Roof and Wall System

New MatriX System – River-Therm®

River-Therm® is a built-up site assembled secret fix roof system that is used worldwide and is available in the UK and Ireland from CA Building Products.

River-Therm® can be roll formed on site to remove the need for end laps on long slopes and the unique geometric locking action means that the system is simply installed by foot pressure. The fully walkable roofing solution is best known for its incorporated drainage channel which in 2009 enabled CA Building Products to manufacture and install almost 1,000 roof sheets each 180 metres in length Prologis and Marks & Spencer at their Bradford Distribution Centre.

The entire system, and not only its constituent parts, has been independently verified by Agrément certification and the Loss Prevention Certification Board (LPCB).

No Leaks

River-Therm®'s Unique Drainage Chanel
River-Therm®’s Unique Drainage Channel

The drainage channel is one of the key features of River-Therm®. All standing seam and secret fix roofs are designed to breathe through the side lap, this is fundamental to the overall success of the system.  However, where air can flow, so can water. In a storm, water can be slowed or stopped as it runs off the roof. With nowhere to go the water rises and the profile is quickly submerged. The unique River-Therm® drainage channel captures any water and directs it towards the gutter and away from the building, eliminating the risk of leaks.

River-Therm® can be rolled on site with no end laps, reducing the need for expensive ridge details and internal gutters which are potential hotspots for water ingress. Inplane and barrel vault rooflight options are available with the River-Therm® system. The roof covering can provide natural daylight even at very low pitches. With approved details for sealing penetrations in both steel and aluminium the River-Therm® system provides a complete engineered solution to protect against the UK’s inclement weather.

Pitched Roofs

River-Therm® Pitched Roof

The principle functions of profiled roofing and cladding are to create a weather tight envelope which keeps the heat in and to brace the frame.

In order to make a building weather-tight, the precise pitch at the end laps must be considered. Since the introduction of steel profiled sheeting as a roof waterproof layer, the industry has limited end laps to a minimum of 4° after deflection, however, in recent years profile manufacturers have developed roof systems which take into account all components used in the tested assembly and in some cases it is possible to design a roof with a pitch lower than the historical recommendation.

All CA Building Products roof systems have been designed and tested to be installed at roof pitches lower than this generic recommendation. For further information on the design parameters of the systems offered please refer to the Technical Information Papers, available in the technical section of the website.

Curved Roofs

Prologis / Marks & Spencer, Bradford

With greater demands being placed on maximum usable space and in cases where overall building height is an issue for planning purposes, the River-Therm® secret-fix roofing system is the logical option.

Suitable for use on a wide range of building applications, the system allows clients and architects a multitude of design possibilities. Low pitch and/or large radius roofs are possible with single length panels, either factory or site rolled, to suit the projects requirements. River-Therm® can be used on roofs with pitches of 1° after steelwork deflection at panel ends.

Whether manufactured from steel or aluminium the River-Therm® external profile has exceptional self-curving capabilities with a convex design radius as low as 30 metres. Where tighter radii are required the profile can be mechanically curved to a smooth finish of 6 metres in length. With the non-fragile, fully walkable liner panel providing a minimum self curve radius of 45 metres and crimp curving capabilities as good as the external sheet, the system is a logical solution to meet many project requirements.

Non-Fragility & Walkablility

Long River-Therm® sheet instaltion
Long River-Therm® sheet instaltion

The River-Therm® system has been designed to be both non-fragile and fully walkable for both the liner and external profile.

As a minimum the system is supplied with a CA 32 1000RL 0.7mm thick (nominal) steel liner panel, which provides safety while moving long length panels around the roof and minimises the risk of damage during construction.

The system, as well as liner as a standalone element, has been tested for non-fragility in accordance with ACR[M]001:2011 ‘Test for Non-Fragility of Profiled Sheeted and Large Element Roofing Assemblies (Fourth Edition)’ achieving a Class B certification for the complete assembly.

Walkability tests carried out under laboratory conditions involved the continual application and release of pressure onto the River-Therm® profile to simulate constant and increasing foot traffic via a rubber clad piston. The test pressures were steadily increased until the sheet failed by creasing and side lap failure. The test results surpassed all expectations, achieving excellent point load capability.

Health and Safety

Fully walkable systems

With many roofing products and components weighing well in excess of 20kg/m² the architect and building owner both have a responsibility when managing the risks of manual handling. The River-Therm® system is simple to install, with no heavy individual components, eliminating risks of manual handling, both on the ground and at height.

All of the roof system assemblies delivered by CA Building Products have been tested for non-fragility in accordance with ACR[M]001:2011 ‘Test for Non-Fragility of Profiled Sheeted and Large Element Roofing Assemblies (Fourth Edition)’ achieving Class B certification.

Today, many Horizontal Life Line (HLL) system manufacturers and installers are suggesting that their systems are ‘approved’ or ‘fit for purpose’ in conjunction with CA Building Products’ roof cladding systems, this can only be claimed if the systems, in their entirety, have been subject to the relevant tests.  For further information refer to, ‘ACR[CP]007: – The use of Horizontal Safety Lines in Roofwork’.

CA Building Products have worked closely with a select few HLL manufacturers to ensure that the safety systems they produce meet the required standards of CA Group’s 25-year guarantee. Contact CA Group Technical Department for a current up to date list of recommended partners.

Thermal Performance

Royal Mail Northampton

The Matrix Spacer System used in all CA Building Products roof and wall cladding systems allows for deeper insulation and flexibility in design, with achievable U-values a low as 0.14W/m²K with no additional components. All the systems offered are site assembled and as such allow for specialist components to be added, i.e. acoustic insulations.

All our systems have been comprehensively tested to prove their structural performance at Lucideon.

The spacing of the brackets used on the Matrix Spacer System allows the insulation to be installed below the bar without the need for cutting and tucking. U-values and system build-up information is available from the technical section of the website.

Based on current building regulations to meet the minimum backstop U-values, the build-up depth for the River-Therm® system is as follows:

River-Therm® roof CA 32 1000RL – 0.24W/m²K – 195mm cavity + 43mm external profile = 238mm

Good detailing – robust detailing as it is known – can offer serious reductions in lost heat and therefore cost from buildings.

Previous tests have proven that one of the primary causes of heat loss from buildings is due to poor detailing. Poor detailing allows heat to travel from the inside of a building to the outside often via poorly designed flashings, gutters, junctions and interfaces. To put this into context, some details, like drip flashings, which run around the entire perimeter of the building at the base of the walls can, if they are not designed and installed with care, act as huge heat conductors, drawing heat from the warm interior and allowing it to be wasted by passing to the exterior of the building envelope.

By insisting on robust detailing the ‘heat sink’ effect of detailing which allows a direct connection between the inside (the warm side) and the outside (the cold side) of a building can be minimised and in some cases, completely eradicated.

A thermal performance increase of 7.5% can be achieved at no additional cost just by introducing robust detailing to every junction throughout the building envelope. Good detailing like this makes the difference between a good Energy Performance Certificate rating and a poor one.

CA Group Technical Department have compiled an extensive library of ‘robust’ details all of which are offered as standard details at no extra cost, these are available from the technical download section.

Material Choices

River-Therm® MaterialsRiver-Therm® offers developers, specifiers and architects a cost effective secret fix roofing solution with a high degree of flexibility enabling the building designer to choose a material that caters for their architectural need. As standard the system is available in Colorcoat HPS200 Ultra® and Colorcoat Prisma® steel or mill finish, stucco embossed and PVDF coated aluminium. As well as the standard material options the system can also be supplied in stainless steel, copper and zinc.

Positive Programme Impact

Programme is critical. Reducing the site programme saves money. The ability to line the building out using lightweight materials eliminates manual handling risks, as well as creating a weather and air-tight platform that allows the main contractor to begin their internal work such as laying the floor slab at the earliest opportunity. Installed by simple foot pressure, River-Therm® offers accelerated installation without compromise and requires no specialist machinery unlike other secret-fix and standing seam solutions. The system is supported by a comprehensive training regime from the CA Group Technical Department, which offers in-house training, on-site inductions and detailed design for installers.

Rolling Options

The River-Therm® secret-fix roofing solution can be produced to the same high standards whether it is rolled under factory conditions or on site at the project location. River-Therm® is manufactured on a fully engineered, factory specification production unit regardless of the location.

One of the most critical aspects of material production whether in the factory or on site is speed. The River-Therm® rolling mill has been specifically designed to offer clients, developers, specifiers and contractors a number of options for delivering an installed solution as efficiently as possible.

Eaves Level Rolling

Rolling At Eaves

Rolling at eaves level using the River-Therm® factory specification mobile roll forming mill, does not compromise the speed or quality of River-Therm®. Any sheet length is available, with limitations being set only by the length of the coil. This method reduces the risk of damage by minimising the number of handling processes.

Ramp Rolling

Ramp Rolling

Ramp rolling is primarily used when crane usage is restricted, preventing eaves level rolling from taking place. Ramps, which are widely available for hire across the UK, can be situated onsite for long periods of time at a relatively low cost providing there is space available.

Ground Level Rolling

Ground rolling

Where projects are too long for factory rolling or if the size of the project would require numerous deliveries to site, increasing transport costs and associated CO2 emissions, ground level rolling on site may be a better option. The River-Therm® mobile roll forming mill arrives on site ready to roll straight from the back of the trailer.

Factory Rolled Panels

Panels can also be manufactured at our factory in Evenwood, County Durham and delivered to site for immediate loading onto the roof or storing at ground level. This method has little impact on site other than the space for transport and offloading equipment and is the preferred option for smaller projects.

Air Permeability

Waitrose - Chorley with an air permeability rating of 0.98m³/hr/m² @ 50Pa
Waitrose – Chorley with an air permeability rating of 0.99m³/hr/m² @ 50Pa

Air permeability, has been widely identified as the primary source of heat loss from a building’s interior. Reducing air permeability is a major factor in demonstrating compliance with Building Regulations and where heating is required can make the difference between a pass and a fail. A good air permeability result will aid in delivering EPC ratings in Band A, providing high asset values and strong yields.

Heat loss not only contributes to higher building running costs but also increases unnecessary CO2 emissions, due to the additional heating load required to replace it. The critical element to achieve good air tightness is the flexibility of the cladding system in accommodating variances in steelwork tolerances. Inadequately designed or poorly installed steelwork can deflect under its own weight or under the weight of the gutters and the cladding system connected to it.

Built up metal cladding systems accommodate this degree of flexibility, the metal liners used follow the variations in steelwork making it easier for the cladding contractor to effect a seal. With the fixings and sealing methods adopted on the River-Therm® system achieving results as low as 0.99m³/hr/m² @ 50Pa.


Mega PhoneCA Building Products roof and wall cladding systems have been tested at a number of independent test houses throughout the UK, such as Sound Research Laboratories (SRL) in Suffolk. The tests have included determination of weighted sound reduction and rain noise levels for our standard systems as well as the absorption coefficients when incorporating perforated lining panels.

In addition, CA Group can produce project specific predictions for standard multilayer constructions and where necessary the more complicated build-ups can be outsourced to recognised independent specialists familiar with these types of cladding system.

Based on standard U-values the River-Therm® system achieves the following weighted sound reduction figures without any enhancements;

River-Therm® roof 0.7mm liner – 45dB

For further information on the system capabilities download the relevant Technical Information Paper on Acoustics.


Drops - Condensation

The installed liner panel provides an extremely efficient air barrier, with the lowest known air permeability test of 0.99m³/hr/m² @ 50Pa achieved; this greatly reduces the transfer of heat from inside the building to outside. To further support the durability of the system the Therma-quilt insulation has every fibre coated with silicone to ensure that any moisture in the cavity is not absorbed and is shed to the liner where it is either dissipated or directed away from the building via the gutter.

With over 1 million m² of built-up roof and wall systems from CA Building Products installed every year there are very few reported issues of the cladding itself causing problems. Coating the fibres with silicone negates the need for a separate breather paper, except in humidity Class 5 applications i.e. swimming pools. For further information on this subject download the relevant Technical Information Paper.


Thurrock distribution centre fire
Thurrock distribution centre fire

Many cladding systems sold in the UK claim that they can protect a building from fire, but the majority of buildings are far from safe. River-Therm® on the other hand, is made from logically non-combustible materials.

River-Therm® has been tested by BRE Loss Prevention Certification Board to LPS 1181 Part 1 achieving ‘EXT-B’ classification as standard. The insulation used in the system is also tested to BS 476 and is classified as non-combustible in its own right, delivering confidence to all and in particular to the tenant that in the event of a fire the insulation in their roof and walls will not contribute to the fire load. Many clients also insist, as well as the roof and wall insulations that the internal gutters are also insulated with Manmade Mineral Fibre (MMMF) to eliminate this critical risk.

CA Building Products also offers dedicated FireWall solutions, the Twin-Therm® FW15 and FW30, which provide 240 minutes structural integrity & 15 minutes insulation (LPS1181 ‘EXT-A15’) / 30 minutes insulation (LPS1181 ‘EXT-A30’) respectively.


System Guarantees without the hassle

We know that when choosing a cladding system, confidence in its lifespan is a major factor. Unlike most suppliers of twin skin cladding, CA Building Products offer full system guarantees for up to 25 years on River-Therm®.

The guarantee covers the manufacture and design of the whole system including all of the components supplied by CA Building Products such as, screws, sealants, insulation, spacers, etc. This delivery is offered alongside the Confidex® Guarantee when specified using Colorcoat HPS200 Ultra® and / or Colorcoat Prisma® offering peace of mind for up to 40 years. For further information on this subject download the relevant Technical Information Paper.

If we are to offer meaningful system guarantees of up to 25 years the systems have to be meaningful in their durability. River-Therm® is supported by a number of reputable, recognised third party organisations such as the BRE (LPCB) and Exova Warringtonfire. Many people have Agrément certification for individual components but River-Therm® is supported by a Agrément certification for the entire system.

Fibre Insulation

Fibre Insulation
Foam Free – CFC, HCFC & VOC Free

A  UNEP report ‘HFCs: A Critical Link in Protecting Climate and the Ozone Layer’*, highlights the potential dangers associated with use of hydrofluorocarbons (HFC’s) as replacements in insulation using chlorofluorocarbons (CFC’s) and hydrochlorofluorocarbons (HCFC’s).

The Therma-quilt insulation supplied as part of the River-Therm® roof and wall cladding system is a non-hygroscopic glasswool with individual fibres which are coated with silicone to prevent moisture retention and maintain the thermal efficiency of the system. Therma-quilt is CE Marked, complies with the Lambda 90/90 as well as achieving zero Ozone Depleting Potential (ODP) and zero Global Warming Potential (GWP).

Therma-quilt is produced from fine, non-combustible glass mineral wool (as defined in BS 3533: 1981), bonded with a thermo-setting resin. Therma-quilt is made from natural materials and recycled glass and is free from CFC, HCFC Volatile Organic Compounds (VOC’s). Therma-quilt it does not rot, degrade or sustain vermin and will not encourage the growth of mould, bacteria or fungi.

Therma-quilt insulation has also been assessed by the LPCB and classified “non-combustible” in its own right.

Cite ‘UNEP 2011 HFCs: A Critical Link in Protecting Climate and the Ozone Layer. United Nations Environment Programme (UNEP), 36pp’

Responsible Sourcing

CA Group, takes responsibility for the environment seriously without gimmicks or tokenism.

All materials within the River-Therm® system are fully recyclable to enable a low ‘cradle to cradle’ carbon footprint, with a net commercial benefit on scrap values at end of life. The Therma-quilt non-combustible insulation is supplied with zero Global Warming Potential and zero Ozone Depletion Potential that never utilises CFC’s, HCFC’s or VOC’s in the production process. The system has a minimal environmental impact when transported to site, due the amount of profiled material which can be transported in each load, a factor which also helps to reduce fuel costs.


Transportation has to consider not only delivery requirements at the beginning of a project but also at disposal.

It is at this stage as legislation has toughened that building running costs are recognised as punitive. The majority of systems supplied by CA Group are either reused i.e. farm buildings etc or sent back to the steel mill for recycling, the residue (insulation and fixings) can either be reused as cavity wall insulation or sent to landfill at minimal cost.

CA Group understand the implications of the entire process from ‘cradle to cradle’ through production of Environmental Product Declarations.


Steelwork Aerial

Most roofing and cladding contractors have encountered steelwork tolerance issues when installing both pitched and curved roofs. Care must be taken to minimise deflection on purlins. In some instances, particularly with facetted rafters, purlin cleats can be as deep 500mm. Even a small misalignment can have a significant effect on the position of the top flange of the purlin to which the roof cladding is fixed. To ensure this does not occur, the steelwork contractor must be aware of the system requirements.  To facilitate this process we always recommend collaboration between the client, architect, main contractor, steelwork contractor and system supplier to ensure the project is delivered without any problems.

All built up metal roofing assemblies require a positive fall from apex to gutter, whether on a pitched or curved roof, the simplest way is for the steelwork contractor to ensure a purlin is located close to the apex, as with all traditional portal frame designs.


Site safety is paramount.  Any worker accessing the roof during maintenance inspections and working procedures must be subject to the proper training.  We also recommend that adequate and appropriate safe access should be provided at all times.  Full risk assessments and method statements should be carried out for each individual project.

Safety precautions must be taken for the whole duration of inspections and works. HSG 33 ‘Health & Safety in Roofwork’, available from the HSE, provides detailed advice in this subject.

For further information on this matter refer to the Technical Information Paper on ‘Walkable, Non-Walkable & Walking on Roof Cladding’.


25,000m2 of Twin-Therm® Roof on 6 trailers
25,000m2 of Twin-Therm® Roof on 6 trailers

Over recent years CA Building Products has focused on the reduction of CO2 emissions resulting from the transportation of materials to site. With up to 35 vehicles per day delivering throughout the country, the associated CO2 emissions were high, as were the transport costs.  Following a total review, together with our customers, a number of new procedures have been implemented.

For example, prior to the review, on a typical 10,000m2 retail store, a complete order would be shipped on up to 17 vehicles.  Today this has been reduced to 11 vehicles, which is a 35% reduction in CO2. By reducing our CO2 emissions we were also able to cut our costs, a saving which was passed on to our customers.

CA Building Products endorses the concept of ‘cradle-to-cradle’ construction, which requires that building materials used in the conception of a building also take into account its end-of-life impact by being ecologically compatible, economically acceptable and socially responsible in equal measure.


Daylight - Rooflights B&Q Preston

The controlled addition of natural light, either direct or diffuse, into a building will reduce the use of electric lighting and ultimately lower the buildings running costs.

The inclusion of natural daylighting also plays a significant role in compliance with Building Regulations ADL2.  However,  in terms of meeting compliance it is not just the thermal performance of the roof lights that must be considered, further information in regards to roof light area, light transmission and solar gain is required to ensure that the inclusion of natural daylighting does not generate excessive heat inside the building.

With U-values of 1.3W/m²K available as standard and the ability to offer alternatives down to 0.8W/m²K, the Therma-light system from CA Building Products can be easily integrated into any of its built-up roof cladding systems.

When specifying roof lights it is important to ensure that the entire roof covering still retains its performance criteria, especially in relation to non-fragility, system life and required guarantee periods.  All roof cladding systems from CA Building Products are designed for the inclusion of the Therma-light GRP rooflight system.

River-Therm® Downloads & Information

Wednesday, July 25th, 2012