Flat Roofs and Flat Roofing Systems

Flat roofing is experiencing a resurgence in popularity across the UK, due to advances in building standards and design, materials and waterproofing systems. Take a comprehensive approach to your flat roof project and we’ll help you from the very start.

PermaRoof UK offers expert advice and project-specific product guidance, whether you’re a DIYer or a homeowner looking for a professional flat roofing installer or a project manager in need of technical and specification support.

Let PermaRoof UK help you seal and protect your flat roofing for the long term with a range of systems to suit all types of project from the roof deck – up. We stock proven, branded EPDM membranes and innovative liquid roofing for a truly seamless approach to waterproofing complex flat roof designs.

Our online store is a one-stop-shop for domestic flat roofing and offers secure ordering, same day order turnaround and fast UK-wide delivery:

• RubberCover EPDM
• Fleeceback EPDM roofing
• P100 Liquid roofing
• Skylights and trim
• Cover board and insulation

A flat roof is not technically flat at all. It is instead typically installed with a slight minimum fall of 1:40 to facilitate efficient rainwater runoff. The gradient can be created during the deck construction or with the use of tapered insulation boards beneath the waterproofing layer.

Flat roofing suffered a period of decline from the 1980s, due to poor performance which led to leaks, damp and other issues. In recent years, construction methods and materials have improved considerably in the domestic sector and flat roof projects are again on the rise.

To avoid returning to the issues of a failed flat roof consider the benefits of a modern approach before turning to your usual solution. The poor reputation of flat roofing was largely the fault of the waterproofing materials and this is where costly mistakes can be made.

A flat roof is more vulnerable to water ponding and ingress through the smallest of faults and this is why the waterproofing must be seamlessly reliable. The type of waterproofing system you choose will depend on many factors – and as flat roofing systems specialists, we’re here to guide you through. With expert advice, high performance systems, free install guides and exceptional customer support for DIY, you can rely on us.

Flat roofing projects require careful planning and we’re here to help. Our award-winning sales and customer support teams provide project-specific expert advice, product guidance and installation support, whether you’re doing it yourself or looking for a reliable contractor. When you’re scoping out the project and thinking about materials, considerations need to made right from the start:

Local Authority Permission

While permission is not always needed to replace existing systems, building compliance is mandatory in the UK, so an awareness of current standards is crucial, whether you’re making seemingly significant changes or not. For a new build, such as a flat roof extension or garden room, planning permission will almost certainly be needed. This can sometimes be true for change of use too – a garage to a spare bedroom, for instance.

In some cases and regions, your choice of materials could contribute to the likelihood of planning permission being granted without amendments or conditions in a new build. Local authority rules and criteria will differ, so a visit to the local planning department can be a wise move for homeowners. It can highlight both constraints and incentives in the use of certain materials, particularly insulation or eco roofing systems.

Structural Integrity

The condition and integrity of the roof deck should be considered when planning to replace existing waterproofing on a flat roof. If the deck is damaged, perhaps from a previous leak, then the damaged areas should be repaired or replaced to avoid problems later. High performance systems like EPDM have an exceptional service life expectancy of over 50 years and require full contact adhesion for the best results.

It should be remembered that green and other eco roofing systems require additional load bearing capacity due to the combined weight of insulating and often gravel-based drainage layers above the membrane and beneath the planting medium. If you are unsure whether your flat roof is in good condition or capable of bearing additional weight, call in a building inspector, surveyor or professional roofer to help.

Roof Build Up

For a full flat roof build-up, consideration needs to be made for insulation and ventilation. There are many types of insulation with varying thermal properties to suit the building needs and energy requirements. Ensure that there is adequate airflow to prevent condensation from forming, as this can lead to issues with mould or damp later.

Some types of roofing design allow for insulation on the inside of the roof deck, while others may be installed above the roof deck and under the waterproofing system.

Location and Weather

In the UK, homeowners do consider the weather when planning major projects. This is both in terms of materials and products selection and installation. As we experience frequent rain, it is important to make sure that the flat roof is designed to handle water runoff adequately, materials are seamlessly reliable and that gutters and drains can flow freely.

EPDM waterproofing systems typically have dedicated accessories fitted to drain outlets and trim systems are designed to direct water to the gutter edge.

Cost vs. Value

When working on budgeting, consider the long-term value of a high performance flat roofing system. EPDM has a life expectancy of 50 years and while potentially requiring a higher initial investment than felt, for instance, is likely to last three or more times longer.

Modern liquid roofing systems also come with a long life expectancy and offer seamless coverage, making them a cost-efficient solution for more complex flat roofing projects over the long term.

When you weigh up the cost of replacing felt repeatedly and maintaining and repairing it in between, the gap between value and cost is very different.

The importance of accurate measurements

Most flat roofing systems are quantified and sold in meterage – linear and square metres (for coverage). It cannot be stressed how important it is to measure accurately. Measure the long and short sides using a long tape where possible to avoid miscalculations. Double check measurements and have a second person present or to check the measurements separately.

Once you have accurate measurements in metres and have made the square meterage calculation, you can use these to order the correct materials quantities or input them into our flat roof kit builder tool.

Homeowners planning projects with new flat roofing will likely engage a professional building company to handle the construction side of things. Flat roofs are not entirely flat and require careful construction to ensure rainwater falls away and doesn’t pool anywhere, so it is wise to go with a professional for this part of the build.

However, installing the waterproofing is well within the means of a competent DIYer with good levels of confidence and skill. Systems like RubberCover provide a simplified approach to installation, with one-piece membranes, cold, water-based adhesives and install accessories, making them ideal for DIY.

Our extensive resource library has been developed to cover preparation and all the major aspects of install from main area application to accessories and upstands. We’re here to support you every step of the way if you decide to handle the waterproofing yourself.

If you decide DIY isn’t for you, a professional EPDM installer will be able to complete your installation easily and quickly – it may not cost as much as you think…

EPDM is the perfect system for DIY installers, fast and easy to fit in a single sheet for most domestic flat roofing projects. There are specific stages in the process of installation and we’re here to guide you through. We have an extensive library of installation guides, videos and online tutorials – browse them all below.

Preparation

Some preparation of the flat roof deck is required before you begin installing any new covering. The deck needs to be clean, oil, grease and preferably dust-free. Any existing roof covering should be fully removed for the best results and for full adhesion of EPDM rubber membranes.

If you’re installing insulation or recovery boards beneath the membrane, you need not worry too much about removing the old covering fully but ensure that there is no debris left on the roof deck that may cause damage.

Check the materials

Making sure you have everything you need is essential. Double check all the components are there and lay out the membrane to rest over the flat roof for at least half an hour to allow packaging creases to dissipate. Occasionally, particularly if membrane or kits have been stored for a while, there may be stubborn creases that require a little help. We provide full instructions for this in our video library.

Installation process

Note that flat roof decks that are not of timber construction will typically require the use of primer and contact bonding adhesive. Water-based adhesives are used for timber decks only. Liquid systems provide a good alternative option for sealing a concrete roof.

Position the membrane so that it is roughly in position with an even overhang where appropriate. Working in sections is a good idea on both large and smaller projects. When fitting a shed roof kit, for instance, fold the membrane back over itself and work on one side of the shed roof, before repeating on the other side.

Spray adhesive is applied to both the back of the membrane and to the roof deck. This must then be allowed to ‘go-off’ for a few minutes until it becomes tacky to the touch. Roll the membrane over the tacky roof deck and smooth with an EPDM roller or soft to medium bristled household broom to remove any trapped air.

Around the edges of the system, a roofing trim may be used to trap the EPDM and create a watertight seal. Trim can complete an installation and is recommended for both aesthetics and performance on flat roof projects. Full installation guidelines are available in the resource library below.

The PermaRoof Resource library is packed with free information to help guide our trade and DIY customers through your flat roofing projects. The video library contains step-by-step tutorials in all aspects of installation or download installation guides, technical and product information, safety data and much more in PDF format. If you can’t find what you’re looking for, give us a call and we’ll be glad to help.

It’s now time to get your flat roofing project underway. We stock everything you need in our online store and offer fast, UK wide delivery to help keep your  project on track. We work with some of the biggest names in the construction industry, providing genuine, high performance branded systems, complete with technical certifications and manufacturer warranties.

The award-winning teams are on hand if you need assistance with your order, so please get in touch if we can help – try the PermaRoof UK way.