A leaking flat roof over a kitchen extension or garage in Tonbridge needs fast, correct diagnosis — not a temporary patch that fails again in six months. We repair all flat roof systems: felt, EPDM rubber and GRP fibreglass. Same-day urgent visits, free written survey, honest advice on whether repair or replacement is the right answer for your roof.
Flat roof repair is a distinct discipline from pitched roofing. The failure modes, materials and correct repair methods differ significantly — we specialise in all three systems.
Three-layer felt is the most common flat roof system on Tonbridge post-war extensions. Splits at lap joints, blistering from trapped moisture, and edge detail failure at upstands and drip edges are the dominant failure patterns. We patch, overlay or strip and relay depending on the extent of failure and the age and condition of the remaining felt.
EPDM tears and punctures are repaired with self-amalgamating EPDM tape and contact adhesive for small areas, or by cutting out and welding in a new section for larger failures. Lap joint failures — where the adhesive bond between EPDM sheets has broken — are repaired by re-bonding with specialist seam adhesive and roller-pressing.
GRP cracks and delamination are repaired by abrading back to sound laminate, applying fibreglass matting and fresh resin, and top-coating with matching GRP topcoat. Correctly done, a GRP repair is invisible and structurally sound. Incorrectly done — applying a surface filler over an active crack — it fails within one season.
A flat roof that ponds water will fail prematurely regardless of membrane type. We address drainage failures by installing additional outlets, clearing blocked outlets, adding tapered insulation to improve falls, or rebalancing a deck that has moved. The drainage solution is included in the repair scope.
Upstand failures — where the membrane has pulled away from a parapet wall or door threshold — are a common leak source on Tonbridge flat roofs. We re-dress, re-bond or install new metal trim depending on the upstand type and membrane system.
Not every flat roof leak requires full replacement. We survey the membrane, deck condition and drainage before recommending. If repair is viable and cost-effective, we say so. If the deck has failed or the membrane is at end of life across the whole surface, we tell you that too.
The majority of flat roof failures we attend in Tonbridge are on rear kitchen extensions built between 1960 and 1990. These properties — across Cage Green, Trench Wood, Higham Wood and the post-war stock throughout the town — were built with three-layer bituminous felt that had a design life of 15–20 years. Many of these roofs are now 30–50 years old and have been re-felted once or twice. A third re-felt over an aged deck is often not viable — the deck boards have absorbed moisture and require replacement before a new membrane will perform correctly.
The Medway Valley humidity in lower Tonbridge has a specific effect on flat roof performance. Properties near Haysden Country Park and the Medway riverside have higher ambient moisture than elevated properties, which accelerates the breakdown of felt membrane adhesion and increases the risk of interstitial condensation in cold-roof constructions. For riverside and valley-floor properties, we recommend warm roof specification on any new flat roof — insulation above the deck eliminates the condensation risk that a cold roof cannot address in this microclimate.
Autumn leaf fall is a specific maintenance trigger for Tonbridge flat roofs near tree cover. Leaves accumulating on flat roof surfaces block outlets and create sustained ponding, which on an already-marginal membrane can be the event that tips a repairable roof into replacement territory. We recommend annual autumn outlet clearing on any flat roof adjacent to deciduous trees — it costs under £100 and extends the membrane life by years.
Typical ranges. Free written quotes on 0173 224 1138.
| Job Type | Typical Cost | Duration |
|---|---|---|
| Small felt repair (split/blister, up to 1m²) | £150–£300 | 2–3 hrs |
| EPDM patch repair (tear/puncture) | £200–£400 | 2–4 hrs |
| GRP crack repair and top-coat | £200–£450 | Half day |
| Outlet clearing + drainage improvement | £80–£200 | 1–2 hrs |
| Upstand re-dress (per linear metre) | £60–£120 | varies |
| Emergency same-day flat roof repair | £250–£600 | Same day |
"Kitchen extension flat roof — same leak for three years, two previous roofers couldn't fix it. These found a drainage issue causing water to track. Fixed the drainage and repaired the membrane. Completely dry since. Should have called them first."
"GRP crack on our garage roof. Properly abraded back, re-glassed, top-coated. You can't find where the repair is. Priced fairly and done in a morning."
"Same-day call for an EPDM tear that was letting in water above the home office. On-site within two hours, repaired properly, no temporary patch nonsense. Very grateful."
If the membrane has isolated failures and the deck is sound, repair is usually viable and cost-effective. If failure is widespread, or the deck has absorbed moisture and softened, replacement is better value. A free survey determines which applies — we won't recommend replacement if repair will do.
Same-day urgent visits for active leaks. Standard survey appointments within 2–3 working days. Call 0173 224 1138.
Repeated leaks in the same location usually indicate a drainage issue — water is tracking to that point. Patching the surface without addressing the drainage cause means the leak recurs. We survey the drainage pattern before recommending a repair approach.
GRP (fibreglass) is seamless, 20–25 year life, best for most domestic extensions. EPDM (rubber) suits larger or more complex shapes, 20 year life. Felt (3-layer torch-on) is cost-effective for simple surfaces, 15–20 year life. We'll advise which is on your roof at inspection.
Simple patch repairs start from £150. Emergency same-day repairs from £250. Free survey and written quote on all jobs. Call 0173 224 1138.
Blocked outlets causing standing water, followed by upstand de-bonding where membrane has pulled from the parapet or door threshold. We check drainage pattern before recommending any repair.
For isolated defects on a sound deck: yes — patch repairs typically £150–£450. Where deck has absorbed moisture or membrane failure is widespread, replacement (£900–£2,500 for a kitchen extension) is better value over 20 years.
Free inspection, written quote, no obligation.
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