Siderise TW-P Firestop for Profiled Decks

Bespoke fire stopping solutions to seal the gaps under profiled metal decks or cladding

Created to match your project’s profile  

TW-P Firestops are blocks of fire-resistant stone wool insulation that are precisely shaped and sized to completely seal the gaps caused by profiled metal decking, coffered soffits and cladding sheets, preventing the spread of fire and smoke between compartments. TW-PP is basic firestopping, which must be installed with Siderise fire & acoustic gap sealant. TW-PS has been developed using our Lamella insulation with a robust aluminium foil facing, creating an integral smoke barrier.  

Suitable for most profile types

We have worked closely with profile deck manufacturers to build an extensive database of profile types— making specification and ordering simple


All TW-P Firestops achieve an A1 rating when tested to EN 13501-1

Wide range of fire resistance

TW-P Firestops are available with a range of fire resistance options tested to BS 476-20. TW-PP Firestops includes both EI 60 and 120 options, whilst the foil-faced TW-PS Firestops includes EI 60, 120 and 300 options

Provides acoustic benefits

TW-P Firestops can help limit sound transmission between internal spaces

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Siderise TW fire stops for profiled decks comprise of a range of fire stopping solutions designed to seal the junction between the tops of compartment walls and the underside of profiled decking.

These bespoke products are made up of materials that are supplied in various configurations to cost-effectively suit the project requirement. In every case, the materials are tailor-made to suit the shape and performance specification of the individual application.

Product Description

Siderise TW-PP fire stops are factory produced trapezoidal blocks which are shaped to close tolerances directly from a base mineral wool slab. The product provides a simple fire-rated seal to close cavities at the top of compartment walls in conjunction with profiled metal decking, coffered soffits and roofing etc. They are suitable for installation in any nominated cavity of fixed dimensions. 

Siderise TW-PP is available in set widths corresponding to the required fire rating. The major and minor dimensions are matched to the quoted internal dimensions of the profile. 

The material is cut to be nominally oversized in depth relative to the depth of the profile so as to ensure a tight compressive fit within the void.  

Should a smoke seal be required then the TW-PP must be coated with Siderise fire & acoustic gap sealant (or Siderise  TW-PS should be used). 

The Siderise  TW Fillet Blocks comprise of small section rectangular blocks of semi-rigid mineral fibre for a compressed installation within quoted metal decks. 

They are typically used to complement trapezoidal blocks as a double layer method of fire stopping holorib or dovetail deck profiles. 

The trapezoidal Siderise  TW-PP blocks are available to suit all metal decks and profiled cladding. Through a close working relationship with profile deck manufacturers, Siderise has built up an extensive database of profile types, facilitating specification and ordering. The profile reference or name of the deck can therefore be supplied at the point of enquiry to ensure the best solution for the project is selected. 

A Class A1 rated foil-faced version of the product is also available, referred to as Siderise TW-PS. This product comprises a specifically manufactured low resin content mineral fibre insulation core which is pre-compressed internally and shaped to close dimensions. The material is held in a robust lamella form by the application of reinforced foil to the exposed surfaces to give a Class A1 product. 

Please contact our technical team on for specific advice on product selection for your specific project requirements.

Fire Performance

The design and manufacture of Siderise TW is based on proven fire performance to BS 476: Part 20: 1987. 

Siderise TW-PP includes both 1 and 2 hours fire resistance in accordance with both insulation and integrity criteria. 

Siderise TW-PS includes fire resistance from 1 to 5 hours in accordance with both insulation and integrity criteria. 

The fire resistance in Tables 1 and 2 applies to the sealing of gaps over walls constructed of lightweight aggregate concrete, dense aggregate concrete, concrete blocks or clay bricks which have a minimum density of 400kg/m

Verification of fire performance is available upon request.  

Non-standard widths are also available subject to enquiry on a project basis. Contact our technical team on for advice.

Siderise TW-P Firestops for profiled decks

Table 1 - Fire performance (TW-PP System)

Product Ref Thickness (mm) Integrity (Mins) Insulation (mins)

Table 2 - Fire performance(TW-PS System)

Product Ref Thickness (mm) Integrity (Mins) Insulation (mins)
Technical Specification

Siderise TW-PP fire stops for profiled decks

Properties Value
Form Supplied Low resin mineral fibre 50mm up to 120mm thick
Colour Self coloured buff
Finish / Metal Plain
To Suit Profiles All
Density Raw material 75 kg/m3
Thermal Conductivity λ = 0.04 W/m.K
Acoustic Performance Up to 44dB (Contact our Interiors technical team with project specific details for advice).
Reaction to fire property Classified A1 to EN 13501-1
Resistance to Fire Property 60 & 120 minutes (In accordance with BS 476); Please see Table 1

Siderise TW-PS fire stops for profiled decks with aluminium foil facing

Properties Value
Form Supplied Mineral fibre foil faced both sides 50mm up to 120mm thick
Colour Silver
Finish / Metal Aluminium Foil
To Suit Profiles All
Density Nominal 75 kg/m3
Thermal Conductivity λ = 0.038 W/m.K (tested foil to foil)
Acoustic Performance Up to 51dB (Contact our Interiors technical team with project specific details for advice.)
Reaction to fire property Classified A1 to EN 13501-1
Resistance to Fire Property 30 to 300 minutes (In accordance with BS 476); Please see Table 2

The stonewool core is recyclable.

Additional Information Available

The following information is available upon request or via download from the website: 

  • NBS Specification Clause 
  • Material Safety Data Sheet 
  • Cutting and Installation instructions
Technical Support

For Technical advice or support please contact: 

For Installation Training or Site Inspections please contact:


The information in this datasheet is believed to be accurate at the date of publication. Siderise has a policy of continuous product improvement and reserves the right to alter or amend the specifications of products without prior notice. Siderise does not accept responsibility for the consequences of using the products described outside of the recommendations within this datasheet. Expert advice should be sought where there is any doubt about the correct specification or installation of Siderise products.


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Siderise Fire And Acoustic Gap Sealant


Get quick answers to common queries or contact our team for more advice. Your questions answered.

Is TW-P Firestop supplied pre-cut?

Yes, we create the fire stop to meet your exact profile shape and width requirements

What is the difference between TW-PP and TW-PS Firestops?

TW-PP is a simple stone wool block that must be installed with a specialist sealant. TW-PS features our Lamella insulation and is sealed with a robust aluminium foil facing, offering greater fire and smoke resistance where required

What is Lamella?

Siderise created Lamella insulation in the 1990s to provide a fire resistant core that could also withstand building movement for reliable form and fit. Learn more about Lamella technology

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