, Copper, and Bonderized.

For the foundation vents, eave vents, and soffit vents, Vulcan Vent offers a range of options. The NFVA (Nominal Fire Vent Area) for each model varies, with options like VE3522FB (41 square inches) and VFS814FB (62 square inches).

Some Vulcan Vent models are designed for cross-application, such as the 3.5" x 22" and 5.5" x 22" foam back flange set back 1-1/2" models. These models can be used in multiple categories due to their versatility.

Fireblocking materials must meet specific code requirements. According to the International Residential Code, acceptable fireblocking materials include nominal 2-in. lumber, double layer of nominal 1-in. lumber with offset lap joints, and 23⁄32-in. or thicker wood structural panels (OSB; plywood).

Standard Finishes are a crucial aspect of Vulcan Vent products, and there are several options to choose from. G90 Galvanized, Stainless, Copper, and Bonderized are all available finishes.

The G90 Galvanized finish is a popular choice for its durability and resistance to corrosion. It's a great option for areas with high humidity or exposure to the elements.

Stainless steel is another excellent finish, offering a sleek and modern look while providing excellent corrosion resistance. It's perfect for coastal or marine environments.

Copper is a stylish and durable finish that adds a touch of elegance to any building. It's a great choice for historic or traditional buildings.

Bonderized is a special finish that provides a durable and corrosion-resistant coating. It's a great option for areas with high humidity or exposure to the elements.

Here's a summary of the available Standard Finishes:

These finishes are not only functional but also add a touch of style to any building. Whether you're looking for durability, corrosion resistance, or a sleek look, there's a Standard Finish that's right for you.

If you're looking for code-approved materials for fireblocking, the International Residential Code has got you covered. The IRC provides a list of acceptable fireblocking materials that can be used in most locations.

Nominal 2-in. lumber is one of the approved materials, making it a great option for fireblocking. You can also use a double layer of nominal 1-in. lumber with offset lap joints.

Wood structural panels, such as OSB or plywood, are also approved when they're at least 23⁄32-in. thick. The joints should be over framing or backed with a piece of 23⁄32-in. panel.

Particleboard is another option, requiring a thickness of at least 3⁄4-in. with joints over framing or backed by 3⁄4-in. particleboard. Gypsum board, or drywall, is also approved at a minimum thickness of 1⁄2-in.

Cement-based millboard is approved at a minimum thickness of 1⁄4-in. Mineral wool or glass fiber batts or blankets are also acceptable, as long as they're installed in a way that keeps them securely in place.

Some materials may not be listed in the code, but can still be used with the inspector's approval. For example, fireblocking spray foam may be used around vents, pipes, wires, and cables, but only if it's installed according to the manufacturer's instructions and has been third-party tested and approved for code compliance.

Here's a list of code-approved materials for fireblocking:

When choosing the right materials for your project, EverKem fire caulking is a crucial component to consider.

Using EverKem 814+ intumescent fire caulking with Vulcan Vents is a recommended practice, as it helps ensure an air-tight seal.

Prior to installing the vent, run a bead of EverKem behind the nailing flange to seal any gaps between the vent and the building material.

This simple step ensures that no gaps are present where flying embers might enter and cause damage.

To get the most out of EverKem, follow these installation tips: