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Professional Guide

Best Intumescent Strips for Fire Safety: 2025 Expert Review

DJ

DR Joinery

Expert Joiner & Fire Door Specialist

Published 12 December 2025

Ensuring your property is compliant with fire safety regulations is one of the most serious responsibilities a homeowner or landlord has. Whether you are managing a Victorian conversion in York or a modern office, the humble intumescent strip is your first line of defence against the spread of smoke and fire.

I often see fire doors fitted poorly, with strips that have either peeled off due to cheap adhesive or were never the right specification in the first place. There is a big difference between 'rebated' strips (which sit flush inside the door or frame) and 'surface-mounted' options for retrofitting.

In this review, I've selected three products that cater to different needs: a budget-friendly rebated option for new installs, a premium surface-mounted kit, and a reliable solution from a trusted trade brand for tricky retrofits.

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Specs vs. The Real World

The Spec: "Self-Adhesive Installation"

The Theory

"Anyone can stick these on in seconds for instant protection."

The Reality

If the frame is dusty, greasy, or painted with gloss that hasn't cured, the adhesive will fail within weeks. Surface preparation is absolutely vital.

The Spec: "Smoke & Fire Protection"

The Theory

"Installing strips ensures 30 minutes of fire resistance."

The Reality

The strips only work if the door gap is correct (3mm-4mm). If the gap is too wide (over 4mm), the intumescent material may not expand enough to bridge it. If it's too tight, the door won't close properly, rendering it useless.

My Top 3 Recommendations

Three options to cover different needs and budgets

EAI Fire & Smoke Seal Intumescent Door Strips - 5 Pack

Budget Pick
EAI Fire & Smoke Seal Intumescent Door Strips - 5 Pack

EAI

This is a classic 'rebated' seal, meaning it is designed to sit inside a groove routed into the door or frame. At roughly £4 per metre, it offers excellent value for joiners or competent DIYers who have the tools to cut a 10mm channel. It provides a flush, professional finish that doesn't interfere with the door face.

Price£20.95 (at time of writing)
TypeRebated (Requires routing)
Dimensions105cm x 10mm x 4mm
RatingFD30 (30 minutes)
The Good
  • Professional flush finish (hidden when door is closed)
  • Includes brush pile for smoke protection
  • Cost-effective for multi-door projects
The Bad
  • Requires a router and jig to install (not for novices)
  • Short 105cm lengths mean you will have joints in the vertical stiles
  • Colour matching limited to white

Installer Tip:

Because these come in 105cm lengths, you'll need to join them. Always cut the join at a 45-degree angle rather than a straight butt joint; this helps keep the brush pile continuous and prevents the seal from snagging.

Priced at £20.95 at the time of writing

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EAI Surface Self Adhesive Intumescent Seal Strip - 5.2m Kit

Quality Pick
EAI Surface Self Adhesive Intumescent Seal Strip - 5.2m Kit

EAI

This is a surface-mounted solution, ideal for upgrading existing doors without mess or machinery. It distinguishes itself as a 'quality' option because it comes as a complete compliance kit, including the essential 'Fire Door Keep Shut' signs. The 5.2m roll is sufficient for one standard door frame with no waste.

Price£28.90 (at time of writing)
TypeSurface Mounted
Length5.2m (Enough for one door)
RatingBS 476 Part 22
The Good
  • No routing required - sticks to the frame surface
  • Continuous roll eliminates unsightly joins
  • Includes mandatory fire door signage
The Bad
  • More expensive per door than rebated options
  • Visible on the frame rebate (not flush)
  • Can reduce the door gap significantly

Installer Tip:

Before you stick this on, check your door gaps. This strip is 1.8mm thick. If your door is already tight (less than 3mm gap), adding this will stop the door from closing or latching. You might need to plane the door edge slightly first.

Priced at £28.90 at the time of writing

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Exitex Self Adhesive Intumescent Fire Door Strip - 5.2m

Problem-Solving
Exitex Self Adhesive Intumescent Fire Door Strip - 5.2m

Exitex

Exitex is a brand plenty of us in the trade recognise and trust. This product is the problem-solver for older properties where routing out a groove isn't an option due to the frame condition. The inclusion of an alcohol wipe might seem minor, but it effectively solves the #1 cause of failure: poor adhesion.

Price£24.99 (at time of writing)
TypeSurface Mounted / Retrofit
BrandExitex (Trusted Trade Brand)
ExtrasAlcohol preparation wipe included
The Good
  • Trusted trade brand (Exitex) known for durability
  • Includes surface preparation wipe to ensure bond
  • Ideal for retrofitting older doors in conservation areas
The Bad
  • Surface mounting is less tamper-proof than rebated
  • Brush pile height (5mm) requires a decent gap

Installer Tip:

Surface-mounted strips are great, but they are vulnerable to being picked at. Place the strip on the frame rebate (the stop) rather than the door edge if possible. This keeps it slightly more protected from traffic and tampering.

Priced at £24.99 at the time of writing

Check Price on Amazon

Frequently Asked Questions

What is the difference between intumescent strips and smoke seals?
An intumescent strip is the chemical part that expands under high heat to seal the door against fire. A smoke seal is usually a nylon brush or rubber fin attached to the strip that stops cold smoke from passing through before the heat rises. For full compliance, we almost always recommend combined fire and smoke seals.
Can I fit intumescent strips myself?
Surface-mounted strips are DIY-friendly provided you prepare the surface properly. However, rebated strips require a router and precise woodworking skills. If you are a landlord in York, remember that incorrect installation could void your fire safety compliance, so professional installation is often safer.
Do I need to replace the whole door to fit these?
Not necessarily. If your existing door is a rated fire door (look for a label or plug on the top edge) but lacks seals, you can retrofit surface-mounted strips like the Exitex or EAI options reviewed here. However, if the door itself isn't fire-rated, adding strips won't make it one.
Rebated vs Surface Mounted: Which is better?
Rebated (cut-in) seals are superior for longevity and aesthetics; they can't be peeled off easily and look professional. Surface-mounted seals are a problem-solver for existing doors where you cannot remove the door or cut into the frame, but they can affect how the door closes and are more prone to damage.
Why do the strips have brushes?
The brush is for smoke control. In the early stages of a fire, smoke is the biggest killer, not the flames. The brush blocks the gap around the door to prevent smoke from filling the escape route, whilst the intumescent strip behind it waits for the heat to trigger expansion.
How do I check if my fire door gaps are correct?
You need a gap of roughly 3mm to 4mm between the door and the frame for the strips to work effectively. If the gap is less than 3mm, the intumescent material might not have space to expand, or the brush will bind. If it's over 4mm, the seal might not bridge the gap fully. A £1 coin is roughly 2.3mm thick—so a gap just larger than a pound coin is a good rule of thumb.

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