Here is exactly what happens when Newmarket Roofers carry out a flat roofing job in Haverhill, from the first look at your roof through to clearing away at the end.
Every flat roofing job starts with a proper look at what is there. We inspect the whole roof surface, not just the area where a leak has appeared. Water travels, so the entry point is frequently some distance from the wet patch on the ceiling below. We check the membrane surface, the edge details, the upstands where the roof meets any walls, the condition of flashings and the state of the outlet or drainage channel.
We also check, where access allows, whether the deck beneath the membrane is sound. On a felt roof this usually means pressing firmly at the surface and noting any give - soft spots indicate moisture in the build-up and potential rot in the boarding or joists below. If there is any doubt about the deck we will say so at this stage, because hidden rot changes the scope and cost of the job.
At the end of the inspection we tell you what we have found and what the options are. For some roofs, a targeted repair is the right answer. For others - particularly older felt roofs that are cracking across the surface rather than failing at one point - a full replacement is the more practical choice. We will explain the reasoning rather than just giving you a price.
Once you have decided how to proceed, we agree the scope of work. For a full replacement this includes: the method of stripping the old covering, whether any decking needs to be replaced before the new membrane goes on, the specification of the new system (typically EPDM rubber for most domestic roofs), and how the edge, upstand and outlet details will be handled.
Access is planned at this stage. Most single-storey flat roofs - extensions, garages, outbuildings - are accessible from a ladder without scaffolding, but we assess each job individually. Where the roof is above a conservatory, there are vulnerable surfaces below, or the work area is tight, we plan accordingly before starting.
We also pick a weather window. EPDM bonding adhesive needs dry conditions to cure properly and will not perform correctly if applied to a damp surface. We do not start a flat roof installation in wet weather. This is not inconvenient fussiness - it is the reason the installation works.
On a full replacement, the existing covering comes off first. For a felt roof this means cutting back and peeling the felt layers away from the deck. Torch-on felt can be stubborn and requires care to avoid damaging the boarding beneath. Mineral felt is messy work - it comes away in sections and the debris needs to be bagged and removed from the site as the job progresses.
Stripping is the point at which hidden problems become visible. It is common to find areas of decking that have absorbed moisture and begun to delaminate or soften - this is particularly true at edges and around the outlet where water sits longest. Any boarding that is soft, spongy or visibly delaminated has to come out. Leaving compromised decking in place and covering it with a new membrane is not a repair - it is postponing a larger problem.
The joists beneath are inspected at the same time. Joist damage from long-term water ingress is less common but does occur, particularly on roofs where a leak has been present for several years without being addressed. If joists need attention, we deal with that before anything else goes back on top.
Any boarding that was found to be compromised during stripping is replaced at this stage. For domestic flat roofs we use exterior-grade plywood, typically 18mm or 22mm thickness. Plywood is dimensionally stable, holds fasteners well and does not swell as unpredictably as OSB when exposed to moisture during the installation period.
New boards are fixed securely to the joists with screws rather than nails - a screw-fixed deck does not develop the squeaks and raised fixings that nail-fixed boarding can produce as the timber moves seasonally. All board edges are staggered so that no joint runs continuously across the deck, which prevents a single line of weakness across the surface.
On a new installation or a full replacement, insulation goes in at this stage. We build warm roofs as standard for new work - rigid insulation board is fitted on top of the deck, beneath the membrane. This puts all the insulation on the warm side of the structure, eliminating the risk of condensation forming in the roof build-up, which is the cause of many cold roof failures.
The insulation boards are cut to fit cleanly, with no gaps at edges, and tapered boards can be used where additional fall is needed to achieve the correct drainage gradient. A minimum fall of 1 in 80 across the whole surface is the target - anything less and water begins to pond.
EPDM rubber membrane is supplied in large rolls and cut to size on site. For many domestic roofs, the main field area can be covered in a single piece with no joins across the surface at all. This is one of the significant practical advantages of EPDM over multi-layer felt systems.
The adhesive is applied to both the insulation surface and the underside of the membrane and allowed to become tacky before the two surfaces are brought together. The membrane is then rolled out carefully across the roof, smoothed down from the centre outwards to prevent air pockets, and pressed firmly into the adhesive. Any remaining bubbles are worked out before the adhesive sets.
The membrane is taken up the upstands - the vertical faces where the roof meets walls or parapets - and bonded there too. EPDM upstand strips or purpose-cut pieces of the main membrane are used for this, bonded with the same system adhesive and sealed at the top with a compatible cover strip or mechanical fixing. This is one of the most critical details: an upstand that lifts even partially will let water in behind the membrane.
The perimeter of the roof is finished with aluminium or EPDM-compatible edge trim, mechanically fixed to the fascia board and bonded to the membrane. This trim holds the membrane edge down, protects it from wind uplift and gives the roof a neat finish at the fascia line.
Where the roof meets a masonry wall, lead or EPDM flashing seals the joint. Lead is dressed into a chase cut in the mortar joint and wedged in place before being sealed with compatible pointing. This is not a detail that benefits from shortcuts: flashing that is surface-bedded with mastic rather than properly chased into the wall will lift within a few years as the mastic deteriorates.
The outlet is fitted or reinstated last, bonded through the membrane so that water runs into the outlet from the surface rather than under the membrane edge. Outlet position relative to the low point of the roof fall matters - the outlet needs to be at or close to the lowest point, not on a high side.
Before we leave, we walk the finished roof and check every join, upstand bond, edge trim fixing and flashing. We check the outlet is clear and that water runs freely toward it. Any debris from the job - old felt, offcuts, packaging - is cleared from the site.
We also point out anything we noticed during the job that is outside the scope of the flat roof itself - guttering condition, fascia board state, any issues visible on the adjoining pitched roof if there is one. We will not present you with an unexpected bill for extras, but we will tell you if something else warrants attention so you can decide.
A flat roof repair on a small area - sealing a lifted flashing or patching an isolated split - typically costs £150 to £400. A full strip and replacement on a domestic garage or single-storey extension, including EPDM membrane and any decking repairs, generally runs from £900 to £2,500. Larger roofs, difficult access, multiple penetrations or significant timber repairs will push costs higher.
To get an accurate figure for your roof, call us to arrange an inspection. A quote without a proper look at the roof is not worth the paper it is written on.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
