How Do You Know If Your Roof Has Storm Damage in Cwmbran?

Start With the Street, Not the House

Designated a New Town in 1949 and laid out over the decades that followed, Cwmbran went up in programmes rather than one house at a time. Whole neighbourhoods share a build date, a specification, a roof covering and a detailing method.

Roofs built together age together. The ridge mortar went on in the same year, the underlay is the same age and the fixings came off the same specification, so they arrive at the end of their service life within a few winters of each other.

That has a practical consequence that is genuinely useful and costs nothing to act on. Walk to the end of the road and look at the roofs of the houses built with yours.

• Have any of them had ridge work done recently? Fresh mortar or a new dry-ridge system stands out clearly against the rest
• Are any showing a ridge tile out of line, or a gap at the verge?
• Has anyone had scaffolding up in the last year or two?
• Are several roofs showing the same thing in the same place?

What to Look For on a Concrete Interlocking Tile Roof

The predominant covering across Cwmbran's postwar housing is concrete interlocking tile, and it fails differently from the slate on older valley housing. The tiles themselves are robust; the system depends on them holding each other.

Tiles are laid so that neighbours overlap and interlock, with mechanical fixing typically at the perimeter and intermittently across the field of the roof. So the signature of damage is not a single clean gap. It is displacement.

• A tile sitting at a different angle from the ones around it
• A tile that has ridden up so its edge stands proud of its neighbour
• A run of tiles out of line, spreading from one starting point
• A gap at the verge — the sloping edge at the gable — where the perimeter fixing has let go
• Broken tile on the ground, since concrete tile tends to break rather than slide

That third one is the important pattern. Because interlocking tiles restrain one another, losing one takes support away from its neighbours, and damage spreads outwards from a single failure rather than appearing at random.

Shallow Pitches Need a Different Look

Postwar planned housing used much shallower roof pitches than the housing that came before it, along with mono-pitch designs, canopies over entrances, integral garages and flat-roofed links between blocks.

A shallow roof sheds water more slowly than a steep one, which makes it less forgiving of a defect. It also means driven rain can be pushed up the slope against the direction of fall, into laps that a steep roof would never expose.

• Look at the laps between courses for any tile sitting less deeply than the rest
• Check the eaves course, where a shallow pitch delivers the most water
• Look at the flat and mono-pitch elements — the canopy, the garage roof, the link between blocks. These are frequently the oldest covering on the plot and the last thing anybody inspects
• Check where a flat section meets a wall, at the upstand, which is where flat roofs almost always fail

The Ridge and the Verge

Sight along the ridge from as far back as the plot allows. It should be dead straight and evenly spaced. Mortar-bedded ridges from the middle decades of the last century are now well past the point at which the bond can be relied on, because thermal movement cracks it long before anything visible happens.

The verge is the other line worth a look. On these roofs it is either mortar-bedded or fitted with a dry-verge system, and dry-verge is made of components: clips break, unions crack and end caps detach. A missing end cap on a verge is a small thing that lets wind straight under the edge of the roof.

From the Loft

Daylight, wet timbers, damp insulation, staining or tears in the underlay, and daylight around anything that passes through the roof. Go in daylight, stay on the joists, and do not go at all if the ceiling below is bulging or dripping.

On housing of this age there will normally be underlay beneath the tiles, which is a real advantage: it means a displaced tile does not put water straight onto the timbers. What matters is whether the underlay is intact. A tear in it, particularly near the eaves where it has been exposed to sunlight through a gap, removes the second line of defence and turns a minor tile problem into a genuine one.

Has Your Roof Already Been Re-Covered?

Worth establishing, because it changes every answer on this page, and a surprising number of people do not know.

Estate roofs get done in batches, sometimes by a landlord or a housing association across a whole block at once, and a re-covering carried out twenty years ago resets the clock. From the ground you can usually tell: a different tile colour or profile from the houses either side, a mechanically fixed dry-ridge or dry-verge system rather than mortar, newer-looking fascia and guttering, or a ridge line that is noticeably cleaner and straighter than its neighbours.

If yours has been done and the roofs around it have not, the neighbours-as-evidence approach above does not apply to you and you are in a better position than the street suggests. If theirs have been done and yours has not, the opposite is true, and that is worth knowing before the next storm rather than after it.

What This Will Not Find

Wind loosens tiles without removing them and fatigues fixings that then fail weeks later in a much smaller wind. That is why a roof can come through a named storm looking untouched and lose tiles in an ordinary gale a month afterwards.

If your property came through something severe, an assessment is worth having even when nothing appears wrong — and on an estate where the roofs share an age, it is worth having whether or not there has been a storm at all. T & T Roofing South Wales assesses roofs across Cwmbran free and without obligation.