Home > Companies > Siderise Group > SIDERISE Mullion and Transom Inserts for Curtain Walling (formerly Lamaphon Mullion / Transom Inserts)

SIDERISE Mullion and Transom Inserts comprise a range of specialist material components intended to improve the sound insulation performance of lightweight hollow framed façades or glazed areas. Whilst the inserts may be employed for the purpose of improving the sound transmission characteristics of the building envelope (e.g. outside to inside performance), more commonly they are used to assist in reducing flanking transmission between adjacent internal areas. This includes ‘room to room’ and ‘floor to floor’ flanking sound transmission. Specific optimal solutions have been developed for each of the common conditions encountered in curtain wall constructions. The design of the appropriate insert considers not only acoustic performance but also ease and practicality of installation. In-house manufacturing techniques such as CNC/ die cutting or routing permits an accurate tailored fit within the particular hollow frame element.

SIDERISE AVC Mullion Closures:

A dense resilient foam material with a central flexible heavy membrane. Usually die-cut to the exact internal profile of the hollow frame section. Depending on the sound insulation performance required they may be deployed singly or in pairs.


Comprises a layer of V Foam with a 10 kg/m² limp elastomeric barrier membrane to one side. Theproduct is fitted in pairs in a back-to-back arrangement with the barrier layers to the outside.


Resin bonded rock fibre absorptive insert.

SIDERISE V Foam Baffles:

Impregnated acoustic foam absorptive insert, typically in 300–600 mm lengths and are usually installed centred on the midpoint of the compartment line.

SIDERISE V Foam Inserts:

Impregnated acoustic foam absorptive insert. Robust, flexible and dust free.


  • Excellent acoustic performance.
  • Custom dimensions and shapes.
  • Simple to install.
  • Wide range of base materials.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-80-40/400 Sound attenuators

NBS Specification

NBS Buliding logo
This product is associated with the following NBS clauses:

Product specification

An important note about specifying



Siderise Group


+44 (0)1656 730833

Product reference

[AVC Mullion Closures]
'Along' frame section treatment.
[HB Inserts]
'Through' frame section treatment.
[MF Inserts]
'Through' frame section treatment.
[V Foam Baffles]
'Along' frame section treatment.
[V Foam Inserts]
'Through' frame section treatment.

Manufacturer details

Forge Industrial Estate,
Mid Glamorgan, CF34 0AY
Tel +44 (0)1656 730833
Fax +44 (0)1656 812509
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