It usually starts with someone else on your roof. The solar installer finishes up, or the antenna bloke comes down the ladder, and a week later you spot a brown ring on the ceiling. Or a branch comes down in a westerly and you can see from the driveway that something is not sitting right. Cracked roof tiles are one of the most common things we get called out for across the Mornington Peninsula, and the good news is that most of them are a small, quick fix if they are caught early.
The bad news is that a crack you can barely see can still let in a surprising amount of water. Here is how we look at it.
One crack really can let water in
A roof tile works by overlapping its neighbours so rain runs down and off the roof. When a tile cracks right through, water that should run over the top now runs into the gap and drops underneath.
What happens next depends on what is under the tiles. Newer homes usually have sarking, a reflective foil or membrane laid under the battens that catches stray water and carries it to the gutter. Plenty of older Peninsula homes have none. On those roofs, water from a cracked tile lands straight on the insulation and the plasterboard ceiling. You might not see a stain until the insulation is soaked through, which can take a few storms.
Even with sarking, we would not leave it. Sarking ages, gets torn by tradespeople and can sag between battens, so it is a backup, not a fix.
Hairline crack or a proper break: how to tell
Not every mark on a tile means trouble. From the ground or a ladder at the gutter line (please stay off the roof itself), here is roughly how we sort them.
- Surface crazing: fine web lines in the glaze or coating, common on older terracotta. Usually cosmetic.
- Hairline crack: a single thin line that does not go all the way through. Worth watching, and worth replacing if it sits in the water path.
- Through crack: the tile is split into two pieces, even if they still sit together. This one leaks.
- Chipped or missing corner: the overlap has gone, so wind can push rain under the tile next door.
- Slipped tile: not cracked, but sitting lower than its row. Often a sign of a broken nib (the little lug that hooks over the batten).
If you are seeing water inside but cannot see an obvious crack, the problem may be somewhere else entirely. Our post on why a roof only leaks in heavy rain covers the other usual suspects, such as valleys and flashings.
Most cracks have a very ordinary cause
Tiles are tough against weather and surprisingly fragile underfoot. The single biggest cause we see is people walking on them the wrong way. Solar installers, antenna and satellite techs, air conditioning installers and well meaning owners cleaning gutters all put weight in the middle of a tile instead of on the overlap, where it is supported. Concrete tiles snap. Terracotta cracks.
On the Peninsula, a few other causes come up again and again:
- Branches dropping in strong winds, especially under the big gums and cypress around Mount Eliza and Red Hill.
- Hail, which tends to chip edges and crack older, more brittle tiles.
- Age. Concrete tiles slowly lose their surface coating and get porous, and old terracotta gets brittle.
- Movement at the ridge. When the bedding and pointing under ridge caps break down, caps and the tiles beside them can shift and crack.
That last one is worth a closer look if your cracks are clustered along the top of the roof. We have a separate guide to the signs your ridge caps need repointing.
Sealing a crack is a stopgap, not a repair
Yes, you can glue or seal a cracked roof tile. Roofers use flexible sealants and butyl tape on the underside or top of a tile when a replacement is not on hand, and it will often hold for a while. We do it ourselves as a temporary measure before a storm.
The trouble is that sealant does not last like a tile does. Sun, heat and the constant expansion and contraction of the roof break it down, and a sealed tile is still weaker than a whole one. On a roof that gets salt spray and strong winds, as many around Rosebud, Rye and Mount Martha do, we treat sealing as a way to buy time, not as the answer.
Replacing the tile is the proper fix. A roofer lifts the tiles above it, slides the broken one out, and slots a sound tile into place. On most roofs it is a short job once the right tile is on hand.
Finding a matching tile is the hard part
This one surprises people. The work is quick, but finding a tile that matches can take longer than fitting it. Many profiles on older Peninsula homes have not been made for decades, and colours fade over the years, so a brand new tile in the same range can still look patchy.
We usually work through three options. First, any spares left in the garage or roof space from when the house was built, which are worth keeping if you have them. Second, secondhand tiles from salvage suppliers. Third, borrowing a tile from a spot nobody sees, such as under a solar panel or on a back section of roof, and putting the closest new match there instead. Concrete and terracotta do not mix well, so the match needs to be the same material as well as the same shape.
Sourcing the right tile is part of the job on our tile roof repair service, so you do not need to ring around tile yards first.
When a handful of cracks points to something bigger
One or two cracked tiles after a solar install is a simple repair. A dozen spread across the roof is telling you something else. If tiles are cracking without anyone walking on them, or the ones we lift crumble at the edges, the roof may be reaching the point where patching becomes a cycle.
That is when we talk about a restoration, which usually means replacing broken tiles, rebedding and repointing the ridges, cleaning and recoating, or in some cases replacing the roof altogether. We will tell you honestly which camp your roof falls into. Most of the time it is the simple fix.
What to do this week if you have found one
Do not climb up to look closer. Tile roofs are slippery, especially with lichen or morning dew, and you can crack more tiles than you find. Take a photo from the ground or the top of a ladder at the gutter, check the ceiling and the roof space below that spot for damp, and put a bucket under any drip.
If rain is forecast, ask for a temporary seal or tarp. If the crack came from storm damage, take photos before anything is moved, because your insurer will want them. Wear and tear is generally treated differently from storm damage, so check your policy wording.
Got cracked tiles? We can sort it
If you have spotted a cracked or slipped tile, or a stain that could be one, we can come out, find the cause and swap the tile with a matching one. Book a visit through our tile roof repairs page and we will take it from there.
Common questions about cracked roof tiles
Is a cracked roof tile a problem?
Usually, yes. A tile that is cracked right through lets rain run underneath, and on homes without sarking that water goes straight onto the ceiling. A fine surface crack is less urgent, but it is worth having it checked before winter.
Can you fix a cracked roof tile without replacing it?
You can seal it with a flexible roofing sealant or butyl tape, and that will often stop a leak for a while. It is a temporary repair. Sealant breaks down in sun and heat, so we recommend swapping in a sound tile as soon as a match is found.
Can cracked roof tiles be glued?
They can be bonded with roofing sealant, but glue does not restore the tile’s strength, and the joint will eventually fail. Treat it as a way to get through the next storm, not as the final fix.
Will a roof leak with one tile missing?
In most rain, yes. A missing tile leaves an open gap in the roof, and wind driven rain will get in even on a light shower. If there is sarking underneath it may hold for a while, but the gap should be covered quickly.
How much does it cost to repair roof tiles?
It depends far more on access and finding a matching tile than on the tile itself. A single tile on an easy single storey roof is a small job, while a steep two storey roof or a discontinued profile takes longer. Any roofer should be able to give you a firm price once they have seen the roof.
