What Is Roof Flashing?

Roof flashing is a crucial component of any roof that protects your building against water intrusion. Installed at your roof’s most vulnerable points, it serves as a key barrier that prevents the potentially devastating knock-on effects of water damage, from rot and mould growth to ceiling stains and infestations.  

But what is roof flashing, how does it work, and which type do you need for your roof? In this handy guide, we’ll walk you through the essentials so that you’re equipped with knowledge of the right materials and required installations for your unique needs.

At Alvadac, we’re backed by 40 years combined experience in providing and installing EPDM rubber roofing and flat roofing, with tailored flashings that secure the lifespan of your roof. For the best advice, contact us today, and one of our experts will be happy to help.   

What is roof flashing made of?

Roof flashing is available in various metal and synthetic materials, each suited to different budgets and roof applications. Finding the right balance between the two is essential for effective waterproofing on your specific roof. 

Metal flashing includes aluminium, galvanised steel, copper, and lead. Aluminium and galvanised steel are the most common choices for residential roofs, due to their high rust-resistance and cost-effectiveness. However, in some cases they may need additional coating to prevent corrosion. This is what differentiates copper as the premium, most long-lasting choice, commonly used on luxury homes, historic buildings, or any roofing project that requires absolute longevity. 

On the other hand, synthetic flashing is popular for self-adhesing and quick repairs, particularly around flat roof joints that don’t require metal fixation to provide a secure and instant watertight seal. Bitumen tape is a commonly used material here, while plastic and rubber flashing are effective for EPDM flat roof installations due to their durability and water resistance.

How does roof flashing work?

Roof flashing provides a strong waterproof seal at the critical points on your roof that are most vulnerable to water intrusion. This includes between roof panels, around chimneys, next to skylights, and where the roof meets a vertical wall on horizontal flat roofs. Once applied, it works like so:

1. Water is pooled away from the vulnerable area safely onto another part of the roof, such as the roof membrane on a flat roof. 
2. Water is prevented from seeping underneath the roofing structure and causing significant moisture-related damage, such as interior staining and structural rot.
3. The watertight seals also provide additional benefits of pest or insect prevention, and in some cases, improved heat retention inside the property.

What is the best type of roof flashing?

Although different compositions of roof flashing may vary in strength, durability, and cost, it’s important you understand the different types of roof flashing needed for the job. Some types are used either separately or in unison with each other, and it all depends on the type of roof being worked on. Let’s take a look at these different types and the applications they are used for.   

Type	Application
Base flashing	Where multiple pieces of flashing are combined to ensure a watertight seal.
Counter flashing	Installed over base flashing, particularly where the roof meets a vertical surface.
Cap flashing	A top flashing layer that deflects water away from pooling next to the vulnerable joint.
Continuous flashing	A long, singular piece of flashing material that protects all joints across the covered area, commonly used on flat roofs.
Step flashing	Overlapping pieces of flashing material that can be bent at 90-degree angles, commonly used on sloped roofs.
Vent pipe flashing	A cone-shaped piece of flashing material specifically designed to seal ventilation pipes.
Valley flashing	Used specifically where sloping roof sections meet, forming a valley-like or ‘V’ angle to protect the joint.
Drip tray/edge flashing	A strip of flashing material commonly used at the base of wall cladding or at the edges of a roof to funnel water away from the joint.

Choose Alvadac for your EPDM flat roofing

Finding the right roof flashing for your requirements is absolutely essential to prevent water intrusion into your property. Getting this right will help you avoid costly and potentially hazardous damage, such as rot and mould; it will also help prevent pests or insects from entering the property. In many cases, it could even improve the energy efficiency of your property! 

To realise these benefits, you need the highest quality materials and precision installation to match. At Alvadac, we specialise in both, delivering first-class EPDM flat roofing services that prioritise excellence, simplicity, and superior customer service. 

For more information on how we can support you with the supply and installation for your property, please get in touch with one of our experts today; we’d be happy to help.  

FAQs

What is another name for roof flashing?

Roof flashing is also known as ‘weatherproofing’, which accurately describes the purpose behind this kind of roof component. The term ‘roof flashing’ is the general description for these materials which prevent water intrusion through the roof of your property. However, different types of flashing are installed depending on the specific roof requirements, such as base flashing, counter flashing, and cap flashing. 

How often should roof flashing be replaced?

Roof flashing should be replaced every 10-20 years as a rough estimate. However, the lifespan of roof flashing entirely depends on the type of material used, the quality of the installation, and any other intrusive factors that affect roof integrity, such as external damage or other works performed on or around the roof. Check if your roof flashing needs to be replaced by getting in touch with Alvadac today. 

Can I replace roof flashing myself?

You might be able to replace roof flashing yourself if you are skilled in roof and/or metal work, you are comfortable at heights, and have a comprehensive understanding of safety procedures. As well as strong installation skills, you also need detailed knowledge of the exact requirements of your roof and the specific type of flashing you need to install. If you are less confident in any of these areas, we advise you to seek professional assistance, not only to ensure your safety, but to provide effective installation that is fit for purpose in protecting your property from water intrusion.