Porch, bay and canopy flat roofs

Guide price: £750–£1,250
Survey: Free for new and replacement roofs
Quote: Fixed, in writing
Coverage: England, Wales, Scotland, NI

What is involved in re-roofing a porch or bay?

Re-roofing a porch or bay means stripping the old felt or failed lead, checking the small deck and its supports, and laying a new membrane that turns up the house wall and drips cleanly over the front edge. On a roof this size the work is mostly edges and junctions.

Strip the old covering and check the deck boards, which on porches are often thin and short-spanned.
Check the fall, so water runs away from the house wall and off the front edge or into a small gutter.
Insulate only where the porch or bay is part of a heated room and the build-up allows.
Form an upstand at the house wall with a flashing let into a mortar joint.
Fit drip trims that throw water clear of the window or door frame below.
Seal around any downpipe, light fitting or bracket that passes through the roof.

Bay window roofs sometimes have a curved or angled front, which suits a liquid or GRP finish better than sheet membrane.

How much does a porch or bay window roof cost?

A typical 4 m² porch or bay roof re-covered in EPDM is £750–£1,250 including VAT. Because set-up, materials and travel are much the same for any roof, small roofs usually sit at or near our minimum charge for a full re-roof, which is £750–£1,250.

Option	Guide price	Suits
4 m² porch or bay in EPDM	£750–£1,250	Square and rectangular roofs
GRP fibreglass rate	£75–£140 per m²	Angled bays and curved fronts
Liquid-applied rate	£90–£140 per m²	Awkward shapes and many penetrations
Minimum charge, full re-roof	£750–£1,250	Very small canopies

If a first-floor bay needs scaffold, add £450–£950. A localised fault on an otherwise sound roof may only need a repair, typically £150–£500. Guide prices only; the fixed price comes after a free survey.

Which material looks best on a porch or bay roof?

For most porches, EPDM rubber gives a neat, dark grey finish that sits quietly on the front of a house, and on a small roof it can usually be laid as one piece. For angled bays and curved canopies, GRP fibreglass or a liquid-applied system follows the shape without folds or joins.

Many older bay windows and porches were finished in lead, which has a distinctive look. Where you want to keep that appearance, especially on a period house, we can discuss a lead-look finish or retaining lead flashings at the wall. On a listed building or in a conservation area, changing from lead to a membrane may need consent, so we check that at survey.

Colour matters more here than on a hidden rear roof. GRP topcoats come in several colours, and EPDM is typically black or dark grey.

Do I need permission to re-roof a porch or bay?

Usually not. Re-covering a porch or bay roof without materially changing how it looks does not normally need planning permission, and an unheated open porch is not usually a thermal element.

The picture changes if the bay or porch is part of a heated room: replacing most of the roof can then bring it under the insulation rules for renovated roofs, which may need building control approval in England, a check in Wales, building standards in Scotland or district council building control in Northern Ireland. On a very small roof, adding insulation may not be technically feasible because of the height available below the window sill above. We assess that at survey.

Listed buildings need consent for changes that affect their character, and conservation areas can restrict changes to the front of a house. See our building regulations page for more detail.

How long does a porch roof replacement take?

Most porch and bay roofs are replaced in a single day, weather permitting. GRP or liquid systems may need a return visit for a topcoat once the first coat has cured.

Disruption is minimal. You may need to use another door while a front porch is being re-roofed, and the area below should be kept clear for safety. A ground-floor bay can usually be reached from a tower or platform steps, while a first-floor bay may need a small scaffold. The window below stays usable, though it is best kept closed while resin is curing.

Why do small porch and bay roofs carry a minimum charge?

Because a small roof needs nearly the same set-up as a larger one: a team, safe access, materials, trims, waste removal and travel. The roof area is only part of the cost.

A 2 m² canopy and a 6 m² bay still both need a full strip, a deck check, edge trims, a wall flashing and the same care at the drip edge. That is why our full re-roofs carry a minimum charge rather than being priced purely per square metre. It is also why bundling makes sense: if you have a porch, a bay and a garage, pricing them together usually works out better than three separate visits.

The junction with the house wall deserves the most attention on a porch. Many leaks blamed on a porch roof are actually water tracking behind a failed flashing or through porous brickwork above. We check the wall, the flashing and the frame head before recommending a new roof. If the problem is only the flashing, a targeted repair may be enough. Our flat roof leaks guide explains how leaks are traced.

What's included when we do the work?

Free survey of the roof, wall junction and frame head
Strip-out of old felt or failed lead
Deck repair or renewal where boards are soft
New EPDM, GRP or liquid membrane shaped to the roof
Wall upstand, flashing and drip trims clear of the frames
Written workmanship guarantee, with material guarantees registered where available

What do guide prices look like?

Guide prices including VAT at West Midlands rates; regional pages adjust these for your area. The fixed price comes after a free survey for new and replacement roofs.

Job	Guide price inc VAT
Porch or bay (4 m²), EPDM	£750–£1,250
Single garage (18 m²), EPDM rubber	£1,600–£2,800
Extension (20 m²), GRP, new deck + insulation	£3,000–£5,400

Does anything differ outside England?

Wales: In Wales, a small porch or bay re-roof may still need approval if more than 25% of a roof over a heated space is being replaced, so check before starting. An open, unheated porch is not usually a thermal element.
Scotland: In Scotland, like-for-like re-covering of a small porch or bay roof can be exempt from a building warrant, but check with the council's building standards service if the work changes the structure or the roof is over a heated room.
Northern Ireland: In Northern Ireland, contact the district council's building control if the porch or bay is part of a heated room and most of the roof is being replaced.

How does the job run from start to finish?

Look and measure
We check the roof, the flashing at the wall and the frame below, and confirm whether repair or replacement is right.
Written price
You get a fixed quote, and we tell you whether combining it with other roofs would bring the cost down.
Re-cover in a day
The team strips the old roof, repairs the deck and lays the new membrane with fresh trims and flashing.
Final check
We check the drip edge and wall junction, clear the site and hand over your guarantee details.

Questions about porch, bay and canopy roofs

Can a bay window roof be replaced without scaffold?

A ground-floor bay usually can, using a tower or platform. A first-floor bay generally needs a small scaffold for safe access.

Should I replace lead on my bay roof with EPDM or GRP?

It depends on the house and your priorities. Membranes usually cost less and have no scrap value to thieves, but on a period or listed property keeping a lead appearance may matter or be required.

Why is my porch roof leaking when the felt looks fine?

The water is often coming from the wall junction, not the roof surface. A failed flashing, cracked mortar or porous brick above can let water in behind the upstand.

Can you re-roof a porch and a garage on the same visit?

Yes, and it is often better value. Combining small roofs spreads the set-up and travel costs.

How long will a new porch roof last?

With good specification and maintenance, EPDM is indicatively 25–50 years and GRP 20–40.

Does a porch roof need a gutter?

Not always. Many small porches drip straight off the front edge, but a gutter helps over a doorway or path.

Can a canopy over a front door be re-covered?

Yes. Small canopies are re-covered in the same way as porches, usually in EPDM or GRP, subject to the minimum charge.

What is involved in re-roofing a porch or bay?

How much does a porch or bay window roof cost?

Which material looks best on a porch or bay roof?

Do I need permission to re-roof a porch or bay?

How long does a porch roof replacement take?

Why do small porch and bay roofs carry a minimum charge?

What's included when we do the work?

What do guide prices look like?

Does anything differ outside England?

How does the job run from start to finish?

Look and measure

Written price

Re-cover in a day

Final check

Questions about porch, bay and canopy roofs

Related services

EPDM rubber roofing

GRP fibreglass roofing

Flat roof repairs

Edge trims, outlets and drainage

Where do you offer porch, bay and canopy roofs?

Get a fixed price for your flat roof