Is an old concrete tile roof worth restoring and painting?

An old concrete tile roof is usually worth restoring and painting if the tiles are still strong enough to walk on, the leaks are traceable to specific broken tiles or failed ridge mortar, and the timber underneath is sound. It is not worth it when the tiles are crumbling, breakages are widespread, or the roof leaks for reasons paint cannot reach, because a coating protects tiles but does not make a failing roof watertight.

Restoration is a repair job with paint at the end, not a paint job. Most of the value is in the work before the first coat.

What does a tile roof restoration actually involve?

A proper restoration has four parts, in this order.

1. Cleaning

Weathered concrete tile roofs are, in Resene's words, typically infested with mould, widespread lichen and moss, and removing them is critical to a coating that lasts. Resene's published process for weathered tile roofs is:

1. Rake out joints and tile overlaps to remove built-up debris, and scrape off large clumps of moss.
2. Spot treat heavy lichen with a moss and mould killer.
3. Apply a slow-release biocide wash a few weeks before painting, ideally in overcast conditions, so the growth dies off fully.
4. Water blast at the maximum pressure that will not damage the tiles.
5. Let the roof dry thoroughly. Disconnect downpipes during cleaning and clean out the gutters before reconnecting them.

One practical caution of our own: when water blasting, keep the jet from driving water up under the tile laps, or you create the leak you are trying to prevent.

2. Ridge rebedding and repointing

Ridge caps sit on a mortar bed and are sealed along their edges. On older roofs that mortar cracks and lets go, and in our experience loose ridge caps are a frequent cause of leaks on older tile roofs. Cracked pointing over a firm bed can be repointed. A ridge cap that rocks when you press it needs lifting and rebedding. This must be done before coating, because paint over loose ridges just paints over the leak.

3. Replacing broken tiles

Cracked and broken tiles are swapped out for matching ones. Concrete tile profiles vary, so a roofer may need to source second-hand tiles of the same profile, or take tiles from a less visible part of the roof and put the replacements there.

4. Sealing and coating

For weathered, unpainted concrete tiles, Resene's system is a seal coat of its solventborne Sureseal followed by two coats of Summit Roof. Where tiles have been painted before and the coating is sound, it notes the sealer is not needed and two topcoats are enough. Previously painted tiles that are flaking need the unsound paint removed first, and the sealer may differ depending on the surface, so ask the supplier to specify it.

Will painting stop a tile roof from leaking?

Not on its own. Resene answered this directly when a homeowner asked whether painting would seal a leaking tile roof: painting can assist with weathertightness, but if the source of the leak is not repaired, leaks will still occur, because roof paint is vapour permeable. It is designed to let moisture vapour escape, not to act as a waterproof membrane.

That is why ridges and broken tiles come first. If a roof is still leaking after those are fixed, the problem is likely below the tiles, in the underlay, flashings or valleys, and a roofer needs to look at it.

What are the signs a tile roof is past restoring?

What you find	What it usually means	Verdict
Faded, mossy, a few cracked tiles, loose ridge mortar	normal ageing	restore
Bare concrete with no coating left, surface slightly sandy	the tile surface is weathering	usually restorable, with a penetrating sealer first
Tiles that crack or crumble when walked on carefully	the concrete itself has lost strength	get a roofer's opinion before spending on coating
Broken tiles across large areas	widespread tile failure	replacement is often better value
Leaks with no broken tiles or ridge fault	underlay, flashing or valley problems	roofing repair first; paint will not fix it
Sagging lines along the roof	structural movement in rafters or battens	builder or roofer, not a painter

Friable tiles are a judgement call. Resene has advised on a roof of 50-year-old tiles that had lost all coating and become friable but could still be walked on gently: it supported a penetrating sealer and two topcoats to extend the tiles' life. That is a reasonable way to buy time on a roof that is structurally fine. It is not a way to rescue tiles that snap underfoot.

How long does a restoration last?

In one published answer about a weathered tile roof painted with its system, Resene's technical team said it would expect a repaint to be needed at around the 10 to 15 year mark. How close you get to the top of that range depends on exposure, the colour you choose, and whether moss and lichen are kept under control afterwards.

The cheaper alternative some people ask about is a clear water repellent. Resene mentions its clear repellent as an option for weathered tiles, but notes it needs a maintenance coat every two to three years and it will not change the colour of a faded roof.

Restore or replace: how do you decide?

Get the roof inspected before you get a painting quote. The questions that decide it are simple: how many tiles are broken, can the tiles take foot traffic, what state are the ridges in, and is the underlay still doing its job. If the answers are mostly good, restoration buys years for a fraction of the disruption of reroofing. If the tiles themselves are failing, putting coating on them only postpones a bigger bill.

Our article on roof painting versus replacement goes through the trade-off in more detail.

Our tile roof painting page explains how we prepare and coat concrete tiles.

Tile roofs are also not a place to learn on. Tiles break under the wrong footstep, and wet moss is slippery. If you would like an honest assessment of whether your roof is worth restoring, contact us for a free quote.