How Long Does A Flat Roof Last?

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Are you considering a flat roof and wondering, how long does a flat roof last? If you’re about to spend a good deal of money on a flat roof, you’ll want to know how long you can expect it to hold up against inevitable wear and tear. 

There are, in fact, a few different types of flat roofs. Each one is made with different types of materials with their own pros and cons that will affect how long your flat roof is likely to last.

What are the different types of flat roofs, and how long can you expect each one to last? We have all the info and answers you need right here…

Some Notes On Maintenance 

As with all things, general maintenance goes a long way in helping your flat roof stay in good condition. Regular cleaning will keep your flat roof free from debris and unwanted matter that might otherwise cause damage.

Any signs of damage should be repaired as soon as possible to prevent further damage to your property, such as leaks, condensation and mould. Are you unsure what might be tell-tale signs of condensation? Read about the warning signs of condensation here.

What About The Manufacturer’s Guarantee?

You may be thinking, “Why does it matter how long a flat roof lasts anyway? There’s always the manufacturer’s guarantee.”

Unfortunately, while most flat roofs come with a manufacturer’s guarantee, many only cover the materials of your flat roof, such as the waterproofing – not your whole roof. To save yourself time and money, it’s best to check out the small print of any guarantee from a flat roof installation company.

With all that said, even the best care and the most comprehensive guarantee cannot give you an indestructible flat roof. So how long does a flat roof last you? Let’s consider each type of flat roof available…

How Long Does A Felt Flat Roof Last?

Felt Flat Roof

Felt flat roofs are the traditional type of flat roof. Made from thick felt material, it was one of the first materials used to create flat roofs when no other material options were available.

Pros: 

  • Cheap. 
  • Readily available and easy to get hold of.
  • Simple to install with no specialist training required, you can DIY or ask any handyperson to undertake the fitting. Although beware, a poorly fitted felt roof can cause leaks, damage and costly issues in your roof structure. 

Cons: 

  • Unattractive.
  • Cracks and splits in frost and sunlight.
  • Organic matter readily grows.
  • Dimensionally unstable (weathering may change its shape).
  • Any manufacturer’s guarantee only covers the product, not the whole flat roof or workmanship. 
  • Fire risk – installers use a naked flame to fit.
  • No quality control; plenty of faulty and poor felt flat roof products on the market.

How long does a flat roof last when made of felt? You can expect a lifetime of between 8-12 years which is likely to be littered with the above problems.

How Long Does A Glass Reinforced Polymer Fibreglass (GRP) Flat Roof Last?

GRP Flat roof

GRP fibreglass flat roofs are made from polyester resin, reinforced by chopped strand mat glass fibres to form a GRP laminate. It’s very strong yet light, making it a potentially suitable flat roof material. But is it as durable as it sounds?

Pros: 

  • Very strong.
  • Lightweight.
  • Attractive.
  • Cost-effective.

Cons:

  • It’s brittle and will crack rather than flex. This means that when the weather causes the roof to expand and contract, the GRP will crack. 
  • Can only be laid in temperatures between 5-25°C.
  • Resin mixed on the rooftop is likely to spoil if unfavourable weather conditions occur.
  • The resin liquid can vary in thickness with varying levels of protection.
  • GRP will not bond unless the roof deck is 100% dry.
  • Requires brand new roof deck.
  • Subject to tiny hairline cracks that can go unnoticed.
  • GRP is flammable and toxic.
  • Poor elongation or fixings can create cracks and splits over time.
  • Manufacturer’s guarantee only covers the product, not the whole flat roof.

How long does a flat roof last when made of GRP Fibreglass? At the most, you can expect to get 15-20 years, however, it depends on the skill of the installer, whether it was fitted in good weather conditions and the quality of the product used. It’s not uncommon for poorly fitted GRP roofs to fail after as little as 6 months. 

How Long Does An EPDM Flat Roof Last?

Short for Ethylene Propylene Diene Terpolymer Membrane, EPDM is a rubber roofing membrane that’s bonded to the structural deck and typically fixed with glue on site. Considered to be an extremely long-lasting flat roof, but is it?

Pros:

  • Cost-effective.
  • Easy to fit.
  • Readily available.
  • Minimal installation risk with only glue required, not a naked flame.

Cons:

  • Glue can be spoiled by the weather on site.
  • Unsightly, dull and industrial looking.
  • Easily punctured.
  • Vulnerable joins, particularly if applied when too hot, cold or wet.
  • Affected by dirt and damp.
  • Damaged by sunlight.
  • Deterioration is difficult to detect until too far gone.
  • Ballast or clippings are often required to protect against UV damage.
  • Manufacturer’s guarantee will only cover the product, not the whole EPDM flat roof or workmanship. 

How long does a flat roof last when made of EPDM? You’ll be fortunate to get 15-20 years, depending on the quality of installation and top-tier maintenance.

How Long Does A Vanguard PVC Single-Ply Flat Roof Last?

Vanguard PVC Single-Ply Flat Roof

Poly Vinyl Chloride (PVC) flat roofs are made from strong, flexible sheets that are laid and heat-welded into place. It’s a single-ply flat roof system that offers longevity and durability. 

Pros:

  • Can be installed in most weather. 
  • Quick and simple fitting thanks to pre-cut and shaped metals and bespoke fixings.
  • Can be fitted over an existing roof system saving time and money.
  • Only fitted by registered and certified installers so little chance of error.
  • Dimensionally stable, able to withstand normal building movement and stretches without stress.
  • Doesn’t blister, crack or split in frost or sunlight thanks to UV radiating layer.
  • Vapour permeable that allows any trapped moisture to escape.
  • No adverse effects from ponding or standing water due to the welded waterproof membrane.
  • Extremely durable double fusion-welded joins.
  • Little to no maintenance required. It looks after itself.
  • Environmentally friendly, made from 100% recyclable materials.
  • The warranty covers the product for 20+ years.

Cons:

  • A more expensive initial outlay.
  • You can’t fit it yourself. Only certified installers. 

How long does a flat roof last when made of PVC Single-Ply? Guaranteed for 20 years as the minimum standard. Many are still going strong after 40 years or more. Some installers even offer a lifetime guarantee. 

The Long and Short Of Flat Roofs

How long does a flat roof last? It really depends on the type of flat roof you choose. 

The shortest lifespan is the traditional felt flat roof which you’ll be lucky to get 10 years out of. GRP and EPDM flat roofs do better with an expectancy of around 15-20 years, as long as you keep on top of maintenance. But their longevity very much depends on the quality of their (difficult) installation.

The most durable flat roof is the single-ply flat roof, such as the Vanguard system. Guaranteed for a minimum of 20 years and often lasts more than 40 years.

Would you like to know more about the key differences between felt and single-ply roofs? Find the main points in our recent post here.

Before You Go!

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