Your New Kitchen Extension Roof: Getting It Right First Time

You’ve spent a fortune on builders, bi-fold doors, and the perfect kitchen island. The last thing you want is a drip landing in your Sunday morning coffee. I’ve been fixing roofs on extensions across Brighton and Hove for over 18 years, and I’ve seen the good, the bad, and the downright cowboys. A kitchen extension flat roof, done properly, is a brilliant, long-lasting asset. Done badly, it’s a constant source of stress. Here’s my straight-talking advice.

What’s the Best Material for a Kitchen Extension Flat Roof?

Forget the old-school felt your grandad had on his shed. Modern materials are in a different league. For most homes in the Sussex area, I recommend one of two main systems:

  • High-Performance Torch-On Felt: This isn’t one thin sheet. It’s a multi-layer system, usually two or three layers bonded together with a torch. It’s tough, flexible, and has a proven track record. A well-installed system will give you 20-25 years of service, no problem.
  • GRP (Fibreglass): GRP creates a completely seamless, hard-wearing plastic shell over your roof. It looks very smart and modern and is incredibly durable. The key is in the preparation of the timber deck underneath and ensuring it’s laid in the right weather conditions.

Frankly, both are excellent choices when installed correctly. The best option for you depends on your budget and the specific details of your roof. You can read more about the modern high-performance flat roofing systems I install.

My New Extension Roof is Leaking! Can I Fix It Myself?

I get this call a lot, especially after heavy Brighton rain. Let’s be blunt. Can you slap something on it to stop a drip for a weekend? Yes.

You can go to a DIY shop, buy a tin of Acropol or some other fibre-reinforced paint, clean the area, and slap it on. It might even work for a few months. But you are not fixing the problem; you’re just hiding it. The water is still getting in somewhere, and it’s quietly rotting the timber roof deck underneath. That small leak becomes a huge structural repair job down the line.

A professional fix involves finding the source, which is rarely where the drip appears. It could be a failed seal around a skylight, a tiny crack in the membrane, or failed flashing where the extension joins the house. If you’ve got a sudden disaster, your best bet is to call for urgent leak repairs to minimise the damage before it gets worse.

What About Skylights and Lead Flashing?

A roof lantern or skylight is the best way to flood your new kitchen with light, but it’s also the number one source of leaks if not installed by a proper roofer. Your builder can frame the opening, but the waterproofing details are critical. The upstands must be perfect, and the junctions need to be sealed flawlessly. This also goes for where the new flat roof meets the brickwork of your house. This joint needs properly installed lead flashing, not a tube of silicone that will fail in a year. It’s these details that separate a 20-year roof from a 2-year problem.

How Much Does a New Kitchen Extension Flat Roof Cost in Worthing or Brighton?

Anyone who gives you a price per square metre without seeing the job is guessing. The cost depends entirely on:

  • The Size: Obvious, but the bigger it is, the more material and labour it takes.
  • The Material: GRP is typically more expensive than a high-performance felt system.
  • Insulation: A ‘warm roof’ design (with insulation on top of the deck) is essential for building regulations and comfort, but adds to the cost.
  • The Decking: Is the existing timber deck sound, or does it need replacing due to water damage?
  • The Details: Skylights, soil pipes, and complex shapes all add time and cost.

I provide fixed-price quotes, so the price I give you is the price you pay. No surprises. You can see more details and get an instant online estimate on my dedicated page on rear extension roofs. You’ll also get access to my client portal with daily photo updates, so you can see the quality of the work for yourself.

My Final Advice

Your roof is the most important part of your new extension. Don’t let it be an afterthought, and don’t choose your roofer based on the cheapest quote alone. Get it done right, once. If you’re in Brighton, Worthing, or anywhere in Sussex and want an honest assessment and a solid roof over your head, book a free, no-obligation roof inspection with me. I’ll tell you exactly what you need.