Checklist

Our checklist identifies the things you should look out for if you are buying a house at risk of being a leaky building.

If you already have a home with monolithic cladding these are also the things you should look out for when doing routine maintenance.

Interior

Tell-tale signs that water is getting inside a house include:

• Black spotted mould on inside walls or ceilings (mould may also form on walls and ceilings because of internal moisture).
• Swollen architraves or MDF skirtings.
• Stained timber window or door trims.

  The only sign that this was a leaky building was a small damp patch on the carpet (Photo:BRANZ Ltd)

• Stained carpet.
• A general feeling of dampness next to doors or below windows.

If the damp is caused by moisture build up from within the house see Combating dampness.

Exterior

Cladding
Pay particular attention to corners and junctions in the cladding. Remember monolithic cladding relies on the paint coating to keep your home weathertight.

Look for paint that has:

The results of water entering (Photo Prendos)

• Cracks.
• Worn areas.
• Surface bubbling.
• Ridging.
• Peeling. 
• Any signs of lifting or de-lamination.
• Thin or transparent areas, particularly on exposed corners.

If you see any of these problems, the paintwork probably needs re-coating. Get advice from a building expert to ensure the problem is only with the paint and not an indication of a failure in the underlying cladding material.

The only exterior signs of failure in an enclosed deck (Photo:BRANZ Ltd)

Penetrations to walls
Check around the meter box and any pipes penetrating the wall cladding to ensure they are flashed or sleeved.

Decorative features must not penetrate the cladding and all fixings should be sealed.

Check where fascias and gutters meet a wall surface. The paint finish should be continuous behind the end of the gutter and the roof junction should be flashed.

The pipe has not been flashed where it penetrates the wall (Photo:BRANZ Ltd)

Roofing
The roof should be checked for build up of debris that could track or hold water.

• Ensure all flashings are securely fixed and provide a secure overlap to the roofing, especially around penetrations from flues, vents and other services. If in doubt get the advice of a reliable roofing company.
• Check the clearance of claddings from the roof surfaces and flashings. It should be possible to easily run your hand under the cladding to enable the underside to be re-painted when needed.
• Ensure that there is a kick-out where a roof ends in a wall surface.

Under or over windows

• Check for missing flashings, particularly head and sill flashings. If they are fitted they will be visible on the outside.
• Check the flashings to ensure they slope to the outside to spill water over the window or door-frame. Check at the ends to ensure they will not allow water to flow inwards at their ends.
• For curved windows check that the flashing has a stop-end to direct water to the exterior and not allow water to enter behind the wall cladding.
• Check the jambs to ensure they are sealed to the cladding.
• Check the corners of cladding on recessed windows – particularly check that there are no hairline cracks in the paint finish.

Solid handrails
These are problem areas that can contribute to leaky buildings.

The texture coating to this balustrude has failed (Photo:BRANZ Ltd)

Where the texture coating is carried over the balustrade leaks may not be visible. If you are unsure contact a building consultant for advice. The most reliable check is to measure the moisture content of the timber framing. This is best done using a moisture meter with probes through two small holes in an area that is not exposed. The timber floor structure should also be checked from the underside.

At ground level
Check the clearance of the cladding from the ground. Options may be to lower a built-up garden area or provide paving that falls away from the house, but if this is not possible seek expert help.

Check doorways and imagine how any flooding or puddles of rainwater might affect the doorway. Water does not need to flow through the doorway to cause problems, but may flow under the sill. It is possible that water might also enter through splashing. The ground may need to be re-contoured, or in the worst case, doors removed and raised.

No cladding should go right into the ground (Photo:BRANZ Ltd)

Decks
Ensure there is space between timber decks and cladding. It is important to regularly remove leaves and other debris caught up in the gaps.

Waterproof decks should have no areas of lifting membrane. Joints should be tight and there should be no water ponding anywhere on the surface. The membrane should have a positive coving at all edges, including under doors. Check for nicks in the membrane.

Paint-on membranes require regular checking and may become punctured even with a protective layer of tiles. Have these membranes checked annually and do not put off re-coating if the membrane is wearing.

This deck has cladding touching the surface, drawing water up behind the cladding - the stain is a result of decaying wall framing (Photo:Longman)

Make certain all drainage and overflows are clear. The overflow height should be at least 50mm below any floor area, and below any deck coving at walls or doorways.
If you have any doubts, seek expert advice. Some decks have been constructed with untreated timber and may become dangerous if moisture has got into the framing.

If you suspect that your home has weathertightness problems, seek expert advice and see What to do if you have a leaky home for more information.