If you are having a flat roof replaced or repaired in Saffron Walden, here is exactly what the job involves from the moment we arrive to the moment we leave your property.
Call any time. Calls are answered day and night and passed straight to our roofers.
A lot of homeowners get a price for flat roofing work without really knowing what they are paying for. Understanding how a flat roof job should be carried out helps you judge whether a roofer is doing the work properly - and spot if corners are being cut. This page walks through the process step by step, from the initial inspection through to clearing up at the end.
Haverhill Roofers carries out flat roof replacements and repairs on garages, extensions and dormers for homeowners in Saffron Walden and the surrounding area.
Before any work is priced or planned, the roof needs a proper look. That means getting up on the roof itself, not just looking at it from the ground. A ground-level inspection tells you very little about the condition of a flat roof membrane, the state of the deck underneath, or how the upstand and flashing details are holding up.
During the inspection we are checking several things at once. The membrane is examined for blistering, cracking, open laps, splits at upstands and general deterioration. The deck is tested underfoot for any soft or spongy areas that indicate moisture in the timber. Drainage outlets and gutters are checked for blockages. Flashings and any lead work at wall abutments are inspected for cracks, corrosion or mortar failures.
If the roof is a replacement rather than a repair, we also check the fall. A flat roof should have a minimum fall of 1:80 to drain correctly. If the existing roof is flat with no fall, or if the fall has dropped over time because the deck has settled, that needs to be addressed when the new covering goes on.
For a full replacement, the old membrane is stripped back completely. This is not optional. Laying new felt or EPDM rubber over an existing covering hides any problems beneath and adds unnecessary weight to the structure. A proper job always starts with a clean deck.
Once the old felt is stripped, the deck boards are inspected individually. Any boards that are rotten, delaminated or have visible water damage are removed and replaced with new OSB or plywood cut to match. This is the stage where the true extent of any water damage becomes apparent - and why some jobs cost more than the original estimate anticipated. If a deck looked sound from the outside but shows rot once the felt is off, the right thing to do is replace the affected sections rather than cover them over.
Skirtings, abutment timbers and any existing insulation are also checked and replaced where necessary before the new covering goes down.
With a clean, sound deck in place, any fall corrections are made. Tapered insulation boards are one option for improving drainage without altering the roof structure below. Where a roof drains to a gutter, the outlet position and gutter condition are confirmed before the membrane goes on - replacing a gutter hidden under a new roof covering is a much bigger job than replacing it beforehand.
For warm roof systems, rigid insulation boards are fixed to the deck at this stage. A warm roof puts the insulation above the deck rather than between the joists, which keeps the deck warm, prevents condensation forming within the structure and improves the thermal performance of the room below. On an extension or habitable dormer, this is generally the right approach.
The method here depends on the material being used.
Torch-on felt is applied in layers using a gas torch to melt the bitumen underside and bond it to the substrate. The first layer is a base sheet, which is bonded to the deck. A second and sometimes third layer follows, with each layer lapped and bonded over the one below. The cap sheet on top has a mineral surface to reflect UV and provide a degree of surface protection. Upstands at walls are dressed up and bonded properly, with lead or aluminium flashing taken over the top and tucked into the mortar joint above.
EPDM rubber is typically cut from a roll to cover the roof in as few pieces as possible - ideally one continuous sheet for a standard garage or small extension. The sheet is laid out, allowed to relax, then bonded to the deck using a contact adhesive applied to both surfaces. Edges and upstands are trimmed and sealed with compatible EPDM tape and edge trim. Seams, where they exist, are bonded with specialist EPDM seam tape, not standard mastic or lap sealant.
In both cases, the detail work at upstands, penetrations, rooflights and drainage outlets is where the quality of a flat roofing job is really measured. Getting the field membrane down correctly is straightforward; the details are where shortcuts show up as leaks within a few years.
Where the flat roof meets a wall, chimney or another roof element, a flashing is needed to seal the junction. Lead is the traditional and still the best material for this - it is soft enough to be worked into shape, durable and compatible with both felt and EPDM systems.
A lead flashing is cut to size, dressed into the brick or mortar joint using a chase cut into the masonry, and pointed in with fresh mortar or lead wedges. The lower edge is dressed down over the membrane upstand. A common failure on older roofs is that the flashing has been sealed with mastic rather than properly chased in. Mastic cracks and shrinks, and it is only a matter of time before water gets in behind it.
Once the membrane and flashings are complete, the whole roof surface is walked and checked. Every upstand, every lap, every flashing tail and every drainage point is looked at before we come off the roof. If there is any doubt about a detail, it is addressed at this stage rather than after the scaffolding or ladders are down.
Where there is a rooflight or internal drain, water flow is tested to confirm drainage is working as it should. Gutters are cleared of any debris from the stripping work.
Old felt, broken deck boards, off-cuts and packaging are loaded and taken away. Scaffolding boards or ladder mitts are removed. If a garden has been used as a working area, it is left tidy. A good roofer clears up as they go and leaves the property as they found it.
A standard single-garage flat roof replacement typically takes one to two days. An extension roof may take two to three days depending on its size, the complexity of the drainage details and whether significant deck repairs are needed. Jobs that seemed straightforward but reveal substantial deck damage can take longer - this is one reason why getting a proper inspection before work starts matters.
Any roofer who cannot answer these clearly is worth being cautious about.
Call Haverhill Roofers to arrange an inspection of your flat roof in Saffron Walden or the surrounding villages. We will walk you through what we find and give you a clear price for the work before anything starts.
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Call any time. Calls are answered day and night and passed straight to our roofers.
