.png)
How Roofing Manufacturers Influence a Commercial Roof Specification
- 20 hours ago
- 5 min read
When planning a commercial roof refurbishment or replacement, choosing the waterproofing system is only part of the process.
Roofing manufacturers can also play an important role in how a commercial roof is specified. Different manufacturers offer different systems, components, technical support and warranty options, and the proposed specification needs to work with the existing building rather than simply selecting a familiar product.
For building owners, housing providers, managing agents and public-sector organisations, understanding the manufacturer's role can help explain why one roofing system may be recommended over another.
What Is a Commercial Roofing Specification?
A roofing specification sets out how the proposed roof should be constructed and the materials and systems required to achieve the intended performance.
Depending on the project, it may cover:
Waterproofing system
Insulation
Vapour control layers
Primers and preparation
Roof outlets and drainage
Upstands and penetrations
Rooflights
Edge details
Fire performance
Installation requirements
Manufacturer requirements
Warranty or guarantee
On a large commercial project, the specification provides a clear basis for contractors to price and install the works.
We've previously looked at how to write a commercial roofing specification that gets better quotes, including why a clear scope can make roofing tenders easier to compare.
Why Does the Roofing Manufacturer Matter?
Commercial roofing systems aren't simply individual waterproofing products.
Manufacturers often provide complete systems in which the waterproofing membrane, insulation, vapour control layer, primers and accessories are designed to work together.
Using compatible components is particularly important where a manufacturer-backed system or warranty is required.
The manufacturer selected can therefore influence the complete roof build-up rather than just the visible waterproofing layer.
Different Manufacturers Specialise in Different Roofing Systems
There isn't one manufacturer that's best for every commercial roof.
Some offer broad ranges covering several waterproofing technologies, while others specialise in particular systems or applications.
PRC works with established roofing manufacturers including Bauder, Garland, Langley, Alumasc, Soprema, Proteus, Polyroof, Nimbus, Triflex and WestWood.
The appropriate choice depends on the building, existing roof and project requirements.
Built-Up Felt Roofing Manufacturers
Built-up bituminous roofing remains widely used for commercial and public-sector refurbishment projects.
Manufacturers such as Bauder, Garland, Langley, Alumasc and Soprema offer systems that can be specified for different roof constructions and performance requirements.
These systems may incorporate waterproofing membranes, insulation, vapour control layers and associated components within a complete roof build-up.
Built-up felt can be particularly appropriate for large flat roofs, housing blocks, schools and other commercial or public-sector properties.
Liquid Waterproofing Manufacturers
Cold-applied liquid roofing can offer advantages where roofs contain complicated detailing or where reducing hot works is beneficial.
Manufacturers such as Triflex, WestWood, Proteus and Polyroof provide specialist liquid waterproofing systems suitable for a range of commercial refurbishment applications.
Liquid systems can be particularly useful around:
Plant and equipment
Rooflights
Pipework
Penetrations
Outlets
Upstands
Balconies and terraces
Complex junctions
However, the presence of complicated details doesn't automatically mean liquid waterproofing should be specified.
The existing substrate, roof condition and intended use still need to be considered.
Technical Support Can Influence the Specification
One advantage of working with established roofing manufacturers is the technical information available for their systems.
Depending on the manufacturer and project, this can help with matters such as roof build-up, detailing, insulation, compatible components and installation requirements.
For larger or more complicated projects, this can be particularly valuable because the specification can be developed around the actual roof rather than relying on a generic solution.
The level and type of technical involvement varies between manufacturers and projects, so it should be established when the specification is being developed.
The Existing Roof Still Comes First
A manufacturer shouldn't be chosen simply because its name is familiar or because its system has been used successfully on another building.
The existing roof needs to be considered first.
Factors that can influence manufacturer and system selection include:
Structural deck
Existing waterproofing
Moisture within the roof
Insulation
Roof falls
Drainage
Existing overlays
Plant and penetrations
Fire requirements
Access
Building use
A system that works extremely well on one commercial building may be inappropriate for another.
Our guide to choosing a roofing system for a commercial roof refurbishment looks at these factors and the differences between built-up felt, single-ply and liquid waterproofing in more detail.
Manufacturer Specifications Can Help Contractors Price the Same Scope
One of the challenges with commercial roofing tenders is ensuring contractors are pricing comparable works.
If one contractor allows for a different insulation thickness, waterproofing system or preparation method, quotations can vary considerably even when they appear to cover the same roof.
A clear roofing specification can reduce some of this uncertainty.
Where a particular manufacturer and system have been specified, tendering contractors can price against a more clearly defined roof build-up.
This doesn't mean every quotation will be identical. Access, preliminaries, programme, additional works and other factors can still affect price.
It's one reason roofing tenders often receive widely different prices, even where contractors are looking at the same building.
Manufacturer Warranties Can Affect System Selection
Warranty requirements can also influence which roofing system is selected.
For commercial property owners, councils and housing providers, a manufacturer-backed warranty may be an important requirement of the project.
Warranty terms and requirements vary between manufacturers and systems.
The specification and installation therefore need to meet the relevant manufacturer's requirements where a particular warranty is being provided.
This is something that should be considered early in the project rather than once the roof has already been installed.
Installation Matters as Much as the Product
Even a high-quality roofing system can perform poorly if it isn't installed correctly.
Commercial roofs contain numerous details where workmanship is particularly important, including outlets, upstands, penetrations, rooflights and changes in level.
The contractor therefore needs to understand the specified system and install it in accordance with the relevant requirements.
Where manufacturers operate approved or authorised contractor schemes for particular systems, this can also form part of the project's contractor-selection process.
PRC works with a range of manufacturers and installs systems appropriate for commercial, public-sector and multi-residential roofing projects.
Why Might a Specification Change?
The roofing system initially considered for a project isn't necessarily the one that will ultimately be installed.
Further investigation can reveal conditions that affect the specification.
For example, the existing insulation may be wet, the deck may require additional work or previously hidden layers may be discovered.
The proposed system may then need to change to reflect what has actually been found.
This isn't necessarily a problem with the original specification.
As we've previously explained, roofing specifications can change after further investigation, particularly on refurbishment projects where parts of the existing construction are concealed.
Should You Specify the Manufacturer or the Roofing System First?
Generally, the requirements of the roof should lead the decision.
The first questions should be things such as:
What is the existing roof construction?
What condition is it in?
Does it need to be stripped, overlaid or locally repaired?
What performance is required?
How is the building used?
Are there particular warranty, fire, insulation or programme requirements?
Once these requirements are understood, an appropriate roofing system and manufacturer can be considered.
Starting with a manufacturer and attempting to make its system fit every building can result in the wrong approach.
Manufacturer Choice on Public-Sector and Housing Projects
Manufacturer selection can be particularly important on public-sector and housing projects.
These roofs often form part of larger planned refurbishment programmes and may need to meet defined performance, warranty and procurement requirements.
Buildings may also remain occupied throughout the works.
Selecting an appropriate system therefore involves considering not only waterproofing but also installation methods, programme, resident or building-user disruption and long-term maintenance.
Our Stamford Hill Estate case study is an example of a large occupied residential refurbishment project where a Bauder warm-roof system was installed across six buildings.
Roofing Manufacturer Systems Installed by PRC
Premier Roofing & Construction installs commercial roofing systems from a range of established manufacturers across London, Essex, Kent and the wider South East.
Our manufacturer experience includes systems from:
Different manufacturers and systems are suited to different roof constructions and project requirements, so the objective is to select a specification appropriate for the building rather than defaulting to a single roofing product.
