Covering Cambridge and the surrounding villages

New Roof or Roof Coating: What's the Difference?

14 September 2026 Cambridge Fencers

Why Cambridge Homeowners Ask This Question

If your roof is looking tired, leaking around flashings, or losing granules from its felt surface, you face a straightforward choice: strip it back and fit a new roof, or apply a coating over what's already there. Both options have genuine uses, but they are not interchangeable, and choosing the wrong one can cost you significantly more in the long run.

Cambridge's climate makes this decision particularly important. The city sits in one of the driest parts of England, but winter frosts are sharp and prolonged, and flat roofs on Victorian terraces, post-war semis, and the many converted outbuildings across villages like Great Shelford and Sawston take a real battering from freeze-thaw cycles.

What a Roof Coating Actually Does

A roof coating is a liquid-applied product - typically polyurethane, acrylic, or a rubberised compound - that is brushed or sprayed over an existing roof surface to seal minor cracks, restore waterproofing, and extend the roof's working life. It does not add structural strength and it cannot fix rotten decking, failed joists, or widespread membrane failure.

Coatings are most useful on flat or low-pitch felt roofs where the underlying structure is sound but the surface is beginning to crack or blister. On a well-maintained flat roof where the problem is surface weathering rather than deep structural decay, a quality coating can add several years of serviceable life at a fraction of replacement cost. Expect to pay roughly £20-£40 per square metre for a professionally applied coating, depending on the product and the roof's condition.

The National Federation of Roofing Contractors advises that coatings should only be applied to roofs that have been properly assessed and cleaned beforehand. A coating over damp or deteriorating felt will fail quickly and can trap moisture, accelerating the very damage you were trying to stop.

When You Need a New Roof Instead

A new roof is the right answer when the existing covering has failed beyond surface repair, the decking underneath is soft or rotten, or the roof is approaching the end of its natural lifespan. Felt flat roofs typically last 15-25 years depending on quality and maintenance. Modern GRP (fibreglass) and EPDM rubber systems can perform for considerably longer under normal conditions.

Signs that a coating will not solve your problem include:

  • Water staining on ceilings directly below the roof
  • Soft or springy spots when you walk on the roof surface
  • Felt that is lifting, bubbling in large sections, or has cracked through to the decking
  • Repeated leaks that have been patched more than once
  • Visible daylight or gaps around roof edges and abutments

If any of these apply, a coating is a short-term fix that will likely fail within a year or two. A full replacement to GRP or EPDM is a better investment, typically costing £70-£120 per square metre installed, and gives you a fresh, properly warranted surface rather than a patch over an underlying problem.

Planning Permission and Building Regulations

Most like-for-like roof replacements on standard domestic properties in Cambridge fall under permitted development and do not require planning permission. However, if your home is in a conservation area - which covers parts of central Cambridge and several surrounding villages - or if it is a listed building, you should check with the government's planning guidance before committing to any material change. Applying a coating to an existing roof rarely triggers planning requirements, but replacing the covering with a different material occasionally does.

Building Regulations approval under Part L (energy efficiency) can apply to flat roof replacements, particularly if you are also upgrading the insulation layer at the same time. Your contractor should advise you on this before work begins.

Making the Right Choice for Your Property

The honest answer is that a coating is appropriate for a roof in reasonable structural condition that simply needs its waterproofing refreshed. It is not a substitute for a new roof when the underlying structure or membrane has failed. Getting a proper inspection before you commit to either option is the only reliable way to know which applies to your situation.

We focus on fencing, gates, and outdoor structures across Cambridge and the surrounding villages, including Histon and Newmarket, but we understand that homeowners often need trusted advice across several trades at once. Whether you are planning a new fence installation to go alongside a renovation, adding a decking installation to complement your outdoor space, or looking at gate installation as part of a wider property improvement, our team is happy to point you in the right direction.

For a free, no-obligation quote on any of our fencing and outdoor structure services in Cambridge and the surrounding area, get in touch with us directly and we will arrange a site visit at a time that suits you.

Need a price in Cambridge?

We come out, measure up and put the number in writing.

Get a quote
Call Quote