What’s the Real Cost to Replace a Bay Window Roof in Brighton?

Let’s get straight to it. You’re seeing a leak or your bay roof just looks tired, and you want a number. In Brighton, Hove, or Worthing, you’re likely looking at a cost between £900 and £2,500 to replace a typical bay window roof. I know that’s a wide range, but anyone giving you a flat price over the phone without seeing it is just guessing. The final figure comes down to a few critical factors I see every day.

What Are the Biggest Factors That Change the Price?

The quote I give you is based on a proper inspection, not guesswork. Here’s exactly what I’m looking for and what drives the cost up or down.

1. The Material You Choose

This is the big one. Your three main options for a small flat roof like a bay are:

  • GRP Fibreglass: This is my go-to material. It’s seamless (no joints to fail), incredibly tough, and will easily last 25+ years. It’s a superb, modern solution and forms the core of my GRP flat roofing system. It’s a mid-range price-wise but offers the best value long-term.
  • Lead: The traditional choice. It looks fantastic on period properties in Hove, but it’s expensive to buy and requires specialist skill to install. Honestly, it’s also a target for theft, which is a real problem in some areas.
  • Felt: This is the cheapest option upfront, but it’s a false economy. Torch-on felt has seams that will fail over time, especially with the coastal weather we get in Sussex. I replace failed felt roofs all the time that are barely 10 years old.

2. The State of the Timber Deck

This is the number one ‘hidden cost’. The roof covering you see is only as good as the timber deck it’s sitting on. If you’ve had a slow leak for years, chances are the OSB or plywood underneath is rotten and spongy. I won’t ever cover over rotten wood. It has to be cut out and replaced. Until I strip the old roof off, it’s impossible to know the extent of the damage.

3. Insulation and Flashing

Building regulations now often require insulation to be upgraded when replacing a roof. Adding a warm deck with proper insulation will increase the cost, but it will also make the room below warmer and cut your energy bills. Equally important is the connection to the house wall. This requires proper lead flashing, which needs to be chased into the brickwork correctly to create a permanent seal. Botch this, and you’ll have leaks running down your wall.

4. Fascias and Guttering

The edges of your bay roof will have fascia boards. If these are old, rotten timber, now is the time to replace them with low-maintenance alternatives. Swapping them out for new uPVC fascias makes sense while the scaffolding is up and I’m working on the roof anyway.

Can I Just Paint Over My Old Leaking Bay Roof?

Yes, you can. You can go buy a tin of Acropol or some other magic paint-on sealant. It’ll probably stop the drip for a few months, maybe even a year if you’re lucky. But I’ll be brutally honest with you: it’s one of the worst things you can do.

All you’re doing is trapping the damp and rot underneath that new layer. The timber deck will continue to decay out of sight, making the eventual professional repair more extensive and more expensive. It’s a short-term patch that creates a bigger long-term problem. If you’re dealing with an active leak, a quick patch might seem tempting, but it’s not the solution.

So, How Do I Get an Accurate, Fixed-Price Quote?

When I provide a quote, it’s a fixed price. That means you won’t pay a penny more. It includes everything: stripping the old roof, responsible disposal of waste, replacing any rotten timber, installing the new GRP fibreglass system, and all the necessary lead work. You can even track my progress through your own client portal with daily photo logs.

The only way to get a firm cost is for me to see it. I need to get up there, check the condition of the decking, and measure up properly. I offer a free, no-obligation roof inspection across the Brighton and Sussex area. I’ll give you a straight, honest assessment and a clear, itemised quote you can rely on.