roof flashing, Property inspections
Ask the Inspector, Blog, Building Inspection Tips

Roof Flashing: The Hidden Debt Trap!

Faulty Flashing Will Lead To Costly Repairs

Roof flashing is one of those aspects of a property you may never have even noticed. You may have noticed it glinting in the sunlight on your roof, wondered what it was and even thought it was an eyesore. But a thin, carefully installed layer of roof flashing could be the only thing standing between you and an unwanted internal water feature during the next Brisbane deluge.

But if the roof flashing on your property isn’t up to scratch you could find yourself saddled with a damp, mouldy and expensive money pit. Leave roof problems long enough and you could end up with substantial damage and costly repairs.

What is roof flashing?

Roof flashing is an essential part of the process of waterproofing a house. Essentially, it stops water getting into the building via channels, gaps or joins that would otherwise be susceptible to leaks, for example, where a roof cladding abuts an upstairs wall or around vent pipes etc.

The flashing itself is an impervious (ie. waterproof) material installed along the joins in a roof eg. lead sheets etc. Its purpose is to redirect water away from the join, towards a more appropriate escape route such as a gutter or downpipe. This can include joins around protrusions such as skylights, chimneys or vents or around dormer windows. You’ll also find roof flashing around the bottom of valleys (channels) in your roof.

Sometimes flashing is concealed; other times it’s visible… just like the problems it causes if it’s not functioning effectively.

Types of roof flashing materials

Lead sheeting used to be one of the most common materials used in the manufacture of roof flashing and is still used today.  Lead is malleable and easy to cut and shape and very effective. To some degree lead is falling out of favour for use in flashing, especially with the increased popularity of directing run-off to rain water tanks as lead contamination in tank water can have serious implications.  There is also the availability of cheaper and more lightweight products that are also effective. Powdercoated steel flashing and aluminium flashing are much more commonplace now. Roof flashing materials can also be made from a bitumen, zinc or even copper.

Different roof flashing materials suit different types of roofs. Corrugated roof flashing can differ greatly from flat roof flashing, tile roof flashing or slate roof flashing.

What can go wrong with roof flashing?

Roof flashing problems can arise for a number of reasons.

The roof flashing may have been poorly installed in the first place, providing an inadequate, incomplete barrier to water. It may have been poorly shaped for its location or joints in the flashing may be open and not sealed or the flashing may be fretting and cracking with age.

Alternatively, an accumulation of debris; leaves, dirt etc can build up over time and have the effect of diverting water that the flashing is supposed to direct away, resulting in the water pooling and finding an alternative way in. A build-up of moss or other vegetation can also lead to compromised roof flashing. The roof flashing may have even been damaged by rodents or pests such as Indian mynah birds or possums aggressively trying to find a way into the roof space for shelter or nesting purposes.

Damage to the roof flashing can also occur when there is an acute event such as branches or even a tree falling onto the roof. Flashing can also come loose in high winds or be accidentally punctured or damaged when other works are being carried out on the property. Your flashing can be rendered ineffective through the movement of the structure underneath it or by the constant cycle of expansion and contraction in roofing tiles or other materials caused by extremes in temperature.

Finally, problems can also arise when the roof flashing deteriorates over time due to exposure to the elements (eg. rust or oxidisation) and is no longer impervious to water.

Why worry about roof flashing problems?

The main purpose of roof flashing is to keep the house underneath dry. Failed roof flashing simply can’t do this. Water penetration can be a very serious problem in a home. Water will always flow downwards to the lowest point possible, meaning that the damage caused by a leak may not always show up directly where the damaged flashing is located.  It will usually show up as stained ceiling linings or internal roof decay, however, could even be underfoot, rotting your floorboards.

Over time, leaks caused by inadequate or damaged roof flashing can lead to damage to the ceiling linings and even a ceiling collapse.

Water leakage caused by failed roof flashing can cause damp, mould and mildew in a property. Moisture can damage paintwork and rot timber. Mould can also exacerbate respiratory problems such as asthma, especially in immuno-compromised children or the elderly.

Repairing and replacing roof flashing

Some problems can be easily addressed with simple repairs. The materials are readily available at your local hardware store. However, the requisite experience isn’t. For roof flashing to be repaired properly, it’s probably best to call in a roofing expert familiar with, and well equipped for, working at height. To adequately repair or replace faulty, damaged or inadequate flashing they’ll also need to have a fairly extensive understanding of fluid dynamics and how the water will drain away. Simply painting over the mould or mildew just hides the problem and doesn’t address the underlying cause at all, allowing it to progressively worsen.

Unfortunately, many roof problems go completely unnoticed until they cause serious damage, sometimes even structural damage to your home. By that stage, repairs can be incredibly expensive and time-consuming.

Roof flashing and building inspections

Problems with roof flashing can go unnoticed and undocumented if you choose a budget building inspector.

The person carrying out the budget building inspection might not be prepared to get up onto the roof and really look around. They may not be sufficiently experienced to recognise a roof flashing problem when they see it. They might be misled as to the effectiveness of the roof flashing by cosmetic repairs that have been carried out. Damage caused by roof flashing problems may have been concealed under a coat of paint. The inspection may have been carried out over the drier months when the symptoms of the problem are not as evident.

A thorough building inspection should also incorporate the use of a thermal imaging camera and other equipment to detect potential problems areas. It should take hours not minutes and photographs should be taken to document any problem areas.

Experienced, professional building inspector companies like Action Property Inspections understand what is really at stake when your roof flashing is sub-standard.

Your property inspection can be booked online or call Action Inspections today on 1800 642 465.


About Andrew Mackintosh

Andrew Mackintosh has been answering home inspection questions in the greater Brisbane area since 1995. He has personally carried out over 20,000 building inspections and is a licensed builder and licensed building inspector, Member of Queensland Master Builders Association & Institute of Building Consultants. Being the business owner and the inspector, Andrew is passionate about providing clients with excellent customer service, value for money, honest, unbiased, thorough inspection and reporting in a professional and timely manner to allow clients to make informed decisions when purchasing property.

Related Posts