Rubber Porch Roof Kit – Complete One-Piece EPDM System for Porches, Canopies & Bay Windows, Cut to Size

A complete one-piece EPDM rubber roof for a porch, canopy, bay window or small lean-to — built around the way these roofs drain: a gutter along the front edge, the house wall at the back, and a kerb trim capping each side.

The 1.2mm membrane is cut to your chosen size before it leaves us, so it goes on as one sheet with no on-site joining, and everything is bonded cold — no torch, no flame, no specialist tools. Most porch roofs are finished in an afternoon.

Is this the right kit for your roof?

• ✓ A porch, front-door canopy, bay window, small lean-to or side extension with a flat or low-pitch timber deck from 1.5m × 2m up to 3m × 6m
• ✓ The roof meets the house wall along one edge and drains to a gutter on the opposite edge
• ✓ A timber deck — OSB3, WBP plywood or sound boards
• ✓ You want the whole job in one delivery, fitted in an afternoon with no flame and no specialist tools

Water runs to the front edge, which takes the gutter drip trim with a moulded corner at each end. The two sides are capped with kerb trim. At the back the membrane runs 150mm up the house wall and is covered by the wall flashing trim, with a pre-formed patch sealing each back corner.

Free-standing canopy, carport or bin store? There is no wall to flash, so tell us at checkout or by WhatsApp and we will swap the wall flashing for a third kerb trim at the same price. Use our shed kit instead if the roof is a simple box with no gutter.

Roof bigger than 3m × 6m, L-shaped, or with pipes and outlets to price? Our roof kit calculator prices every line for any shape.

What is in the box

What is not included

For a standard porch roof, nothing else is needed. You may want to add:

• Wall flashing mastic to seal the top of the flashing trim if you are not pointing it with mortar
• An EPDM pipe flashing boot where a flue, soil pipe or cable passes through
• A drain outlet if the roof drains through the deck rather than over the front edge
• Timber and firrings to correct the falls — sourced locally, not something we ship

Choosing the right size

The size on this page is the size of the membrane, not your roof.

The rubber has to reach past the deck on every side: over the front and sides under the trims, and 150mm up the house wall under the flashing. Allow 150mm on each of the four sides. Depth is the front-to-wall measurement; width runs along the house.

All 19 sizes are listed in the selector above, each with the deck it fits. If you fall between two sizes, take the larger one. Surplus membrane trims off in seconds; a sheet 50mm short cannot be rescued.

Size and price my roof Our calculator prices every line for any shape, including L-shaped and pitched roofs.

Specification

How it goes on

1. Prepare the deck and chase the wall

Take the old covering back to the boards. Replace anything soft, punch every nail head below the surface, fill gaps over 5mm and confirm the falls run from the house wall to the gutter edge at 1:80 or better.

Chase a 25mm-deep groove into a mortar joint about 150mm above the deck for the wall flashing. Sweep clean and let everything dry.

2. Relax the membrane, then bond the field

Unroll the sheet with an even overhang all round and leave it 30 minutes to lose its fold memory. Fold half back and roller water-based deck adhesive onto the bare deck, stopping about 150mm short of every edge.

3. Sweep it down into the wet adhesive

Roll the folded half back into the adhesive while it is still wet and sweep it firmly from the fold outwards with a soft broom to drive the air out. Repeat for the second half.

4. Contact-bond the perimeter and the wall

Brush contact adhesive onto the dry perimeter margin, the house wall up to the chase, and the matching underside of the membrane. Wait until both faces are touch-dry, then press the rubber over the front and sides and up the wall, and roll it hard.

Fold and bond the two back corners, then prime them and apply a corner patch over each.

5. Fit the trims and the flashing

Trim the surplus membrane, fit the two moulded front corners first and cut the gutter and kerb trims to meet them. Screw through the face at roughly 250mm centres with a 3mm gap at each joint.

Tuck the wall flashing trim into the chased groove over the top of the membrane and point it with mortar or seal it with flashing mastic.

Why rubber instead of felt on a porch

What porch owners say

Read all customer reviews · Rated Excellent by 1,000+ UK roofers on Trustpilot.

Delivery, dispatch and returns

• Free delivery to UK mainland addresses on every size — including the trims, which most suppliers surcharge.
• Dispatched within one working day — every membrane is cut to your size before it leaves.
• 1–3 working days on a tracked courier once dispatched. Trims travel in a separate rigid pack so they arrive straight.
• Made to measure — the membrane is cut to the size you order, so kits cannot be returned or exchanged once cut unless faulty. Faulty or damaged items are replaced or refunded in full.
• 20-year product guarantee on the membrane; BBA and fire certificates available on request.

Frequently asked questions

Can I fit this myself?

Yes. A porch is the easiest EPDM roof there is: a small sheet, three trims and one wall detail. Everything is cold applied and the trims screw on. Most people finish in an afternoon, and the free manual covers every step.

Which size do I need?

Measure the roof deck, add 150mm to each of the four sides, and order the kit closest to but not smaller than that figure. A 1.2m × 1.7m deck needs the 1.5m × 2m kit. Between sizes, go up — or WhatsApp us a photo and your measurements and we will confirm the size before you order.

Which way round are depth and width?

Depth is the measurement from the house wall out to the gutter edge. Width runs along the house. A 1.5m × 3m kit is 1.5m deep and 3m wide, and the trims are cut to suit that layout.

My porch is free-standing — can I still use this kit?

Yes, with one change. With no house wall there is nothing to flash, so tell us when you order and we will swap the wall flashing trim for a third kerb trim and two more corners at the same price.

Will the membrane have a join?

Every kit is supplied as one sheet at the size you order, so there is no on-site joining required — nothing to tape or overlap on the roof.

What exactly is included?

1.2mm EPDM membrane cut to size, water-based deck adhesive, contact adhesive, gutter drip trim for the front edge, kerb trim for both sides, two moulded front corners, wall flashing trim for the house edge, two corner patches with primer, a tool kit (scissors, roller set, mini roller, paint brush) and all clips and pins.

What colour is the membrane, and can I choose the trim colour?

The membrane is lead / slate grey. The trims come in black, white or anthracite grey — choose above; the price is the same either way. White suits most uPVC porches, anthracite matches grey windows and doors.

How long does a porch roof take to fit?

An afternoon. About 30 minutes of preparation, 30 minutes letting the sheet relax, an hour to bond it, and an hour on the wall detail and trims.

Does the deck have to be dry, and what weather do I need?

Yes. The deck must be completely dry and you want a dry day at 5°C or above with no rain forecast until the adhesive has cured. Water-based adhesive will not bond to a damp deck.

Can I lay EPDM over the old felt?

Only if the felt is fully bonded, flat, dry and free of mineral chippings. On a porch it is usually an hour's work to strip it, and you can then see and fix any soft boards before the rubber goes on.

How long will it last, and is it guaranteed?

The membrane carries a 20-year product guarantee and has a life expectancy of up to 50 years. Felt on the same porch would typically need replacing three to five times over that period.

Is the membrane certified?

Yes — it is BBA certified and fire-tested to BS 476 and EN 13501. If your building control officer or insurer wants the paperwork, email us and we will send the certificates.

Does it cope with standing water?

Yes. EPDM is unaffected by ponding, which matters on small roofs where the fall is often less than ideal. Build in a fall of 1:80 to the gutter edge anyway so the roof drains and stays clean.

Do I need a primer?

Only where supplied: the primer in the kit is for the two corner patches. The water-based adhesive bonds directly to OSB and plywood without it.

Can I walk on the finished roof?

For occasional maintenance in soft-soled shoes, yes. It is not a walking surface for regular traffic, and never walk on it wet or frosty.

How much maintenance does it need?

Ten minutes a year: clear leaves off the roof and out of the gutter, and check the wall flashing after big storms. There is nothing to re-coat or paint.

When will it arrive?

Every kit is dispatched within one working day, then 1–3 working days on a tracked courier. Delivery is free to UK mainland addresses, trims included.

What if I order the wrong size?

Tell us straight away. Every membrane is cut to your size to order, so once it has been cut it cannot be returned or exchanged unless it is faulty. If you contact us before the membrane is cut we can amend the size free of charge — which is why we would rather size it with you first.

Guides that go with this kit

• Fitting edge trims — which trim goes on which edge
• Flashing and detailing — the wall upstand explained
• Forming corners — folding rather than cutting
• Drainage and falls
• The full EPDM Learning Centre