Thetford Roofers handles flat roof replacements and repairs for homeowners in Attleborough, taking each job from first inspection through to a clean, finished site.
If you have never had a flat roof replaced, it can be hard to know what to expect from the process. Understanding each stage helps you ask the right questions, avoid surprises, and judge whether a roofer is doing the job properly. Here is how the work runs from start to finish.
Before any price is agreed, the roof needs to be looked at properly. A good inspection goes beyond standing in the garden and squinting upwards. A roofer should get onto the roof surface, check the condition of the covering, probe any soft or spongy areas that might indicate wet decking beneath, look at how the perimeter edges are dressed, and check that outlets and drainage points are clear and functional.
Wall junctions and upstands, the areas where the roof surface meets a vertical wall or parapet, deserve particular attention. These are the points where most flat roofs fail first, because the seal has to cope with thermal movement throughout the year and any weakness in the flashing or upstand detail will eventually let water in.
Standing water is worth identifying early. A roof that holds water for more than 48 hours after rain has either a drainage problem or an insufficient fall. This may affect which repair or replacement option is appropriate, and it needs to be addressed as part of the job rather than left for later.
At the end of the inspection, you should get a clear explanation of what has been found and what the options are. If a roofer will not give you that conversation before taking a deposit, find someone else.
Once the inspection is complete, the scope of work can be set out. For a straightforward replacement, this covers: stripping the existing covering, checking and replacing any damaged decking, installing the new membrane system, redressing flashings and perimeter edges, and clearing up on completion.
If the existing deck is suspected to be wet or rotten, the price should reflect the possibility of additional decking replacement, or there should be a clear agreement about how any extra cost will be handled if problems are found once stripping begins. Make sure you know what is included before work starts.
The system to be installed should also be specified at this point, whether that is a torch-on felt, EPDM rubber membrane, or another option suited to your roof. Vague descriptions like "high-quality felt" are not good enough. Ask for the product and system to be named.
Work begins with stripping off the old covering. On a felt roof this means removing all layers of felt down to the deck, taking away the debris, and leaving the surface clean ready for inspection. On older roofs it is common to find that the timber decking has taken on moisture, either from a slow leak or from condensation within a cold-deck build-up.
Rotten or wet boarding must be replaced before the new covering goes on. Installing a new membrane over compromised decking is one of the most common reasons a flat roof fails prematurely. Any soft boards should be cut out and replaced with exterior-grade plywood of the correct thickness, properly fixed to the joists.
This stage is also the right time to look at the falls. A flat roof needs a minimum gradient of around 1 in 80 to drain properly. If the original deck was built with an insufficient fall, tapered insulation boards can be used to create the correct drainage angle as part of the build-up, rather than relying on the covering to cope with water that has nowhere to go.
With the deck exposed, inspected and any damaged sections replaced, preparation work begins before the new membrane is applied. For felt systems this typically involves priming the deck surface. For EPDM, the deck needs to be clean, dry and even, with all fixings set flush so there are no raised points that could cause stress in the membrane.
Insulation is usually installed at this stage if a warm-deck system is specified. Warm-deck construction places the insulation above the deck and below the waterproof membrane, which is the modern approach and avoids the condensation risks associated with older cold-deck roofs. If your property has an older flat roof with little or no insulation, a replacement is a practical opportunity to upgrade the thermal performance at the same time.
The installation method depends on the system chosen. Torch-on felt is applied using a gas torch to bond each layer to the one below, working from the lowest point of the roof upward so laps shed water rather than catching it. Joints between sheets need to be fully bonded, not just tacked at the edges.
EPDM rubber is typically adhered in large single sheets, bonded to the deck with a contact adhesive. Because the sheets are wide, there are far fewer joints than in a felt system. All perimeter edges are dressed down over a timber upstand or trim, and any penetrations such as pipes or vents are sealed with purpose-made collars or flashing tape rather than improvised patches.
Regardless of system, upstands where the membrane meets a wall should turn up at least 150mm and be dressed under a cover flashing fixed into the masonry. A membrane that is only taken to the base of a wall and relies on mastic alone will not stay watertight for long.
Lead or aluminium flashings are cut, fitted and dressed into the mortar joints or fixed into the masonry at wall junctions. This is detail work that takes time to do properly. Poorly fitted flashings are the single most common cause of callbacks on new flat roofs, so this stage should not be rushed.
Perimeter drip edges and fascia trims are fitted to ensure water is carried clear of the building at the roof edge rather than running back behind the fascia boards. Outlets and any guttering connections are checked for alignment with the fall of the roof so water clears quickly after rain.
Once the covering, flashings and edgework are complete, the finished roof should be walked over and checked before the site is left. Any laps or joints that have not fully bonded, any edge detail that is lifting, or any flashing that is not fully seated needs to be addressed at this point rather than left to become a problem after the first rain.
All stripped material, old felt, timber offcuts and packaging should be removed from site. Gutters should be cleared of any debris that has fallen into them during the work. The roof surface itself should be left clean.
If you see any of the following, it is worth having the roof inspected before a minor problem becomes a major one:
We work in Attleborough and travel to neighbouring towns and villages across the area, including Thetford, Brandon, and nearby communities. If you want to know whether we cover your address, give us a call.
To book a flat roof inspection and get clear advice on what your roof needs, call Thetford Roofers and ask to arrange a roof survey.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
