Example of apron flashing correctly fixed.
The verticle portion is behind the cladding.
Example of apron flashing incorrectly fixed.
The verticle portion is not behind the cladding.
Not putting flashing over windows causes rotting
Smartform curved flashing
Flashtite roof penetration flashing
Keeping water outside your home
Flashing in some form or another has been keeping our homes water tight for thousands of years. Over the last century roof designs and flashing solutions have been relatively simple. More recently, with many new home-owners demanding interesting roof lines, simple solutions are often insufficient. So how do you ensure the rain is kept out?
This article will provide you with a solid understanding about flashing types and materials, and which one is most suitable for your job.
Where is flashing used?
Flashing is used where construction elements intersect; for example: roof planes and walls, protruding elements such as chimneys, ventilation outlets, skylights and dormer windows. It is where these elements meet that flashing of some kind is required to ensure there will be no water penetration into the structure below.
Types of common flashings
Curved flashing will be required when you need to flash something that is round or curved like a fire flue or roof post. Regular sheet flashing will not work in these cases as it cannot be stretched. Tape products or roof-tites are your only options. Your local hardware stores, including Bunnings and Mitre10, will supply these.
Sheet flashing may be exposed or concealed depending on what product you choose. The most common types of flashings are made of
metals such as lead, galvanised steel and aluminium, and not so commonly,
stainless steel, copper and zinc alloy (due to cost factors). More recently rubber and synthetic materials are proving
very popular as they are lead free, easier to install and are often more cost effective.
BTW You can use any type of product for flashing as long as it is watertight, long lasting, malleable, rust resistant, and non-corrosive.
Aluminium is popular as a flashing material because it easy to work with and cost effective. Note: Aluminium may react chemically with cement mortar.
Copper is very easy to work with and can be mended easily by soldering. Copper flashing is more expensive to install, but as a result of copper's longevity it is very cost effective over the lifetime of a building. Copper will react with galvanised steel components. Soft copper can be specified where extreme forming is required, for example in the case of complex roof shapes. Copper may cause staining on other materials.
Galvanised steel flashing
Galvanised steel is less malleable than other products, but is very inexpensive and used in many 'apron' type flashing situations (see examples above). Apron flashing is generally used in concealed locations such as roof valleys and roof to wall junctions; for example: along the front of a dormer windows and around chimneys.
Apron flashing is very sturdy and acts like a concealed gutter, holding and directing water to an open space where it can flow away. You need to be aware that different metals can react with steel and will cause corrosion.
Lead flashing is still commonly used as it is easy to work, economical and readily available. But lead can cause major health problems. It should be noted that lead flashing can tear easily during installation, which can lead to leakages. Lead flashing may also react chemically with cement mortar.
Wakaflex lead free flashing.
Available at your local hardware store.
Fastfix aluminium reinforced
butyl flashing repair tape
Synthetic tapes are the latest in fast and effective high grade waterproofing solutions. Tapes are great for the DIYer and building professional.
Bitumen & rubber flashing
These products do not react with other materials. But some of these flashing materials can deteriorate with exposure to sunlight.
Manufacturers are now combining tradition flashing products to improve the longevity and installation time of flashings. Evo Building Products have a flashing product called Wakaflex that is made from aluminium and is coated with butyl rubber.
Wakaflex is a quick and easy to use product for roofing professionals or the DIYer. Take a look at this video for more information.
Butyl rubber has exceptionally low gas and moisture permeability and outstanding resistance to heat aging, weather, ozone, chemical attack, flexing, abrasion and tearing.
Flashing repair products
Flashing repair products come in many forms. A popular brand sold through Bunnings and Mitre10 is called Fastfix.
Where to buy
All the products described above can be purchased from your local hardware store including Bunnings and Mitre10.