If your home could have issues with weathertightness, you need to be especially vigilant in your maintenance checks - particularly potentially unsafe balconies, balustrudes, decks, car decks and mould.

Checking for moisture

Make regular inspections part of your normal maintenance routine. In particular look for:

• Any cracks in the finish to the monolithic cladding.
• Separation within any sealant joins.
• Any signs of dampness, mould or musty smells.
• Swelling of particleboard flooring, skirtings or window surrounds.

Watch these problem areas:

• Fascias and gutter penetrating the exterior cladding.
• Where roofs finish within a wall.
• Sill flashings under windows.
• Where balustrades on decks and balconies connect to walls.
• Meter boards (without flashings or sealant).
• Electrical, plumbing and other penetrations.

It is worth noting there is growing concern at the damage that water blasters can cause when used to clean the outsides of houses. If you are concerned that a water blaster has been improperly used on your home, don't wait for the potential leak to cause damage. Have a weathertightness consultant check your home with moisture meters to detect the presence of moisture in walls or the roof.

If you find problems

If you do observe cracking, staining or discolouration, engage a weathertightness consultant to assess the problem before doing any repairs. The New Zealand Institute of Building Surveyors, New Zealand Institute of Architects and Institution of Professional Engineers websites list consultants in each region who specialise in weathertightness problems. These consultants have non-destructive moisture meters which can help find moisture without removing claddings. This is particularly important if you have monolithic cladding and untreated timber framing.

Water damage

The consultant should also be able to advise you on what repairs are needed. You should also look at your options for remedies.

Photograph any damage you find, whether it is a minor repair or something requiring extensive remedial work, and date the photograph in case you need to make a claim later.

Balconies

Look out for risk factors and warning signs that show potentially dangerous rotting around balconies. If these structures collapse from water damage and rot, they could cause serious injury.

During the course of your maintenance check for:

• Deck clearances that will allow water to drain away. There should be at least a 6mm gap between the decking boards and a bigger gap, up to about 12mm, between the house and the deck structure.
• Bolts and flashings for signs of rust which may appear as a blackish staining around the bolt hole.
• The deck surface for slime or mould. This should be cleaned off to reduce the chance of people slipping.
• The step down from the doorsill. It should ideally be about 100mm deep but can be less if the sill is well sheltered.
• A slope on the balcony floor – you can check this by running water onto it and making sure that it runs away to the drain outlet. If it ponds, especially against the building, the balcony should be rebuilt.
• A clear gap (minimum of 35mm or more) between wall claddings and the floor of the balcony to stop water being drawn up into the wall cladding material and wall framing. Clear this gap of any dirt and leaves.
• Cracks in balcony junctions which will allow water in and cause timber to rot. If the balustrade is covered with a proprietary cladding, it is a good idea to seek recommendations for any remedial work from the cladding manufacturer, as it may still be under warranty.
• Drainage – if there are solid balustrades there should be outlets for the water to drain. Clear the outlets and overflows of debris, dirt and leaves.

In all cases, take photographs of any damage or design defects and date them in case you need to seek other remedies.

For more information about decks and balconies, BRANZ Home Series Bulletin 1 is a good source.

Dealing with mould

Be careful when dealing with any timber in your house that appears to be infected with mould. There could be a health risk.

Anybody removing wall lining, particularly if there is a history of dampness, should take care. At the very least facemasks should be used when removing lining and rooms should be well ventilated.

For advice about dealing with mould, read the following PDF on the Department of Labour’s occupational safety and health website. Risks to Health from Mould and Other Fungi (PDF 37 Kb).

Maintaining open timber decks

Open timber decks constructed with durable treated timbers are less likely to be of concern than enclosed balconies. However, the following are things that should be checked.

• Look at where the deck meets the wall of the house. Is there anywhere that water can sit or leak into the house?
•  Do the flashings take water away from the house wall and allow it to drain away?
• If the cladding relies on paint to keep the water out, is that coating continuous or is there any point where water might penetrate?
• Check whether there is any sign of timber beginning to decay.  For example, is there any sign of excessive cracking or 'softness'?
• Is there proper waterproofing around the cantilevered joists or around other joists that penetrate the house wall?
• Are the balustrades or posts correctly connected to the deck or balcony structure? They should not wobble.
• Check the tightness of bolted connections to ensure nuts are secure, especially on balustrades and handrails. Also check where posts are bolted to beams, or where beams are bolted to the house.
• Check that galvanised steel connectors are not corroding.

Maintaining car decks

Car decks are normally constructed with durable treated timbers or from steel and timber. All structures require some maintenance, and from time to time the following things should be checked.

• Check whether there is any sign of timber beginning to decay.  For example, is there any sign of excessive cracking or 'softness'? Timber may appear sound from the outside but, if you are not sure, poke it with a screwdriver to see if it is soft underneath (to do this you may need to look underneath the deck and at where timber meets or runs across other timber).
• Check the tightness of bolted connections on the safety barrier, and ensure they are securely connected to the deck structure.  The barrier should not wobble.
• Check the tightness of all other bolted connections to ensure nuts are secure. These will be between diagonal braces and timber poles or posts, where timber posts and beams are bolted together, or where timber beams are bolted to a concrete anchor point.
• Check that galvanised steel bolts and other metal connections are not corroding.
• Where the deck is constructed with a steel frame, the framework needs to be protected from corrosion. Spots of rust should be thoroughly cleaned and a protective coating applied. If the rust is extensive, you may need to obtain professional advice, for example from a chartered structural engineer.
• Where movement of a car deck is noticeable or seems excessive, or if there is noticeable rotting or corrosion of structural timbers or steelwork, you should close off the deck and not allow it to be used. Immediately get professional advice about what you should do.

Does work on a deck or balcony require a building consent?

It is important that decks and balconies are built in accordance with the Building Code to ensure they are safe for people to use. A building owner should get a building consent for building work on a deck or balcony to ensure that the construction or modification of a deck is checked for compliance with the Code.

A building consent will give assurance to the owner that any safety concerns with a deck are addressed. A building official will have inspected the work during construction and after it has been completed to certify that it meets Code requirements.

Building owners and building professionals should discuss this with their council.

More information

There is useful weathertightness information on the BRANZ website.

See also the BRANZ publication Maintaining Your Home which has information on dealing with problems of weathertightness. You can buy this publication online or contact BRANZ by calling 0800 808 085. The book provides maintenance planning charts and details of how to do regular maintenance tasks and repairs.