Commercial Roofing in Mildenhall - Materials and Options Explained

Expert Commercial Roofing
in Mildenhall

Choosing the Right Commercial Roofing Material

What follows is a straightforward breakdown of the main options available for commercial roofs, with the genuine advantages and drawbacks of each.

Built-Up Felt (BUR)

Built-up felt roofing - sometimes called built-up bitumen or BUR - has been used on flat and low-pitch commercial roofs for decades. It consists of multiple layers of bitumen-impregnated felt, bonded together with hot or cold applied bitumen, with a mineral or chipping finish on the top layer.

Advantages:

• Lower upfront material cost than single-ply or metal alternatives.
• Widely understood and straightforward to repair if sections are damaged.
• The mineral or chipping surface provides some protection against UV degradation and foot traffic.
• Suitable for irregular or awkward roof shapes where sheet materials are harder to fit.

Drawbacks:

• Shorter lifespan than modern alternatives - typically 15 to 25 years, less if the falls are poor or maintenance has been neglected.
• The seams between sheets are a persistent weak point; they can lift or crack as the felt ages.
• Heavy to apply, requiring a strong deck substrate - if the deck needs replacement, costs rise quickly.
• Blistering is common if moisture is trapped during installation or if there is no vapour control layer.

Built-up felt is a reasonable choice for smaller commercial roofs where budget is tight and the building is not expected to be held long-term. On a large warehouse or a building where disruption during future works would be costly, the shorter lifespan is a significant drawback.

EPDM Rubber Membrane

EPDM (ethylene propylene diene monomer) is a single-layer rubber membrane used extensively on commercial flat roofs. It is available in large sheet widths, which means fewer seams than built-up felt - and seams are where most flat roof leaks originate.

Advantages:

• Fewer seams than multi-layer felt systems, reducing the most common failure point.
• Good resistance to temperature extremes - it stays flexible in cold weather and does not soften excessively in summer heat.
• Lightweight compared to built-up felt, placing less load on the roof structure.
• Can be fully adhered, mechanically fixed or ballasted (held down with gravel), giving flexibility on different deck types.
• Typically a longer service life than built-up felt when correctly installed - 25 to 35 years is realistic.

Drawbacks:

• Puncture resistance is lower than some other single-ply options; roofs with regular maintenance foot traffic need protection boards laid as walkways.
• The black surface absorbs heat, which can increase internal temperatures in summer - relevant for offices or refrigerated storage.
• Repairs require compatible EPDM tape or adhesive; using the wrong product leads to adhesion failure.
• Cost is higher than felt for the initial installation, though the longer lifespan often makes it better value over time.

Single-Ply Membrane (PVC and TPO)

PVC and TPO (thermoplastic polyolefin) are the other main single-ply options used on commercial flat and low-pitch roofs. They are hot-air welded at the seams, creating a continuous, bonded joint that is generally stronger than an adhesive seam.

Advantages:

• Hot-air welded seams are among the most reliable joint methods available on flat roofing.
• Available in light colours - white and light grey - which reflect sunlight and can reduce solar gain inside the building.
• Good root resistance, making them suitable for green roofs or planted systems if that is a consideration.
• Strong resistance to oils, greases and chemicals - relevant for food production or industrial buildings.

Drawbacks:

• Higher material and installation cost than EPDM or felt.
• PVC can become brittle over time, particularly at seams and edges, if the plasticisers migrate out of the material. Quality varies significantly between manufacturers.
• Requires a skilled installer with the correct hot-air welding equipment; poor welds are a common cause of premature failure on cheaper installations.

Profiled Metal Sheet Roofing

It is applied over a purlin structure and can be installed as single-skin or as insulated composite panels.

Advantages:

• Fast to install over large areas - a significant advantage if business continuity is important and you need the work done quickly.
• Composite panels (steel sheet bonded to an insulation core) provide good thermal performance in a single product, eliminating the need for a separate insulation layer.
• Aluminium does not rust, making it a good choice for coastal or exposed locations.
• Long service life on the structure itself - many steel sheet roofs last 30 to 40 years or more if the coatings and fixings are maintained.

Drawbacks:

• Noise during heavy rain can be considerable on single-skin steel roofs without acoustic insulation.
• The fixings - not the sheets - are usually the first point of failure. Self-drilling screws with neoprene washers need periodic inspection and replacement.
• Over-roofing an existing sheet roof (laying new sheeting over the old) is often more cost-effective than strip-and-replace, but it adds dead load to the structure; a structural check is advisable.
• Colour fading is normal over time; the factory-applied polyester coating on steel sheet typically carries a manufacturer's finish warranty from the sheet manufacturer (separate from any installer workmanship), but the coating will eventually chalk and fade.

Liquid Applied Coatings

Liquid applied systems - typically polyurethane or polyurea-based - are applied as a cold liquid that cures to form a seamless, waterproof membrane. They are often used for refurbishment rather than new build, and are particularly useful on roofs with complex details, multiple penetrations or irregular shapes where sheet materials are difficult to lay without numerous seams.

Advantages:

• Truly seamless once cured - no laps or joints to fail.
• Can be applied over most existing substrates without full strip-off, reducing waste and disruption.
• Good for complex roof geometries and areas with dense pipework or plant.

Drawbacks:

• Highly dependent on installer skill and correct surface preparation - adhesion failure on a poorly prepared substrate is a common cause of problems.
• Application is weather-dependent; cold or damp conditions affect curing and adhesion.
• Cost per square metre is typically higher than sheet membrane systems on simple, open roof areas.

Which Material Should You Choose?

For most flat commercial roofs on a tight budget, built-up felt is the cheapest upfront but costs more over a building's lifetime through shorter replacement cycles. EPDM and single-ply membranes offer a better balance of cost and longevity for most commercial applications. Metal sheeting remains the most practical choice for large-span agricultural and industrial buildings. Liquid coatings are best considered for refurbishment of complex roofs where a full strip is impractical.

If you are unsure which system suits your building in Mildenhall, the best starting point is a proper site survey. We will look at the existing deck condition, falls, drainage, any plant penetrations and how the building is used before making a recommendation. It is worth arranging a survey of your commercial property with a qualified roofing contractor.