Signs Your House Needs Recladding, and How It's Tested

Paint over a stain under a window and watch it come back. That's not a paint problem. That's water getting in from somewhere. Whether you end up with a small repair or a reclad depends on what's behind the wall, so the first job is finding out how bad the damage is. Decisions come after.

Signs you can see from outside

Pick a dry day and walk around the house. Start at the window corners. That's where the cladding meets the joinery, and joins are where most leaks start. Then the base of the walls. Then anywhere a deck or balcony meets the cladding. The government's buyer guide, Learning about leaky buildings, lists most of what follows.

• Hairline cracks running out from the corners of windows and doors
• Rust marks or staining on the wall, or paint that bubbles and peels in the same spot every year
• Sealant around windows and doors that's split, shrunk or gone altogether
• Cladding with no gap between it and the ground, or between it and a deck
• A deck that's higher than the floor inside the house
• Garden beds banked up against the wall
• Timber around window and door frames that's soft, damp or rotting

Any one of these can be minor. A failed bead of sealant is a cheap fix. Two or three in the same area is different, and so is a problem that keeps coming back in the same spot after you've repaired it.

Signs inside the house

Inside the house the signs are easier to miss. It's a smell here and a stain there, each easy to explain away, so people live with them for years.

• A stain on a ceiling, or on the wall under a window
• A musty smell that's still there after you've aired the room
• Mould spots on an interior wall
• Swollen or cracked skirting boards and architraves
• Spongy flooring, or walls that give when you press them
• Damp or water-marked carpet

Condensation and roof leaks cause some of these too, which is why guessing from inside the house isn't reliable. A smell or a soft patch next to an outside wall, near a window? Get that checked.

Your house's age and construction

The age and construction of the house matter as much as any stain. The highest-risk period is the late 1980s to the mid 2000s, for homes with monolithic (plaster-style) cladding. We go through what went wrong in that period in our guide to why 1990s and 2000s Auckland homes need recladding. The short version: the cladding was fixed straight onto the frame with no cavity for water to drain, and from the late 1990s the framing was often untreated. The Ministry of Business, Innovation and Employment (MBIE) says in its guidance that homes built between 1998 and April 2004 were often framed in untreated kiln-dried radiata pine, and untreated timber doesn't last once it gets wet.

Design matters too. Houses with minimal eaves or flat roofs let more rain reach the walls, so every sign above is more serious in a house like that. Weatherboard and brick houses from the same years aren't immune, but they don't have the same built-in weakness as a direct-fixed monolithic wall.

Why you can't judge it by looking

The frustrating thing about a leaking wall is that the damage is usually hidden. Water gets in at a window corner, runs down inside the wall and sits against the framing. The cladding can look fine for years while the timber behind it decays. MBIE's guide to the diagnosis of leaky buildings says the damage may not be obvious from a visual examination. That cuts both ways. A clean-looking wall isn't proof of a dry one, and a cracked one isn't proof of rot.

How a suspect wall gets tested

Testing happens in stages, and each stage only goes ahead if the one before it shows it's needed. The sequence below follows MBIE's guide to the diagnosis of leaky buildings.

1. A visual check, inside and out. The places where water tends to get in, such as window corners and joins between materials, get a close look, and the house's history and paperwork are pulled together.
2. Non-invasive checks. A moisture meter is run over the outside of the walls to find areas with high readings. The readings are a guide only. They don't measure the actual moisture in the timber, and recent weather can affect them. A high reading means a closer look is needed. It doesn't confirm rot.
3. Invasive testing. Small holes are drilled at the suspect spots so moisture can be measured in the timber itself and the framing can be checked directly.
4. Destructive testing, only where it's needed. A section of cladding is opened up to show the condition of the framing and how far the damage has spread.
5. A written report. The last stage. It says where water is getting in, how far the damage goes, and what the repair should be.

Because the testing is staged, walls that test dry don't get opened up. And because it ends in a written report, you have a record of what was found and where. That record is what a firm quote gets built on. Our guide, how we quote a reclad, explains how the price is worked out from it. If you've been handed a report, our guide to how to read a weathertightness report explains what's in one.

What the results mean

A bad result doesn't automatically mean a full reclad. The findings usually fall into one of three groups.

• Contained damage. Water's getting in at one or two spots, say a window corner or where a deck is fixed to the wall, and the framing around those spots is sound or only slightly affected. A targeted repair sorts it.
• One or two walls. The damage is mostly on one or two sides of the house, usually the sides that take the most weather. A partial reclad of those walls can be the right answer. Our guide to partial or full reclad covers what decides it.
• System failure. The damage is widespread because of how the walls were built. That's typical of direct-fixed monolithic cladding with no cavity. Patching one spot doesn't fix it. This is where a full reclad is the right answer.

Which of the three applies to your house determines what it costs. The reclad cost guide shows the typical price range, and our guide, reclad or demolish and rebuild, covers the harder call when the damage is severe. A full reclad needs a building consent, which we cover in our guide to reclad building consent in Auckland.

What to do in the meantime

Don't paint over a stain, and don't just reseal a joint and call it fixed. A fresh coat of paint or sealant hides the stain without fixing the cause. Take dated photos of anything you notice, especially after heavy rain. Photos of the same spot over a few weeks show whether a stain or crack is growing. If water is already coming in, our guide on what to do when your home is leaking covers the first steps.

Questions people ask

How many signs mean I need a reclad? There's no magic number. One sign on a recent weatherboard house might just be worn sealant. One sign at the window corner of a 1999 plaster house might be the start of something bigger. It's the signs together with the age and construction of the house that count, and only testing settles it.

Can I check my walls myself with a moisture meter? You can look for the signs above and keep photos. A hand-held meter reading on its own isn't conclusive, though. MBIE's guide treats meter readings as indicative only, and a normal reading on a dry day doesn't clear a wall that has other signs. The answer comes from staged testing.

I'm buying a house with some of these signs. What now? Get an independent weathertightness inspection before you go unconditional, and ask the agent whether leaks or weathertightness problems have been reported. The buyer guide above says an agent is expected to know about this risk and tell you. Our guides to buying a monolithic-clad house and reading a LIM for weathertightness risk go through what to check.

Seen one of these signs on your own house? Send us three photos for a free visual inspection: one of a window corner, one of the wall below a sill, and one where the deck or balcony meets the wall. Text them to 021 701 664 or email info@adronconstruction.co.nz, and we'll give you a straight read on what we see and what we'd recommend from there.

For the whole process, from first assessment to the Code Compliance Certificate, see our complete recladding guide, or read about how we approach residential recladding in Auckland.