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GRP Barrel Vaults for Industrial Roofs

Homebase Exterior, Multivault Rooflights

Factory assembled GRP vault rooflights lap together to form rooflights of unlimited length with spanning capabilities up to 4 metres. Multivault GRP are delivered to site in a factory assembled ready to install form. Multivault GRP is ideal for all roof types and are fitted onto separate kerbs, without any fixings penetrating the roof covering to preserve the principle of secret fix. The integrated aluminium bar and the well fitting insulated aluminium end closures makes Multivault GRP a robust rooflight option.

Multivault GRP Features and Options


Glazing Double and Triple Skin
Tints* Translucent
Curve radius (mm) 3150
Span Width (mm) Up to 4000
Module Length (mm) 255 / 1020
Weight - outer (kg/m2) 2.2
Service Temperature  
Range (ºC) -20 to +80
Light Transmission  
(Double skin - clear %) 58
U value (W/m2K)  
Double skin 2.2
Triple skin 1.3

Smoothly curving factory assembled GRP vault rooflights lap together to form rooflights of unlimited length with spanning capabilities up to 4 metres. Integrated aluminium bar and insulated aluminium end closures create a strong rooflight.


Light Levels 

The provision of natural daylight is a regulatory requirement, with recommendations for a minimum rooflight area of 10%, a 12% area for industrial buildings, and a greater percentage of rooflights for buildings such as sports halls etc.


Vault rooflights are compatible with most commonly used building materials. However, solvents and alkaline cleaners should not be used with any vault rooflight. Polycarbonate vault rooflights should not come into contact with any plastisol coated steel.


Appropriate roof apertures and insulated kerbs in either timber, steel, GRP or concrete for the fitting of the selected vault rooflight system must be provided by the contractor.


Vault rooflights should always be handled by two people. If vaults are to be mechanically handled they must be secured on pallets and deposited at safe positions on the roof. Great care must be taken with all vaults in windy conditions.


All vault rooflights should be stored in cool, dry conditions away from direct sunlight, preferably indoors. If outside storage is unavoidable the units should be stacked on a pallet and covered with an opaque waterproof cover draped over timbers placed on the top vault to ventilate the stack and prevent overheating.


Rooflight installations must comply with the Construction (Design and Management) Regulations 1994. Vault installations in all materials can be made to satisfy the Regulations. Brett Martin CDM specifications and guidance should be obtained for specific projects.

Brett Martin recommend that rooflights should not be walked on under any circumstances.

Maintenance and Cleaning

The general condition of units and all accessories, particularly security of fixings and sealants, should be checked periodically. Abrasive and alkali cleaning materials should be avoided. A mild detergent and a soft rag or sponge can be used to remove surface dirt.

Technical Support

Please contact Brett Martin for further guidance, including technical bulletins on installation, handling and maintenance, COSHH data sheets, NBS product specification clauses and CPD seminars.


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