LF Flat Roofing · Sussex

Flat Roof Replacement Sussex

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No call-out fee. No obligation. We’ll visit, assess and quote.

Recognise Any Of These? Your Flat Roof May Need To Be Replaced.

Most flat roofs reach a point where repair stops being the right answer. The cost of repeated patches starts to approach the cost of a full replacement, and each repair lasts a shorter time than the last. The six signs below are the ones we see most often on Sussex properties; if more than one applies, a free survey will tell you whether it’s time.

Multiple Repairs in the Last Few Years

If you’ve had three or more repairs to your roof, the substrate is usually the issue, not the surface. Patching a failing deck only buys time; replacement gives a 20+ year fix.

Sagging or Soft Spots Underfoot

A roof that gives slightly when walked on indicates rot in the deck below. Once the timber is wet, no surface treatment will save it. The roof needs lifting and the substrate replaced.

Pooling water

Water that sits on the roof for more than 48 hours after rain points to incorrect falls; usually because the original roof was built without a tapered insulation system. Replacement with corrected falls fixes it permanently

Bubbling, Blistering or Cracking Felt

Once felt starts to bubble or crack, the layers below are de-bonding. Patches won’t reattach to the system. A full re-felt or change of system is the only lasting fix.

Internal Water Stains or Mould

If you can see staining on the ceiling or walls below the roof, water has been getting in for a long time. Even after the leak is found, replacing the whole roof is often cheaper than repairing the ceiling, the leak, and the surrounding damage.

The Roof Is Over 20 Years Old

Most felt roofs reach end of life at 15–20 years. Older systems are brittle and won’t hold sealant or patches. Modern GRP and EPDM systems last 20–50 years; so replacement now is an upgrade, not just a like-for-like swap.

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Choosing The Right System

Flat Roof Replacement: GRP, EPDM or Felt?

There is no single “best” system for every flat roof. The right answer depends on the size and shape of the roof, the substrate underneath, the exposure of the property, and the budget you’re working with. We install all three main systems (GRP fibreglass, EPDM rubber, and torch-on felt) and recommend whichever fits the job, not whichever earns the most.

On survey we lift a small section of the existing roof to check the deck condition, measure the falls, identify any drainage or detail issues that need correcting, and look at how the roof meets walls, parapets, and upstands. The written quote covers the full system, any decking work, insulation upgrades if appropriate, and a water test on completion.

Most domestic flat roof replacements take two to four days from start to finish. We work cleanly, protect your property and garden, and remove all waste from the site on completion. Photo records are provided at handover so you have a permanent record of what was installed and how.

20-50 Year Lifespan

Lifespan range across modern flat roofing systems — GRP, EPDM and felt all give long service when fitted correctly.

10yr guarantee

Every replacement comes with a written workmanship guarantee on top of the manufacturer’s product warranty.

2-4 Days

Typical install time for a domestic flat roof replacement, including decking and falls correction.

100% Water-tested

Every replacement is water-tested on completion before we sign the job off.

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Icopal-approved installation. Water-tested on completion.

Why Choose Us

Why Sussex Homeowners Choose LF Flat Roofing​

From the first call to the finished roof, here is what you can expect.

Icopal-Approved Contractor

We are trained, tested and certified to install and guarantee Icopal roofing systems to the highest standard.

10-Year Written Guarantee

Every replacement comes with a written workmanship guarantee on top of the manufacturer’s product warranty.

Honest Expert Advice

We install GRP, EPDM and felt, and we recommend whichever fits the job, not whichever earns the most. If repair will do, we’ll always say so.

Free Survey, No Obligation

We visit, lift a section of the existing roof to check the deck, and give you a fixed written quote. No call-out fee, no pressure.

Tidy, Professional Workmanship

We protect your property and garden, work cleanly, and remove all waste on completion. You’ll see the new roof, not the mess of getting there.

Photo records at handover

We document every stage of the replacement so you have a permanent record of the deck condition, the insulation, the membrane, and the finished detail.

How it works

What Happens When You Call LF Flat Roofing?

From the first call to the finished roof; simple, transparent, no surprises.

Step 01

Free survey

We visit, lift a section of the existing roof to check the deck, measure the falls, and assess all the detail work — upstands, skylights, drainage.

Step 02

Written quote

Fixed price, system recommendation, materials and timescales clearly explained. Sent within 24 hours of the survey.

Step 03

Repair/Replacement

Old roof stripped, deck checked and replaced where needed, insulation upgraded if specified, new system installed to manufacturer spec.

Step 04

Handover

Water-test on completion, photo records of every stage, and the 10-year written guarantee provided on handover.

Real customers

What Sussex homeowners say about LF Flat Roofing

"LF Roofing have replaced the roof lights in my bungalow, they did a brilliant job, I’ve used them before to replace the roof felt and insulate my flat roof bungalow. They are always courteous and professional, clean up after the job and remove the old materials when it’s completed."
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Verified Checkatrade Reviewer
Homeowner, Lancing
"Replaced old flat roof on a converted garage with a warm roof. Cannot fault the workmanship on a great job. Extemely satisfied with end result. Very reasonable price in line with quotes. Would have no hesitation in using again and certainly recommend Liam to anyone thinking of flat roof repairs you will be more than satisfied."
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Homeowner, Brighton
"Liam came recommended to us and we are so glad we asked him to carry out the work. Always professional, polite and was always available to answer any questions I had. I have no hesitation in recommending LF Flat Roofing to family and friends. Highly competitive quote and nothing was ever too much bother."
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Verified Checkatrade Reviewer
Homeowner, Crawley

Frequently asked questions

Find answers to common questions about our flat roofing services.

How long does a flat roof replacement take?

Most domestic replacements take 2–4 days. Larger or more complex jobs (multiple roof areas, full insulation upgrade, scaffold required) may take a week. We confirm timescales in your written quote.

Repair makes sense for an isolated leak on a sound roof under 15 years old. Replace when you’ve had multiple repairs in a short period, when the deck is soft underfoot, or when the existing system is at end of life. We’ll give you an honest verdict on survey.

It depends on the roof. GRP is excellent for extensions and complex shapes; EPDM is the long-life choice for larger flat roofs and coastal exposure; felt remains the most cost-effective overlay where the deck is sound. We compare options on survey and recommend what fits your roof and budget.

A typical 20m² extension replacement runs from around £2,500–£4,500 depending on system, condition of the deck, and access. Larger or more complex jobs can run higher. We give a fixed written quote at survey — no estimates, no surprises.

Often yes — for any roof above ground floor or where safe access can’t be achieved with a tower. Scaffold is included in the quoted price where needed; there are no surprise additional charges later.

Yes — replacement is the right time to upgrade. PIR insulation above the deck stops condensation, reduces heat loss, and complies with current building regulations. We can quote with and without the warm roof upgrade so you can see the difference.

Still have a question? Call us on 07793 436 150
Ready To Get Started

Free survey.
Written quote.
No pressure, ever.

We’ll visit your property, assess the roof and give you an honest recommendation with a fixed written price. If a repair will do the job, we’ll tell you.

Book your free survey

No call-out fee. No obligation. We’ll visit, assess and quote.

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