Blue Roofing

Blue roofing is rising in popularity, helping to minimise surface water runoff impact across the country’s urban zones. Whether you’re planning a blue system or creating a combined blue and green roofing project, talk to us and let us help.

We’re committed to making the UK greener, one roof at a time. We can help you with high performance waterproofing to form the perfect base layer for a blue roof and much more. Talk to our team about environmentally friendlier roofing systems today.

Blue roofing is not a new concept, having existed in some form for around seventy years. However, today some of the latest technologies are being used in these environmentally friendlier solutions and this is contributing to its rise in popularity. The blue roof system has developed in recent years primarily to assist urban surface water management and reduce local flooding.

The aim of this system is to collect and temporarily retain or store rainwater, which is later released at a controlled, pre-determined rate into local surface water drains. Some blue roofs include a water filtration system to minimise the risk of polluted water entering public waterways. Blue roofing systems are most commonly installed on flat roofs above a reliable waterproofing membrane. Water catchment, storage and controlled release options are numerous, giving installers greater scope for design.

In addition to surface water management, some types of blue roofing can be used for domestic rainwater harvesting. This water can then be reused, reducing the reliance on mains water supply for gardening, flushing toilets or cleaning, for instance. This would be subject to local planning guidelines, as some geographic locations may have restrictions on harvesting in place.

For the additional weight and load requirements, typical of blue roofing, an inverted roof design is ideal. This is because it allows for movement and protects the underlying membrane – it is a variant of the ballasted roof system. Here we demonstrate using a concrete based flat roof as an example. The blue roof water catchment system would be installed above these base layers:

1. Ballast layer – in a brown roof design, this would consist of the biodiverse top layer, stones or other selected ballast
2. Geotextile protection matting
3. Insulating layer to achieve thermal performance requirements
4. Waterproofing membrane installed over the vapour barrier/deck
5. A vapour control barrier may be required to protect the membrane
6. The surface of the concrete should be primed before application of the vapour control layer (if required)
7. The concrete deck should achieve a required minimum slope to facilitate efficient drainage – ideally this will not exceed 10%.

Arguably, the waterproofing in blue roofing projects is one of the most important parts to get right. Blue roofs are designed to capture and hold water, before releasing it gradually. Any volume of water poses a leak risk and the waterproofing needs to be seamlessly dependable if this water won’t immediately drain away.

Because the blue roof system is installed over the waterproofing membrane, a high performance, long lasting approach is advisable. Replacing membrane at a later date is not an option once the blue roof is in and doing its job. Getting this part of the project wrong could prove to be a costly mistake in the long run.

There are three types of reliable waterproofing that we would choose for blue roofs:

EPDM membrane – EPDM is the ideal choice for delivering a highly reliable waterproofing base for blue roofing. Once the system is fully installed, membrane failure could prove catastrophic to the entire project. EPDM can bring a range of benefits:

• Service life expectancy of more than 50 years
• Typically laid in a single sheet with no joins
• Faster to install due to the size of sheets available – up to 15.24m x 60m
• Remains durable and flexible throughout the exceptional lifespan
• High UV resistance and ozone stability

Fleece backed EPDM has a high puncture resistance and as such, has been commonly used in green roofing systems across the UK. Both types of membrane will require some form of protection to avoid being damaged by the rest of the system installed above.

Liquid PU waterproofing – also acceptably known as liquid rubber, this type of waterproofing can provide an exceptionally reliable solution. It is perfect for complex roofing designs where membrane is difficult to install. Find out more about PermaRoof’s liquid waterproofing solution here.

The success of any roofing installation, and particularly complex green and blue roofs, lies in the planning and design of the system. With so many options available, but many location and situation-dependent, make sure you choose a reputable professional to talk you through them.

Here are a few considerations to add to your planning list:

Planning permission and building regs – British Standards and guidelines apply to several aspects of a blue roof project, from collection and discharge to outlets and accessibility. Contact the local planning department to find out more about the permissions and guidelines for a blue roof.

Structural checks – it is important to conduct a structural check on the property before you choose your system and plan the installation. This is because it will carry much more weight than a conventional project. For instance, think about it in a similar way to a green roof and consider the drainage, the system itself and the additional weight of the water that will be stored there.

Call in an architect, surveyor or reliable roofing company to carry out the necessary integrity and load-bearing checks needed and make any alterations as necessary before installing the waterproofing membrane or blue roof system.

The fall of the existing roof will also be important to the design of the blue system, as water runoff happens in controlled circumstances. Alterations may need to be made in certain situations, including zero fall or those with a sharp fall to the gutter edge.

Water harvesting management – Blue roofs can potentially provide water that can be reused within the home and garden, for flushing toilets, for instance or irrigating a green roof. it is important to bear in mind though, that some regional authorities have restrictions and limits for water harvesting, so it is wise to add this to your list of planning considerations.

Growing in popularity is the process of combining blue systems with green roofing. With a strong environmental approach, this type of roofing is playing an increasingly important role in creating sustainable urban areas.

Also known as a ‘blue green roof,’ this type of system uses the conventional drainage layer of a green roof, which is often gravel or stones. As blue roofing aims to increase the volume of stored water, in addition to releasing it, the design incorporates both technologies.

Whether creating an intensive or extensive green roof, blue roof water harvesting can form the drainage layer and help to irrigate the planted medium too.

To find out more about green roof systems, please visit the PermaRoof Green Roof division here. Talk to us about combining green roofs with blue systems.

EPDM offers a long-lasting and low maintenance approach to domestic flat roofing. With a life expectancy of more than 50 years, EPDM could outlive some types of projects, such as shed roofing.

Many homeowners must keep a close eye on felt roofs and ensure they are looked after and examined regularly for signs of damage. Common domestic felt is often tacked in place, which is not conducive to keeping water out, so as a result, many shed roofs need to be stripped back and replaced every few years.

EPDM delivers 100% waterproofing performance over its expected lifespan of over five decades and requires little or no maintenance once correctly installed.

Like many other projects, your flat roof will benefit from careful planning, preparation and installation of the right materials. Whether you’re taking a DIY approach or you’re a busy trade roofing professional, PermaRoof UK is here for you.

PermaRoof UK supply EPDM membranes, accessories and high-quality adhesives to help you get the most from your projects – large or small. We support both trade and DIY roofers with a range of roofing and building products, services and technical support from a team of uniquely qualified representatives.

We offer genuine EPDM membranes at the same price as the people that are selling ‘similar’ membranes, that’s right. With PermaRoof price promise, we are guaranteed to be the best priced, for the same product, with a CE certificate, membrane warranty, and the peace of mind that the products are genuine. Why would you need any other supplier?

Here at PermaRoof UK, we offer support and expert advice to guide you through your flat roof projects. We can help you with high performance waterproofing, providing a strong, durable and ultra-reliable base for your blue roof.

We can also connect you with recommended professional local installers via our nationwide network of highly trained, skilled and vetted roofers. Talk to us today.

PermaGroup has established links with some of the biggest names in our industry thanks to our reputation of excellence. Read more about becoming a supplier or stockist here.