Internal flashings to deflect & drain moisture at key joints & penetrations

 While leaks primarily occur around windows and doors, they also occur at other joints and penetrations of the cladding and trim. The NZBC therefore requires flashings be installed in order to ensure weathertightness and maintain the overall health of the building.  Internal flashings provide a moisture barrier and drainage plane that prevent moisture build up and deflect moisture to the building exterior.  All Redway Internal flashings are manufactured from corrosion resistant, UV protected uPVC, and are available from all leading building merchants. 


• All Internal Flashings are manufactured from rigid uPVC and are supplied in 2.7m lengths unless stated otherwise.
• All products are biologically and chemically resistant to treated materials such as framing timber. They will not rust nor react in salt zones.
• The uPVC compound is stabilised for UV protection as required by the NZBC.
• It is lightweight allowing for easy transportation and installation.


Building corners are prone to water leakage due to shrinkage of corner boards, wind exposure and leaky gutters. Installation of corner flashings are therefore a requirement of the NZBC to ensure weathertightness and prevent building deterioration. 

Redways uPVC Corner Flashings are available in 3 sizes (55mm x 55mm, 85mm x 85mm and 105mm x 105mm) and are a simple, yet effective flashing solution. All corner are 2.7m in length. An additional advantage of the Redway design is that every corner flashing is reversible and therefore can be used as either an Internal or External corner, giving the installer added flexibility in usage. 

Each Corner should be installed behind the cladding in either a direct fix or cavity situation as seen in the example detail of the right.

View and download available Corner Flashing details in PDF & DWG




Back Flashings (or Flat Back Soakers) are designed to provide a second line of defence behind a vertical control joint to prevent moisture from entering the cavity due to shrinking of the cladding boards.

Redway uPVC Back Flashings are available in 3 sizes (40mm, 135mm and 160mm) with all profiles supplied in 2.7m lengths.

Each Back Flashing should be installed vertically behind the cladding joint.

View and download available Back Flashing details in PDF & DWG



NEW: 50mm Flatback Jointer

Six flexible rubber like flanges create a tight seal when nailed behind a panel joint, regardless of nail position.
A small (2mm) protrusion on center aids quick alignment of panels

Sold in 2400mm lengths 




Cavity to Non Cavity Soakers are designed to be installed behind a vertical cladding junction in a situation where one cladding has a cavity and the other is fixed directly to the stud. The flashing is designed to prevents water intrusion and creates a drainage plane should the seal fail. 

Redway uPVC Back Flashings are available in 3 sizes (50mm x 19mm x50mm, 50mm x 42mm x 50mm and 50mm x 19mm x 100mm) with all profiles supplied in 2.7m lengths.

 View and download available Cavity to Non Cavity Soaker details in PDF & DWG






When water runs down a window, on a windy day it can often be blown back over the sill and into the cavity. To prevent this water from reaching the dry side of the cavity and potentially causing damage, the Redway Brick Kickout Flashing deflects this water and directs it to the wet side of the cavity, away from the building to drain clear.

View and download available Brick Kickout Flashing details in PDF & DWG.

NEW: Vertical Joint Flashing 

uPVC extrusion installed behind cladding at vertical joints. At only 1/4" in height, the flashing produces a negative, shadow gap for a modern look. The extrusion features 6 flexible flanges to provide a tight air & water seal. 



Available in 7mm. Coming soon 17mm