Top 6 most common commercial weatherproofing mistakes

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Getting roof weatherproofing right is essential for any building – it protects the building envelope from damage caused by damp, rainwater ingress and wind, and it also protects the contents of the building and the building occupants. 

Over the years, we’ve been called out to repair hundreds of commercial roofs, and there are several weatherproofing mistakes we often see – many of which could have been easily avoided with careful planning, expert knowledge, and a skilled hand. 

Here are the six most common commercial weatherproofing mistakes we’ve seen, along with advice on how to prevent problems, mitigate damage and ensure proper repairs are carried out.

1. Neglecting maintenance

The amount of maintenance required for a commercial roof will depend on how the roof is constructed and what kind of weatherproofing is used. 

Many commercial roofs are flat roofs covered with bitumen, EPDM, metal, or thermoplastics, and these require regular maintenance and inspections to check for buckling, cracking, pooling, shrinking, damage, or deterioration. Any issues will need to be addressed quickly, as it doesn’t take long for a small problem to grow into a much larger one.

However, GRP (glass reinforced plastic) roofs, also known as fibreglass roofs, require almost no maintenance. Regular cleaning is all they need to retain their appearance and durability. GRP roofs have an expected lifespan of at least 25 years, and many last much longer than that. Of course, no roofing system is entirely problem-free, so even GRP roofs should be checked regularly to ensure they’re in good condition.

2. Not investigating underlying problems

When you notice a crack in the roof covering, discover a leak or spot a bit of pooling water on a flat roof, your first instinct may be to quickly patch up the problem and assume it’s taken care of. 

However, many roof weatherproofing issues are symptoms of underlying problems. For example, pooling water could indicate a poorly designed roof, weak or damaged roof structure or, in the case of roofs covered with a hot bituminous system, improper mopping that created voids in the membrane. 

If these underlying issues aren’t recognised – usually with the help of a commercial roofing expert – and properly dealt with, the problem is likely to return and increase in severity.

3. Blocked drainage or inadequate drainage

Standing water is a significant problem for commercial flat roofs for several reasons. For one thing, it adds weight, which could cause sagging and deterioration of the roof surface. For another, standing water is more likely to find its way through imperfections in the roof surface. It also encourages the growth of plants and moss. 

Keeping drains, gutters, and downpipes clear is part of good roof maintenance and will help ensure water leaves the rooftop quickly and efficiently. However, other drainage problems, such as a poorly designed roof or not enough drainage, will require the knowledge and skills of an expert roofing contractor to put things right.

4. Poorly constructed roof penetrations

Commercial buildings are likely to have a variety of roof penetrations, ranging from rooflights, access hatches and lift shafts to openings for HVAC equipment, chimneys, manufacturing plant and other machinery. If these penetrations aren’t carefully planned, constructed, and weatherproofed, there will likely be problems with leaks and drainage.

Ideally, roof penetrations should be considered early in the building design process. Working with a commercial roof expert will help to ensure that the penetration is constructed and weatherproofed adequately. 

However, roof penetrations are often installed after roof construction is complete – sometimes years later when the building is undergoing a change of use or refurbishment. In these cases, a roof penetrations expert can provide advice and guidance on the best locations for penetrations, the types of support required and how to weatherproof the installation for long-term reliability. 

And if an existing roof penetration is suffering wind damage or rainwater ingress, an expert can provide advice and carry out remedial works to resolve the problem.

roof penetration installers tall pipes on top of a roof

5. Improper repairs

We often see cases where previous repairs were carried out using the wrong materials or installation methods. Sometimes this simply means that the repairs didn’t work or only lasted a short time. However, a bad repair job can cause more roof damage.

For example, it’s not unusual to see metal roofs that have been patched up with caulking and plastic roof cement. These materials are not fit for purpose and are likely to fail, especially in extreme weather conditions. On single-ply membrane roofs, roof cement can damage the roofing surface, as the solvents in the cement may dissolve plastics like PVC and EPDM.

The lesson here is that if commercial roof repairs are needed, it may be tempting to DIY it or find the cheapest rate around. But it usually pays to have a knowledgeable professional survey the damage and carry out repairs that will remain structurally sound and weathertight for years to come.

6. Not enlisting the help of a commercial roof weatherproofing expert

As we’ve already mentioned, calling in an expert with specific knowledge of commercial roof weatherproofing is the best course of action for building, repairing, or renovating a commercial roof.

Jones and Woolman UK has extensive experience in commercial roof weatherproofing, and we have worked on a wide range of projects, from shopping centres, schools and factories to data centres, airports, and sports arenas. Our cold-applied liquid fibreglass roofs provide a robust, reliable, and weathertight surface, and the system also works with all kinds of roof penetrations to provide a weatherproof seal.

We recommend getting in touch from the very earliest stages of a project. That way, we can provide advice and liaise with other teams to ensure the best results using the most straightforward methods. However, our flexible system, combined with our ability to design and build bespoke GRP components, enables us to successfully deliver reliable weatherproofing, backed by our 25-year guarantee, no matter how far along the project may be.

Get in touch to find out more about commercial roof weatherproofing, or discuss your next project with a weatherproofing expert, you can also call on 01922 712111.

The need to review weatherproofing methods for modular building application

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The focus on efficient modular buildings is growing, highlighting the need for a review of weatherproofing methods and materials. The popularity of modular buildings is partially caused by the increasing pressure to deliver buildings faster and more cost-effectively. Fast-changing regulations that mandate significant improvements to the building performance are also a factor. The Department for Education (DfE) modular framework agreement announced at the beginning of 2020, with an investment of £3 billion, indicates a wider government shift toward modern methods of construction (MMC). This means that other traditional construction methods, such as weatherproofing, will need to be reviewed to ensure they are compatible with the modular approach and reflect the same values.

What are the benefits of modular construction and what are the challenges to wider uptake?

The need for more schools, hospitals, and other commercial buildings in the UK, whilst ensuring their impact on the environment and its resources is reduced, requires a shift within the construction industry to deliver an increased number of commercial spaces using fewer resources. Compliance with regulatory standards and the quality of these structures is also crucial to ensure performance, longevity, and an environment pleasant for building users. Modular building’s streamlined design, manufacture, and installation processes, using Modern Methods of Construction (MMC), makes them well placed to ensure the UK’s needs can be quickly and efficiently met.

MMC aims to streamline the most skill and labour-intensive stages of manufacture and installation and is key to the success of modular buildings within the commercial sector. Moving as many construction processes as possible into a controlled manufacturing environment has the potential to improve efficiency and protect resources, however, challenges with compliance and a lack of understanding of application has meant uptake was initially slow. Growing financial support from both UK Government and private investors, changes to legislation, and increasing needs for commercial structures is now opening doors to an increased use of modular buildings.

The impact of weatherproofing on the building performance

High performance weatherproofing is vital to the function of any building type and to maximise its lifecycle. Many traditional weatherproofing methods that worked well in conventional construction, however, do not necessarily fit modular assembly and may not align directly with the modular value of efficiency. Demands on labour and materials, lack of speed and flexibility and the resources and processes established weatherproofing use, are some of the issues causing this disconnect.

Improved planning and improvements to traditional weatherproofing application methods, or systems, may alleviate some of the issues. In the long run, improvements to existing methods are not sufficient. Weatherproofing systems will need to be evaluated in terms of the whole design, manufacture, and assembly of the building. A purpose designed weatherproofing solution can therefore provide the right platform to streamline the construction of modular buildings in the future.

Jones and Woolman UK have over 40-years of experience in the design, manufacture and installation of weatherproofing solutions on some of the most challenging and exciting projects in the UK and abroad. The experience and reputation as industry innovators has placed Jones and Woolman UK well to work with developers and contractors to improve the delivery of weatherproofing for modular buildings. This innovation started within the initial planning process. Incorporation of weatherproofing into the initial design of modular buildings allowed for better allocation of on and off-site application of weatherproofing. This meant the final stage of projects, usually the most resource intensive, is handled more time and cost effectively and the finished weatherproofing is of the highest quality.

To find out more about the benefits of modular construction and the considerations for weatherproofing of modular building construction, download our whitepaper ‘Streamlining weatherproofing in modular construction’. For advice on building penetrations and weatherproofing systems and how these can be designed for your next project, contact our team of technical experts.

Why is weatherproofing of modular buildings important?

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The increase in specification of modular buildings is driven by the construction efficiency and quality it promises. Effective weatherproofing is a crucial steppingstone to achieving the efficiencies modular buildings set out to deliver.

The need for additional housing, schools, hospitals, and improved infrastructure is increasing across the UK. This need has resulted in pressure to speed up project delivery and reduce the cost of construction to cope with demand. This is intensifying project scheduling and straining the supply chain whilst performance targets for buildings are becoming more stringent.

The impending changes to Part L and Part F, as part of the Future Homes Standard, reflect Government plans to improve the energy efficiency of buildings to reduce primary energy demands and lower carbon emissions, with the overall aim to decarbonise the grid by 2050. Effective weatherproofing has a huge role to play, as it is a prerequisite for a well-performing building envelope.

Modular buildings and a net-zero future

There is an obvious need to increase the energy efficiency of our buildings to combat climate change and deliver zero carbon buildings of the future. The focus of the construction industry is shifting towards the use of more sustainable methods and materials in order to reduce the carbon footprint further. New UK legislation also sets compliance targets for the design of healthy buildings. Provisions for sufficient fresh air and daylight [EN17037] for the occupants are especially important for both wellbeing and performance of occupants. In the ever-changing landscape of construction, the industry now finds itself in a position where traditional construction methods simply cannot deliver projects matching all performance markers.

The call to revolutionise the ‘underachieving’ construction industry was at the heart of the Egan report, summarised as: “..the Task Force wishes to emphasise that we are not inviting UK construction to look at what it does already and do it better: we are asking the industry and Government to join with major clients to do it entirely differently” [Rethinking Construction, 1998].

The notion of revolutionising construction is at the heart of the Construction 2025 document produced by the Government in collaboration with industry. The report sets out a vision for the future of UK construction:

  1. A 33% reduction in both the initial cost of construction and the whole-life cost of assets
  2. A 50% reduction in the overall time from inception to completion for new build and refurbished assets
  3. A 50% reduction in greenhouse gas emissions in the built environment
  4. A 50% reduction in the trade gap between total exports and total imports for construction products and materials

A failure to follow through with these changes would further jeopardise our path to a low-carbon future.

What steps have been taken so far?

The modular approach to construction is not a completely new approach. We have seen previous attempts in the 1950s through to the 1970s, but a lack of supply chain stability and the perceived temporary nature and reduced life expectancy meant uptake was slow. More recently, we saw a more widespread deployment of BIM modelling to streamline design and provide a blueprint for a more efficient construction phase. Although improvements have been made, these are incremental and do not satisfy the objectives of the report. A completely new approach was required and contractors and clients in the UK are now getting to grips with MMC with a focus on off-site fabrication and modular methodologies.

Jones and Woolman UK have been at the forefront of innovation for over 40-years and are well positioned to take on the challenges of MMC. Our recent involvement in large modular projects across a variety of sectors has demonstrated that early involvement of a weatherproofing expert is crucial to realising the benefits of modular methodology for any project.

Our whitepaper ‘Streamlining weatherproofing in modular construction’ focuses closely on the role of modular buildings and how effective weatherproofing is helping to improve the efficiency of our buildings to deliver net-zero carbon by 2050. If you would like to find out how effective and flexible weatherproofing can help improve the energy efficiency of your project without impact on your scheduling, contact one of our industry experts.

What are the four challenges for the weatherproofing of modular buildings?

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The challenges construction (and weatherproofing) face in order to achieve 2050 net-zero targets are considerable. It is no longer enough to do things better; the industry needs to look at innovating and doing things altogether differently. The ‘Construction 2025 Document’ outlines the joint strategy from both government and industry for the future of UK construction through four pillars:

  • 33% reduction in both the initial cost of construction and the whole life cost of assets
  • 50% reduction in the overall time from inception to completion for new build and refurbished assets
  • 50% reduction in green gas emissions in the built environment
  • 50% reduction in the trade gap between total exports and total imports for construction materials

Modular construction offers solutions that can help achieve the targets across all pillars.

Cost of construction

Prefabrication of the most resource intensive areas of construction allows for better use of materials and better allocation of resources, and as a result is more cost-effective than traditional on-site construction.

A high level of prefabrication means that the end-to-end quality is guaranteed, mitigating risks and reducing defects in buildings. As a result, building efficiency is greatly improved providing long term savings by reducing energy demand and the need for frequent maintenance.

The implications for the lifecycle cost of the building lie in the flexibility of the modules that can be exchanged. This could be used to upgrade a plant room that is coming to end-of-life but also to change the design of the building if required. Operational maintenance and repurposing of buildings become considerably more cost-effective.

Speed of delivery

Modularisation leads to standardisation of processes which in turn lead to improved efficiency and productivity on site. As we know, the construction phase can be subject to lengthy delays caused by unpredictable events that impact the delivery schedule of projects. A high level of prefabrication shortens the less predictable construction phase and as a result, more development can be delivered on schedule.

Energy efficiency & sustainability

The increased focus on carbon reductions and primary energy targets are driving factors in modern construction. Volumetric modular buildings are designed and constructed to higher sustainability standards and are capable of far superior energy performance if the building envelope is weathertight and thermally efficient.

Use of modern materials, reduced site traffic, less waste and the possibility of building recycling reduce the embodied carbon of construction. The Current Practices and Future Potential in Modern Methods of Construction quote that overall, when comparing the energy used to construct a building, modular methods can deliver the same building using 67% less energy than the traditional method.

Import and export trade gap reduction

In the current context of Brexit, which is still causing some uncertainty, and the impact of the Covid-19 crisis across industries, it is difficult to project where the priorities will lie in the months ahead. For off-site construction to be efficient, a large-scale operation is required, and this is only possible with the support of UK government. There is a need to unite the sector, upskill the workforce and strengthen the supply chain. Department Government infrastructure strategies are expected to focus on construction with a promised increase in spending to £5.6bn. A large part of this strategy is faster project delivery, led by the newly created ‘Project Speed’. The Department for Education announced an investment of £3bn in off-site school procurement in England aiming to deliver over 30 schools in the next four years. Modular construction will undoubtedly play a central part in the UK economy.

Modular construction holds answers to many of the challenges that the construction industry faces. Weatherproofing modules off-site and on-site is one of those challenges that need to be overcome to ensure modular benefits, such as increased thermal efficiencies, are retained. Jones and Woolman UK have been involved in numerous modular projects and through 40-years of innovation are able to work with their partners to devise weatherproofing systems and streamline construction strategies. Materials, techniques and completed systems have been vigorously tested across various climates and applications to deliver a long-lasting, thermally efficient building envelope for modular buildings.

To read more on the considerations for weatherproofing of modular buildings and their benefits, download our whitepaper ‘Streamlining weatherproofing in modular construction’. Contact our team of experts for help with specification and design or any other advice on building penetrations and weatherproofing systems.

What are the 5 considerations for weatherproofing modular buildings?

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There are five considerations for weatherproofing of modular buildings:

  • Integration of mechanical, electrical and plumbing services (MEP) and daylight openings
  • Sequencing and scheduling
  • Energy strategy of the development
  • Flexibility of the modular building
  • Quality & aesthetics

Well designed and installed weatherproofing is integral to the protection of building fabric but also plays an important part in supporting the thermal performance of buildings. It is crucial to consider the weatherproofing of a modular building at an early stage of the design.

Integration of mechanical, electrical and plumbing services (MEP) and daylight openings

The architecture of modern buildings has been moving towards human-centred design with optimal daylight levels and increased ventilation. EN 17037 was recently introduced to set the minimum performance target in this area. The specification of roof glazing has also been increasing rapidly as the lack of ground space and financial constraints compel building design vertically.

Modern buildings also require a large number of services to support their functions. The increasing popularity of alternative energy sources, such as PV panels, and low carbon technologies, such as heat pumps, is increasing.

The consequence of this growing number of building services and daylight openings is more specialist roof installations with electrical and mechanical components together with both horizontal and vertical building penetrations. These require careful consideration at the design stage to prevent scheduling, installation and quality issues that can be costly to put right later.

The best approach would be to find a specialist services/rooflight installer who could not only install the required upstands, but also fit the services or rooflights and weatherproof the entire solution in one pass. Not only would this streamline the entire process, but it would also ensure that there are no sequencing issues with the individual stages and any impact from weather conditions is kept to the absolute minimum.

Sequencing and scheduling

Regardless of whether a modular project is managed in-house or through a variety of manufacturers and contractors, early engagement with a weatherproofing expert is key. Each of the project management scenarios will result in variations to the sequencing of works. The move of a large proportion of the on-site works into a factory environment significantly shortens the construction period.

The smallest errors, such as not taking into account transportation height before installing roof windows onto modules in a factory, may have a vast impact on the efficiency of the construction and the speed of project delivery. The risks of lead-time changes for products, or disadvantageous weather, need to be taken into consideration when specifying a weatherproofing system to avoid delays that may cause water ingress and damage to the modules.

Energy strategy of the development

Use of new materials and better build quality of prefabricated modules can help deliver buildings with significantly improved thermal performance. To be energy efficient, the building envelope must deliver in terms of air and water tightness, insulation and condensation control. Poor weatherproofing can result in unsatisfactory building performance and negatively impact the long-term running costs through increased maintenance and energy demand.

The flexibility of a modular building

Modular buildings can be utilised as both temporary and permanent structures. The capacity of temporary modular buildings to be moved to a different location or dismantled and recycled when no longer required is a huge financial and environmental benefit. The choice of weatherproofing should reflect the flexibility of modular buildings to ensure it can be easily removed without causing damage to the modules.

Quality & Aesthetics

Choice of weatherproofing detail should support the building design. Modular buildings can have a large number of matelines and the majority of services are on the roof. Whilst matelines can be used as a design feature, service and daylight penetrations generally require a seamless, colour matched finish. Weatherproofing should retain its colour and remain stain-free and robust, whilst blending into its surroundings for an aesthetically pleasing finish. Insufficient or badly designed weatherproofing, delays in the application, or an inferior weatherproofing quality, could lead to damage to the building fabric, or to any pre-installed services and furnishings of the modules.

For the best possible performance within modular construction, a homogenous integration of the weatherproofing with the building needs to be targeted. Jones & Woolman UK have long been proponents of considering weatherproofing at the design stage. With 40-years of experience in the industry, we are best placed to address the issues encountered with weatherproofing of modular building. Jones and Woolman UK work with the largest modular manufacturers and UK building contractors to deliver innovative weatherproofing across all sectors.

Jones & Woolman UK also pride themself on being able to offer a one-stop-shop approach regarding rooflight installations and other types of services. Experts in upstand installation, rooflight fitting and weatherproofing, the team at Jones & Woolman UK can help any project save time and money on these types of installations by offering the whole package, again backed by their industry leading warranty.

To find out more about the considerations for weatherproofing of modular buildings, download our whitepaper ‘Streamlining weatherproofing in modular construction’. If you need help or advice with a weatherproofing system for your new project or would like design advice, contact our team of technical experts.

How to deal with building envelope penetrations of modular structures

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To successfully deal with building envelope penetrations for modular buildings, we must overcome a different set of challenges that traditional construction presents us with. Naturally, every project brings different obstacles but there are three challenges all modular projects have in common when it comes to building penetrations:

  • Lack of standardisation
  • Transport limitations
  • Off-site or on-site installation

Regardless of the construction method, building penetrations and their weatherproofing must be designed to form holistic systems within the building. McKinsey & Company quote in their Modular Construction: From projects to products that modular construction can cut the schedule by 20-50%. The design, planning and sequencing for any building penetrations work, installation of various elements and subsequent weatherproofing must be addressed in the initial stages of the project design to deliver a shorter construction phase.

Lack of standardisation

Lack of standardisation within the modular sector means that the design and planning of building penetrations must be managed effectively to adjust for variations between manufacturers of the modular units and variations throughout the supply chain. Early planning and sequencing should address supply chain variations. Appropriate coordination will allow for many MEP (mechanical, electrical, and plumbing) and daylight elements to be fully installed and weatherproofed off-site, avoiding the need for any adjustments in-situ or reactive specification changes.

Transport limitations

Off-site manufactured modules, including any additional installations, need to be transported to site. Transport restrictions may pose a challenge. Where full pre-installation and building penetration weatherproofing cannot be completed off-site, a partial preinstallation may still be advantageous and should be pursued. As with the lack of standardisation, preinstallation will streamline remaining in-situ works, allowing kerbs, upstands, or plant risers to be designed and prefabricated to synchronise lead and installation times with the glazing or MEP manufacturers and installers.

Off-site or on-site installation?

Despite planning and pre-installation being viable options, some weatherproofing installations cannot be completed in a controlled off-site environment. In some instances, an on-site installation is simply preferred because of project specific needs. Weather changes, on-site accidents and scheduling clashes, among other unpredictable events, can impact the certainty of delivery that modular projects heavily depend on.

Weatherproofing is a part of the construction process that is weather dependent and requires ongoing coordination with other trades on site. Unexpected issues can often call for late changes to penetration positioning. The weatherproofing solution specified, and its installers, should be flexible and the application process robust enough to accommodate these events and to do so without an effect on the project timeline.

The innovation of technologies and materials forming weathering systems can help reduce some of the mentioned risks. Jones and Woolman UK have over 40-years of experience and a reputation for continual improvements to the materials, adhesives and flexible mouldings used on projects of all sizes and types. The weatherproofing systems made by Jones and Woolman UK undergo strenuous independent testing for integrity in extreme temperatures and after accelerated ageing. The long-standing cooperation with contractors and manufacturers put Jones and Woolman UK in a position to work within the modular industry and find innovative solutions based on the specific challenges of modular delivery.

You can read more on how to deal with building envelope penetrations and weatherproofing systems for modular buildings in our whitepaper ‘Streamlining weatherproofing in modular construction’. Contact our team of technical experts if you require help with design, specification or any other advice on building penetrations and weatherproofing systems.