Home Repair

How to Fit a Weatherboard

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    Cedral weatherboard cladding installation is similar to the method described below, with some key differences and problems.

    Cladding battens are larger to increase airflow and must be spaced and screwed in a certain way to prevent boards from rattling in wind. Corners and joints need DPC membranes to prevent water damage to weatherboard cladding. Looking for weatherboard repair? Done! You're covered by Hitch Property Constructions.

    When this cladding isn't installed by a Cedral installer, moisture often gets trapped behind the weatherboards. This moisture is absorbed by the cladding, causing efflorescence, staining, and peeling paint.

    Most people today assume that once the front door of their house, flat, barn conversion, or anywhere they call home is closed, they are weatherproof.

    Depending on the type of front door you have, this may not be true. Without a weatherboard, water and wetness can sneak in under the door.

    Modern uPVC or composite doors are safe. Most of these doors have an integral seal that prevents wetness from entering, but over time, these seals compress and weaken, increasing the chance of wetness getting in.

    What is Weatherboard?

    A door weatherboard is an angled or bevelled piece of wood, metal, or stiff plastic that fits between door jambs (or stiles as they are also known).

    They're most often found on lumber doors to prevent water from eroding the door's face and soaking into the lumber, rotting it over time.

    It also prevents water from entering a home or business through gaps between the door and anything underneath it. This could be a floor, door sill, or threshold.

    In the weatherstrip or drip bead shown below, there is a small recess. This prevents water from leaking backwards.

    Once it reaches the recess, it falls to the floor away from the door.

    Some manufacturers fit a rubber strip in this recess that, when the door is closed, creates a seal between the door and the floor, frame, or threshold.

    If you have an uPVC or composite door, you may not need a weatherboard (although a lot of doors of this type come with one already fitted).

    Many of these doors are fitted into a frame that contains the entire door.

    A spongy rubber seal in the frame prevents water from entering when the door is closed.

    Most uPVC plastic and composite doors are supplied with a weatherboard for good practise as it prevents water buildup along with the seal at the base that can spill in when the door is opened.

    Hardwood and timber exterior doors are rarely fitted with a weatherstrip or board, even though they are designed to prevent water ingress and damage.

    You may need to cut the door to fit, but that's a different question.

    If you have a wooden door, you must buy your own.

    If you've ever seen a steady door (one that can be opened from the top and bottom), you may have also noticed a weatherboard at the base of the top section.

    Types and Styles of Weatherboard


    Wood weatherboards are a standard cladding system available in many profiles and wood species. Horizontal, vertical, and diagonal installation of profiles is possible. They're not usually part of a proprietary system, but some are.

    Radiant pine, macrocarpa, and western red cedar are major species. Macrocarpa and cedar weatherboards can be left natural (but will discolour), but pine must be painted or stained. High UV exposure distorts dark colours.

    All wood weatherboards can be installed over an absorbent or non-absorbent wall underlay, depending on type and finish. Some weatherboard types require treatment for durability. NZS 3602:2003 Timber and wood-based building items covers wood treatment.

    Bevel-back horizontal lumber weatherboards

    Bevel-back weatherboards are a type of cladding that is known for having a moderate amount of air leakage. Even when the boards are fixed directly to the assembly, air can still enter the assembly at the laps and spread throughout the deep spaces created by the lap at the back of the boards. Any water that finds its way into the assembly will either evaporate in the moving air or run down the back of the boards, where it will collect and drain away. In some instances, the water will escape through the laps.

    Shiplap vertical timber weatherboards

    Shiplap cladding is airtight. The thin overlap tends to move and misshape, allowing air to enter at the lap. Rainwater can enter the lap. This distortion also leaks drain pipes.

    Vertical space between the boards, while small, allows airflow and vertical drain. Hitch Property Constructions repairs Melbourne weatherboards.

    Shiplap boards have great potential for air entry, but they don't have the deep space of bevel-back boards because they fit poorly to the wall frame (with a high contact location with the wall underlay).

    Board and batten vertical timber weatherboards

    These systems combine horizontal and vertical boards that are flat, and they cover the board joints with cover battens. This provides an excellent capillary break and restricts the amount of water that can enter the structure. A weather groove needs to be included on the edge of each board, and it needs to line up with a similar groove on the cover battens.

    Additionally, there should be a gap of between 5 and 6 millimetres between each board when they are being installed. This space allows for excellent vertical drainage for water that has leaked through the system as well as for airflow, and it also serves as an effective capillary break.


    Structures, densities, and profiles vary. They're usually an exclusive system that must be installed according to the manufacturer's instructions.

    Fiber-cement boards must be painted to be weatherproof and durable because they are very absorbent. Dark colours distort (although there are some compositions that are more stable).

    Fibre-cement boards are more firmly repaired and stable than wood boards, so the installed system drips less air. Thinner boards have fewer voids at the laps than thicker bevel-back boards. Fiber-cement weatherboards drain and dry less than wood ones.

    Check the manufacturer's weather-tightness installation requirements. Fiber-cement weatherboards or planks can be straightened on buildings with a danger level of 6 or less. E2/AS1 excludes bevel-back fiber-cement weatherboards. The cavity requirement follows E2/AS1 for wood bevel-back weatherboards.

    All fibre-cement weatherboards are vulnerable to:

    • thermal motion
    • wetness absorption
    • moisture penetration at board ends if not properly sealed.


    These come in a variety of profiles, compositions, and integral colours. Usually a clip-together system, they must be installed according to the manufacturer's instructions.

    Thermal movement and UV fading can be a problem. To counter this, they're light-colored.

    The boards are hollow. These spaces, combined with the jointing system, make it a very air-leaky system; water may get in, but drying is good. Non-absorbent boards make a sturdy cladding system. Direct-fixed tiles need an absorbent wall underlay.

    Check the manufacturer's weathertightness setup instructions. UPVC weatherboards can be repaired directly for structures with a danger level of 6 or below. Over a 20 mm cavity, they're installed.

    All UPVC weatherboards are susceptible to:

    • thermal movement
    • brittleness and fading (as a result of UV exposure).

    How to Fit a Weatherboard

    There are many different types of weather bars on the market, from simple wood "drips" to aluminium bars with rubber seals and handicapped-accessible designs.

    Different bars and drips have different recommendations, so read the manufacturer's instructions.

    1. Determine the width of the door and cut any top drip to the width between the door frame stops. This is the external face that is narrowest between the frame, not the jamb. If using a very dry (described below), cut the floor or sill part between the door jamb.

    2. Cut the weather condition bar drips at the end where the door meets the frame on the lock side to prevent jamming when the door is opened or closed.

    It is better to use the Weatherten bar (one of two types shown opposite) instead of the wood weather condition drips (shown below), which are very traditional and are typically fitted to the face of the door at the bottom rail. The bottom of the weather type bar is fitted between the door and the doorstep or sill and integrates a drip that interlocks when the door is closed.

    3. Stain/prime/undercoat

    Before installing, stain or prime and undercoat the entire strip to provide weather protection and ensure it lasts a long time.

    Before applying your protective finish, lightly sand it with 240+ grit sandpaper to remove any rough edges and to help your final finish stick. Hitch Property Constructions provides Melbourne weatherboard repairs.

    If staining, apply your first coat over everything, making sure to cover all nooks and crannies. Allow to dry for the manufacturer's recommended time before applying second or third coats.

    If priming/undercoating, use your guide and let it dry before using. Check the manufacturer's instructions about multiple coats.

    Finish painting when primer and undercoat are dry. This will match your door's finish. You're responsible.

    FAQs About Weatherboard

    Usually the termination of this type of weatherboard is handled with a corner piece or elements such as window or door frames. Shiplap weatherboards have a more complex tongue-and-groove shape that allows for the installation of a flat, weatherproof cladding.

    The Weatherboard Screws feature self-drilling tips, box threads and a trim-head profile which facilitate the screws being installed into weatherboards without the need for pre-drilling in most instances.

    Before we start getting into details, we highly recommend talking to a professional builder as completely replacing rotten weatherboards and recladding your home is not an easy task and it required a builders licence, if performed incorrectly it will cause further damage to your home.

    Due to the movement timber weatherboards can experience through both high and low concentrations of moisture, filling the underlap can cause problems.

    Stainless steel nails are recommended for the application of roof shingles, shakes and cladding, particularly Western Red Cedar, Siberian Larch and other wood species with a high tannin content.

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