If you have never had a flat roof replaced or repaired in Attleborough before, knowing exactly what the job involves helps you plan and ask the right questions.
Call any time. Calls are answered day and night and passed straight to our roofers.
Flat roofing work can feel opaque if you have never been through it. Roofers arrive, there is noise and activity, and then it is done - but what actually happened? We think homeowners deserve a clear account of the process. Below is a step-by-step explanation of how a typical flat roof replacement is carried out, from the first visit to the final tidy-up.
We work on extensions, garages, and outbuildings in and around Attleborough. The process described here applies to a full replacement using either torch-on felt or EPDM rubber membrane - the two systems we install.
Before any quote is given, the roof should be inspected properly. This means getting on the roof and checking the membrane condition across the whole surface, the perimeter trims and edge details, all upstands where the roof meets walls, and the outlets or drainage points. If any areas feel soft or spongy underfoot, those spots need particular attention - soft decking means moisture has got into the boards beneath the membrane.
The inspection should also check the fall. Flat roofs are not truly flat - they need a minimum fall of around 1:80 (roughly 1.25cm per metre run) to drain reliably. If water is ponding persistently, the fall may be inadequate or the decking may have deflected. This affects how the job needs to be specified.
A good inspection takes time. If a roofer quotes from the ground or from a quick glance over the edge, that is a sign that the quote may not reflect what the job actually involves.
Once the inspection is complete, you should receive a clear written quote that specifies what is being done - not just a price. The quote should state the system being installed (felt type and specification, or EPDM), what happens with the existing membrane, whether the decking will be checked and what happens if boards need replacing, how upstands and flashings will be formed, and what drainage provision is included.
Decking replacement is a point worth discussing specifically. The condition of the boards is not always clear until the old membrane is stripped - boards that look acceptable can be found to be delaminated or softened once the covering comes off. A responsible quote will explain how this is handled if it arises, so there are no surprises on the day.
Before work starts, the area below and around the roof needs protecting. On an extension or garage, this means protecting any paving, plants, or other surfaces from debris and stripped material. Ladders and any necessary scaffolding or tower are set up to give safe access to the roof - access requirements vary depending on the height and configuration of the structure.
Neighbours should be aware that there will be noise, particularly during strip-out. On a typical domestic flat roof this phase is relatively short, but it is worth managing expectations, particularly in terraced or semi-detached situations.
The existing membrane, edge trims, and any loose or damaged insulation are stripped back and removed. On a felt roof this means cutting the felt free, pulling up any chippings, and removing the layers. On a rubber membrane, the sheet is cut and pulled away, with adhesive residue scraped clean where necessary.
Once the membrane is off, the decking can be properly assessed. Any boards that are soft, delaminated, or structurally compromised are cut out and replaced with new OSB or plywood of the correct thickness - typically 18mm or 22mm. It is important that the decking is sound and level before any new membrane goes down. Replacing a few boards at this stage is far less costly than dealing with a failed installation later.
If the roof is being upgraded to a warm-deck specification - which is worth considering on any full replacement - rigid insulation board goes down on top of the clean decking at this stage. The insulation is laid in a tight, overlapping pattern to minimise cold bridging. The thickness used affects both thermal performance and the final roof height, which may need checking against doors, sills, or other adjacent elements.
On a cold-deck roof (where insulation sits between the joists rather than above the deck), this step is skipped - but it is worth knowing that cold-deck configurations carry a higher risk of interstitial condensation within the roof structure over time.
This is the core of the job and where the quality of the installation is determined. The process differs between felt and EPDM.
For torch-on felt, the base layer is applied first and bonded to the deck with heat from a propane torch. The cap sheet follows, torch-welded on top, with all laps and joints carefully sealed. Upstands are formed by cutting and welding the felt up the vertical face of any adjoining wall, to a height of at least 150mm above the finished roof level. Edge trims are fitted and the felt is turned over them to create a watertight perimeter.
For EPDM, the sheet is rolled out across the clean, primed deck and positioned carefully before bonding begins. Contact adhesive is applied to both the membrane and the deck in sections, allowed to flash off, and then the membrane is pressed firmly into place and rolled to ensure full contact. Seam tape is used at any joins, and pre-formed corners or cut-and-fold detailing handles the upstands. Edge trim is mechanically fixed and the membrane turned over it and bonded down.
In both cases, flashings to adjoining walls - typically lead or aluminium - are dressed in and secured, with sealant at the top edge if the flashing is not chased into the mortar joint. These perimeter details are where flat roofs most often fail, and they deserve as much care as the field of the roof itself.
Drainage outlets are cleaned, re-seated, or replaced as required and the membrane is carefully formed around them. Any roof lights, vents, or pipe penetrations are addressed with pre-formed collars or hand-cut details bonded to the membrane. The roofer should check the finished roof for any areas of poor adhesion, gaps at upstands, or bridging at corners before leaving the roof.
The fall is checked visually - water should run cleanly to the outlet without pooling anywhere on the finished surface.
All stripped material, old felt, chippings, off-cuts and packaging should be removed from site and disposed of properly. Skips or a van load - the method varies - but the customer should not be left to deal with waste. Paving, planting, and any surfaces that were covered during the work should be checked and cleared.
At this point you should be able to walk around and inspect the finished roof. Ask to see the upstands, edge trims, and outlets up close if access allows. A roofer confident in their work will have no issue with that.
If your flat roof on an extension, garage, or outbuilding near Attleborough needs replacing or repairing, call us to arrange an inspection. We will walk you through what the roof needs and provide a clear written quote before any work starts.
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Call any time. Calls are answered day and night and passed straight to our roofers.
