What is fire block insulation?

Author: Ora Ortiz  |  Last update: Wednesday, March 18, 2026

Common materials used for fire blocking include wood, drywall, particleboard, millboard, wool blankets, and glass fibre. Insulating walls with cellulose adds to protection against fire. Attaching material between wall frames and the foundation helps fill gaps.

What is the difference between fireblock and regular foam?

The main difference is that a fire-block foam has had a service evaluation to qualify it for “fire-blocking” in residential type-V (combustible) construction, typically limited to sealing around vents, pipes, ducts, and wires that run through top plates within a dwelling.

Where do you use fire block sealant?

3M™ Fire Block Sealant FB 136 will bond to most construction surfaces: concrete, brick, gypsum, metals, wood, plastic, cable jacketing and glass. No mixing required. through penetrations in wood or steel framed non-rated construction. Product may also be used around chimney, fireplace and other framing gaps.

Do all walls need fireblocking?

1. Fireblocking is required at ceiling and floor levels, and between the top story and the roof space (provided by the wall plates in platform framing). 2. Walls furred off the foundation require fireblocking every 10 ft.

When to use fire block?

states that fire blocking is required “at open- ings around vents, pipes, ducts, cables, and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion.” This means you have to seal around all those wires, pipes, and ducts that run through top plates and ...

Fireblocking and Draft Stopping

When did fireblocking become code?

In the 1990s, terminology in building codes changed, and what was previously called “fire-stopping” became “fireblocking.” This is the term still used today in section 302.11 of the IRC. The term “firestopping” is still used in the IRC (section R302.

Where is fireblocking foam required?

Yes “fireblocking” is required in COMBUSTIBLE construction. It's required: 1) at 10' intervals (both vertically and horizontally) in concealed spaces, 2) between floor lines, and 3) between top flood and attics. (See ICC 718.2.)

Is fire caulk the same as regular caulk?

In summary, firestop caulk provides fire-resistant capabilities, while regular caulking prevents water damage and improves building aesthetics. Is caulk fire-resistant? No, not all caulks are fire-resistant. Most caulks are primarily designed to seal gaps, joints, and openings.

What can be used for fireblocking?

1) 2x nominal lumber 2) ¾” plywood or OSB 3) ½” Drywall or better 4) Mineral wool or Fiberglass batt “securely retained in place” in an approved manner Fiberglass batt used as fireblock must entirely fill the cavity protected and must be packed tightly around any obstruction such as a duct or pipe. R302.

Can I use fiberglass insulation for fire blocking?

Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be allowed as fireblocking in walls constructed using parallel rows of studs or staggered studs.

What is the difference between draftstopping and fireblocking?

You'll notice that acceptable fireblocking materials tend to be rather substantial since they're intended to inhibit the passage of fire. As we'll see in a moment, draftstopping materials are lighter materials because they're intended to reduce the passage of smoke and gases.

How long does fireblock foam take to cure?

Dries tack-free in approximately 5 minutes. Foam is cuttable in about 1 hour. Full cure occurs within 24 hours.

Does fire caulk have to be red?

The building codes do not mandate any specific color for firestopping products and speak only in regard to the relevant test standards necessary to demonstrate firestops meet appropriate performance requirements and where firestop installations are necessary within a building.

Can spray foam be used as a fire barrier?

This issue is addressed in a report from the National Association of State Fire Marshals. However, just because spray foam manufacturers add fire retardant, it doesn't automatically mean that the product is fire resistant. Fire code requires a 5 or 15 minutes intumescent coating to be painted over the foam.

Do you have to be certified to install fire caulking?

You would need to check the building specifications for the certification requirements of a person installing firestop. There may be no requirement, or they may specify that you need to be certified through a firestop manufacturer, FM, or UL certification programs.

Can you use epoxy instead of caulk?

One that changes the way you do things and what you think is possible from the moment you start using it. Sentura is a 2-part flexible epoxy/resin used to fill voids. Sentura repairs cracked grout, eliminates caulk, repairs cracked tiles, fills holes in natural stone and much more.

Do you have to fire caulk both sides of a wall?

Generally, firestop solutions are tested installed from both sides of the wall though. It is often assumed that the plasterboard provides the fire resistance, when in fact it is the wall as a system – that means the stud and the board on both sides of the wall – that provides the overall fire rating.

Can I use foam as fire blocking?

Loctite Fire Block Foam is a specially designed insulating foam to fill gaps and resist the migration of fire and hot gasses in Type V residential (wood frame) construction. This foam is orange in color and is easily identifiable on the jobsite.

What is the maximum gap for fire foam?

A: Fire Door Foam has been fire tested to 60 minutes (BS476 Pt20/22: 1987 & BS EN1634-1) in timber and composite doorsets and timber glazed screens. Q: What is the minimum and maximum gaps Fire Door Foam™ can be used? A: The minimum practical width is 5mm and maximum tested gap is 33mm.

Do interior walls need fire blocking?

Practicing safe habits and removing flammable material is one thing, but you may be surprised how gaps/holes in the wall and ceiling allow fires to spread throughout a structure. In addition, the added airflow they have can feed into a fire. Fire blocking for interior walls is essential to help here.

What are four locations that require firestopping?

Firestopping is required at the following locations:
  • Pipe penetrations.
  • Joints.
  • Top of walls.
  • Curtain walls.
  • Slab edges.

What material is used for fireblock?

Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place shall be permitted as an acceptable fire block.

Previous article
Is quarter round supposed to match floor or baseboard?
Next article
Is it better to reline or replace pipes?