Haverhill Roofers provides commercial roofing in Saffron Walden, covering repairs and full replacements on flat roofs, profiled metal sheet roofs, box gutters and rooflights on business and agricultural premises.
Call any time. Calls are answered day and night and passed straight to our roofers.
Commercial roofing projects on business premises, industrial units and farm buildings involve more stages than a domestic roof replacement. There is more roof to survey, more planning around access, more consideration of how to keep your operation running during the work, and more decisions to make along the way. This page walks through each stage of a typical commercial roofing job near Saffron Walden so you know what a properly run project looks like before anyone sets foot on your roof.
A commercial roof survey is not a quick look from the ground with a pair of binoculars. To give you an accurate picture of what is happening and what needs doing, the roof has to be physically accessed and inspected at close range. This means a safe means of access, whether scaffolding, a mobile elevated work platform or roof ladders, depending on the roof type and height.
During the survey, the condition of the membrane or sheeting is checked across the whole surface, not just the area above the obvious leak. Upstands, abutments, flashings, verge details and penetrations are all inspected individually because these are the areas where failures most commonly occur. Box gutters and outlets are checked for blockage, silting and liner condition. Any rooflights are assessed for condition and weather-tightness.
The deck or substrate below the membrane is probed where there is any sign of saturation. A wet deck that looks intact from above is a hidden problem; if it is not identified now, it becomes an expensive surprise once work starts. On metal sheet roofs, fixings and sheet laps are checked for corrosion and movement.
At the end of the survey you should receive a clear written report covering what was found, what requires immediate attention, what can be managed in the short term, and what the options are. A survey that results only in a verbal summary and a single-line quote is not sufficient for a commercial property.
Once the survey findings are clear, the scope of work is agreed before anything else happens. This should specify the system to be used (membrane type, sheet specification, or lining material), the area being covered, how penetrations and upstands will be treated, what access method will be used and whether the existing deck needs any remedial work before the new covering goes on.
On a commercial building, the timing of the work matters. A project that can only be carried out during a business closure, or that needs to be phased to keep part of the building operational, needs to be planned at this stage. Work on flat roofs should ideally be scheduled in drier months, though emergency repairs cannot always wait. Profiled metal sheet work can proceed in most conditions as long as fixings can be installed safely.
Any provisional items, work that is priced subject to what is found when the old material comes off, should be identified clearly. Deck repairs are the most common provisional item on flat roof replacements. If the deck is in worse condition than the survey suggested, the scope and cost will change. You need to know in advance how that will be handled and how decisions will be communicated to you before additional work proceeds.
Safe access to a commercial roof is not an optional extra. Working at height regulations apply to all commercial roofing work, and the access method has to be appropriate for the building height, roof type and duration of the project. For most flat-roofed commercial and industrial buildings, a mobile elevated work platform is the most practical access method. For larger projects or those where the perimeter needs to be fully accessible, scaffolding is erected first.
Protecting the building interior and the areas below the roof from debris, dust and weather ingress while the old covering is stripped is part of the job. On occupied buildings, this means working in sections where possible, so that the building is not left open to weather overnight. Materials and waste are managed on the roof rather than thrown directly to ground level wherever the building layout allows.
Stripping a flat roof means removing the existing membrane and, if it is in poor condition, the insulation and perhaps the deck boards below. Built-up felt roofs on commercial buildings often have two or three layers of felt that have been overlaid over the years; stripping back to the deck reveals the true condition of the substrate.
On profiled metal sheet roofs, stripping usually means removing the existing sheets and liner, checking and treating the purlins below for any corrosion, and replacing any rotten or damaged insulation before the new sheets go on. Fixings into the purlins are drilled out and fresh fixings go into clean metal at the original or adjacent positions.
All stripped material is loaded and removed from site. The weight of wet felt and old insulation adds up quickly on a large commercial roof, and the removal and disposal of this material is part of a properly run job. If a quote does not include waste disposal, ask why.
Before any new membrane or sheeting goes on, the substrate has to be sound, dry and clean. On flat roofs, any damaged deck boards are replaced, loose boards are re-fixed, and the surface is swept and dried before the first layer of insulation or membrane is applied. If there are areas of rot or structural damage, these are dealt with now.
Falls are checked at this stage. If the original falls were inadequate, tapered insulation boards can be used to create the correct gradient without altering the roof structure. This is a more expensive option than flat boarding, but it solves ponding problems permanently rather than leaving them for the next roofer to find.
Membrane installation on a commercial flat roof proceeds from the lowest point upward. On a felt system, each layer is bonded to the one below using a gas torch or cold adhesive, with laps running in the direction of water flow so that water never has to travel against a lap edge. On an EPDM system, the membrane is rolled out in as few pieces as possible, bonded at the perimeter and at any joins, and then edge-trimmed and detailed at all upstands, abutments and penetrations.
Penetration details are formed individually using preformed collars or cut-and-bonded patches, depending on the system. This is the stage where the quality of the installation is determined; a membrane that is perfectly laid across the main field but poorly detailed at pipe penetrations or upstands will leak there within a few years.
On profiled metal sheet roofs, new sheets are laid to the correct lap and fixed at the specified centres, with sealing tape or mastic at the laps as required by the system. Ridge, verge, eaves and gutter fixings are all fitted to the correct details. New rooflights are fitted at this stage, bedded and sealed correctly into the sheet line.
Box gutters are relined or replaced after the main roof covering is complete on a flat roof project, or alongside the sheet installation on a metal roof. On a felt or EPDM flat roof, the box gutter lining is taken up and integrated with the main membrane at the internal junction so there is no step or gap for water to find. The outlets are checked for size against the roof area; where drainage is insufficient, additional outlets are added at this stage.
Before leaving site, the finished roof should be walked in full. Every penetration, upstand, edge, gutter outlet and rooflight should be checked visually. Any debris on the roof surface is cleared, because debris left on a flat roof will eventually block outlets and cause ponding.
The site below is cleared of all materials, packaging and waste. Access equipment is struck and removed. You should be left with a clean site and a clear understanding of what was done and what, if anything, needs monitoring going forward.
If you have a commercial roof project near Saffron Walden and want to understand what the job involves before committing to anything, call us to arrange a survey and we will walk you through exactly what we find and what we recommend.
No obligation · We'll call you to arrange a free visit
Call any time. Calls are answered day and night and passed straight to our roofers.
