Repairing External Cladding: Weatherboarding

ABOVE: A horizontally weatherboarded self-built oak frame home (Read more about this self-build).

Exterior timber cladding comes in many materials and forms, and suits both traditional and contemporary house design. In addition to the common options of softwoods such as Western redcedar and hardwoods such as oak, there are also a number of specially treated timbers and fibre-cement alternatives. The latter are said to have lower maintenance requirements and higher durability than natural timber.

Causes of weatherboarding problems

Being a natural material, timber cladding inevitably weathers over time, particularly if not properly maintained. If you want to keep timber cladding in as-good-as-new condition, stain or paint it every five years in order to protect it from the elements.

If you have carried out regular checks and are on top of the maintenance but a problem becomes evident, check that your rainwater goods are not damaged or blocked, as water penetration through leaking downpipes or guttering is a common cause of the deterioration of timber weatherboarding.

Finally, you might find that the cause of the problem(s) goes back to when the timber cladding was originally fitted. If water penetrates the cladding it must be allowed to evaporate or to run out at the base of the building — otherwise it will cause penetrating damp. To avoid problems, cladding should always be fixed to backing battens, not directly to the wall, and the cavity behind the cladding should be at least 19mm wide. There should also be a ‘splash zone’ of at least 150mm at the base of the house. Finally, horizontally fitted cladding is better at shedding water than that which is fitted vertically.

How to fix it

The easiest way to rectify any damaged areas of weatherboarding is simply to replace them with new boards. Damaged boards can be removed by first prying up the board above to remove the nails holding the damaged board in place, and then lifting it out. You can use the damaged board as a template for the new one. When nailing the new board into place, look for the visible line on the siding where the old board has protected the surrounding boards from fading and use this as a guide when positioning the new board. Use galvanised nails to fix the new board and be sure to protect the existing boards from damage.

Repairing Cladding:

• Brickwork
• Render
• Stone

Further reading:

• All About Weatherboarding
• A Guide to External Appearances
• Cladding: New Façades for Ugly Homes