If you own a 1930s red-brick semi in Drumcondra, Cabra or Marino, a pre-winter roof inspection should focus on five things: hip tile bedding, valley lead condition, chimney flashings, slipped Bangor Blue slates, and gutter falls. Do it before the November Atlantic gales. Book a proper roof inspection by mid-October, or call us on 01 2657795 for a fixed-price quote.
That's the short answer. Now here's what a Dublin roofer actually looks for on these houses, and why the interwar building stock in D9 and D3 needs a different eye than a 1990s estate in Lucan.
The housing typology across Drumcondra, Cabra, Marino, Fairview and parts of Glasnevin is remarkably consistent. Most of it went up between 1927 and 1939 under Dublin Corporation's post-independence housing drive — Marino was the first major scheme (Marino Crescent and the Griffith Avenue estates), followed by the Cabra and Drumcondra Corporation builds. Red-brick or roughcast walls, hipped roofs, clay ridge and hip tiles bedded in sand-cement mortar, and Bangor Blue Welsh slate as the standard covering.
Ninety-odd years on, that original spec is at the end of its service life. Bangor Blue slate itself is famously durable — 100 to 125 years is realistic — but the fixings, the mortar bedding, and especially the lead flashings rarely make it that far without intervention. In our own log of Dublin inspections over the past three years, roughly 7 out of 10 unrestored 1930s semis showed at least one of: nail sickness, hip tile slippage, or perished valley lead. Any one of those will let water in over a wet winter.
Dublin gets around 730–760 mm of rain a year, less than Cork or Galway, but our winter weather is defined by short, sharp Atlantic lows rolling in from the west and southwest. November through February is when things break. A gable-end hip that's been quietly loose since summer will let go in a 90 km/h gust off the Irish Sea.
The hipped roof is the defining feature of these houses, and the hip tiles — half-round or angular clay units running from ridge down to eaves — are almost always bedded in a sand-cement mortar from the original build. That mortar is now 85–95 years old.
What to look for:
Modern best practice under I.S. EN 1304 and the NSAI code is mechanical fixing — hip tiles screwed or clipped, not just bedded. Rebedding a full hip run on a standard semi in Cabra runs an indicative €450–€850 per hip (2025 rates, confirm on site), and most houses have two.
Where the main roof meets a rear return or a projecting bay, you'll find a lead valley. On a 1930s semi, that lead is typically code 4 or code 5, and it's been expanding and contracting through 90 Dublin winters. It cracks along the centre line, splits at the laps, and eventually pinholes.
Get up close and check for:
Renewal should be code 6 lead minimum, dressed properly with welted edges. Budget indicatively €650–€1,200 per valley including scaffold access.
Almost every 1930s semi has at least one chimney stack, often two. The lead soakers, step flashings and back gutter around that stack are the single most common leak point we find. Original flashings were often code 3 lead — under-specified even for the 1930s — and the mortar fillets that many well-meaning owners have applied over the decades crack within two winters.
Check for:
A full stack re-flash with code 4/5 lead runs indicatively €550–€950 per stack. If the brickwork needs repointing at the same time, add €300–€600.
Bangor Blue is Welsh slate from the Penrhyn quarry — thin, dense, and dark blue-grey. The slates themselves usually outlast the copper or iron nails holding them up. When nails corrode, slates slip. This is nail sickness, and it's the number one reason a 1930s Dublin roof needs attention.
Signs of nail sickness:
If you're losing more than 5–10 slates a year across the roof, you're past patch-repair territory and into strip-and-relay. A full re-roof on a standard 3-bed semi in Marino using reclaimed Bangor Blue is indicative €14,000–€22,000; using new Spanish slate as a substitute brings it to €11,000–€16,000. Get exact figures with a fixed-price quote.
Have a look at examples of our completed slate work to see what a proper Bangor Blue relay looks like.
The original cast-iron half-round gutters on these houses are mostly gone, replaced piecemeal with uPVC over the years. Check that:
Blocked gutters are what turn a small flashing defect into a saturated bedroom ceiling. Clear them in October, full stop.
Book the inspection between mid-September and mid-October. That gives you time to schedule remedial work before the weather closes in. Trying to get scaffold up and lead work done in a wet, windy January is miserable, more expensive, and often has to wait for a dry window anyway.
An inspection on a standard semi takes 45–75 minutes, includes a scaffold-tower or ladder-and-harness roof-level survey (not just binoculars from the garden), photographs of every defect, and a written report. Indicative cost €150–€250, often credited against any remedial work booked. Confirm current rates when booking.
If you want to sanity-check likely repair budgets before you call, the roofing cost calculator gives ballpark figures for the common jobs.
Drumcondra (D9): The stretches along Hollybank Road, Ferguson Road and the roads off Grace Park have particularly tall stacks and steep roof pitches — factor in scaffold cost. Mature trees mean valley debris is a bigger issue here than elsewhere.
Cabra (D7): The Corporation estates around Fassaugh Avenue and Ratoath Road were built to a tighter budget than Marino — original lead work was lighter gauge, so flashings tend to fail earlier. Chimney stack repointing is very common.
Marino (D3): The Marino Crescent and Griffith Avenue houses are architecturally protected in parts — check with Dublin City Council before any material change (e.g. moving from Bangor Blue to a concrete tile substitute is a non-runner on protected terraces).
For homeowners on the southside dealing with similar interwar stock, our South Dublin roofing team covers the equivalent typology in Terenure, Rathmines and Harold's Cross.
If your roof hasn't been properly looked at in the last five years — and especially if the house has been in the family since your parents' or grandparents' time — get it done now. Call 01 2657795 or request a free pre-winter inspection quote through our contact page and we'll be out within the week.
Every 3–5 years for a roof in good condition, annually once it's over 80 years old or if you've had previous slippage. After any storm with winds above 90 km/h, do a visual check from the ground.
Yes, if they're sound. A slater will sort salvageable slates from cracked ones — typically 60–75% are reusable on a 1930s roof. Reclaimed Bangor Blue costs €3–€5 per slate versus €1.50–€2.50 for new Spanish alternatives, but the visual match is worth it on protected streets in Marino.
Storm damage clusters — you'll lose 5–15 slates from one area in one event. Nail sickness is random and gradual — one slate here, two there, over months. Nail sickness means the whole roof is failing; storm damage is a repair job.
Not usually, as long as you're using the same material (slate for slate). If the house is on a protected structure list or in an Architectural Conservation Area — parts of Marino Crescent are — check with Dublin City Council Planning first. Changing to concrete tiles almost always needs consent.
Not directly for roofing, but if you're doing attic insulation as part of the works, the SEAI Better Energy Homes scheme offers €1,500 for attic insulation (2025 rates). Roof repair itself is not grant-aided. Confirm current SEAI eligibility before applying.
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