Tile Felt Roofs in Sussex: Honest Advice on Re‑Felting Under Your Roof Tiles

When Customers Ask Me About the “Felt” Under Their Roof Tiles

When customers ask me about a “tile felt roof”, they usually mean one of two things:

The black or green felt they can see hanging into the gutters under their roof tiles.
The old, brittle membrane in the loft that’s starting to rip or let water through.

In my 18 years on the roof around Brighton, Hove and Worthing, I’ve seen the full range – from roofs where the tiles are fine but the felt is completely perished, to roofs where the felt is doing all the work because the tiles and battens are past it.

This page is not about choosing tiles vs flat roofs. I already go into that elsewhere. Here I want to focus on one specific thing: the felt under your tiles – what it does, when it can be repaired on its own, and when it really needs a full strip, new battens and new breathable membrane.

What the Felt Under Your Roof Tiles Actually Does

If you ask me, I’ll tell you straight: the tiles are not the only thing keeping the rain out.

On a typical pitched tile roof you’ve actually got a layered system:

Tiles on top – the first defence against rain and wind.
Battens – the timber strips the tiles hook onto.
Felt or breathable membrane – the hidden waterproof layer under the battens.

The felt (or modern membrane) has three main jobs:

Catch wind-driven rain that gets under the tiles.
Guide any water safely into the gutter instead of into your loft.
Help with draughts and dust blowing into your roof space.

On older Sussex houses, that “felt” is usually a traditional bitumen-based sarking felt. On newer roofs, it tends to be a modern breathable membrane. Both can work well if they’re installed properly and kept away from standing water and UV light.

Typical Problems I See With Tile Roof Felt in Sussex

In my day‑to‑day work, these are the most common issues I find with the felt under tiled roofs:

1. Felt Rotted or Perished at the Eaves

Probably the number one complaint I hear: “There’s a bit of felt sticking into the gutter and it looks ripped and rotten – is that a problem?”

Over time, UV light and constant wetting at the very bottom edge of the roof can rot felt away. Once that happens, any water that gets under the tiles near the edge has a straight path onto the fascia, into the soffit, or down the cavity wall.

Signs you might notice:

Felt hanging into or curled up inside the gutter.
Rotting or wavy fascias near the bottom of the roof.
Water staining on the top corners of the walls inside.

2. Felt Sagging Between Rafters

Old felt can become baggy and sag down between the rafters. That creates little ponds of trapped water. Over time, those ponds find a way through nail holes or small splits and you start to see random drips in the loft after heavy rain.

3. Tears Around Valleys, Chimneys and Hips

Anywhere there’s a change of direction – valley, chimney, hip, dormer – the felt or membrane is more complicated to fit. If it’s not lapped and supported correctly, it can tear or pull away over the years, especially in strong coastal winds.

When that happens, water that should run neatly down and out can spread sideways and emerge as a mysterious leak somewhere completely different.

4. Condensation Issues With Old Non‑Breathable Felt

Old tile felt isn’t breathable. In the days of draughty houses and open fires that wasn’t always a problem. In modern, well‑sealed homes, warm, moist air can end up in the loft and has nowhere to go. It can condense on the underside of the felt, giving you:

Dripping rafters or damp timbers in winter.
Black mould on the back of the felt or on roof timbers.

Sometimes that gets misdiagnosed as a “leak” when it’s actually more about ventilation and the type of membrane you’ve got.

Can You Just Replace the Felt Under Roof Tiles?

This is where people are often given half‑truths. I hear variations of this all the time:

“Can you just slide new felt in from the bottom without taking the tiles off?”
“Could you just felt the problem area instead of the whole roof?”

Here is my honest advice based on what I see locally.

Temporary Felt Repairs at the Eaves

If the only issue is rotten felt at the very bottom of the roof, and the rest of the roof is in good shape, there is a recognised repair called an eaves felt replacement or felt support tray repair.

In simple terms I:

Carefully lift and remove a few rows of tiles at the bottom.
Cut back the rotten felt to solid material.
Fit rigid support trays that sit under the old felt and over the fascia.
Relay the tiles properly, checking the batten condition as I go.

This doesn’t “re‑felt” your whole roof, but it does restore the water path into the gutter and protects the vulnerable eaves area for a good few years.

Why Sliding New Felt in From Below Is a Myth

If someone tells you they can “slide” new felt all the way up under your existing tiles without stripping them, I’d be very cautious.

On a standard tiled roof, the battens sit on top of the felt. You physically can’t pass a full sheet of new felt under the battens without cutting it into small useless pieces or hacking the existing layers. Even if someone tries, you end up with:

Poor laps where water can still get through.
No proper fixings to the rafters.
Bits of felt bunched up, creating more weak spots than you started with.

In my 18 years, I’ve never seen a “magic sliding felt” repair that I’d be happy to put my name to.

When a Full Strip and New Membrane Is the Only Sensible Option

Once the felt or membrane is failing in the main area of the roof (not just the eaves), any honest roofer will tell you the proper solution is:

Strip the tiles and old battens.
Inspect the rafters for damage.
Fit a new, modern breathable membrane to manufacturer guidelines.
Install new battens and then relay suitable tiles.

If you want a clear breakdown of how I approach that and what it costs locally, have a look at how I price roof batten and felt replacement in Brighton and Sussex.

Old Felt vs Modern Breathable Membrane: Does It Matter?

A lot of older Sussex houses still have the original black felt from the 60s, 70s or 80s. I’m often asked if it’s “worth” changing it to a breathable membrane just for the sake of it.

Here’s how I look at it on site:

If your old felt is sound, not sagging, and you’ve got no damp or condensation issues, I don’t push you to change it just because it’s old.
If you’re already doing major work – like a re‑tile or a big structural change – then swapping to a breathable membrane at the same time almost always makes sense.
If you’ve got condensation problems and poor loft ventilation, changing to a breathable membrane can be part of the solution, but I also look at air flow, insulation levels and trickle vents.

Modern membranes, when installed properly, can help your roof space stay drier and reduce the risk of timber rot, especially in tightly sealed, well‑insulated homes.

How I Decide If Your Tile Felt Can Be Repaired or Needs Replacing

I don’t guess from the ground. To give you honest advice, I need to check two areas: from outside and from inside.

1. External Check: Tiles, Eaves and Gutters

Outside, I’m looking for:

The condition of the tiles – cracked, porous or slipping?
How much of the felt is visible in the gutter and what state it’s in.
Any obvious dips or sags along the roof line.
The condition of fascias, soffits and gutters – often the first to show felt problems.

If your guttering and fascia boards are already suffering, I might recommend combining any felt or membrane work with new uPVC fascias or updated guttering and downpipes so the whole edge of the roof is sorted in one go.

2. Internal Check: Loft or Roof Void

Inside the loft, I’m looking for:

Any signs of actual water ingress – staining, mould, soft timbers.
The type and condition of the felt or membrane.
Sagging between rafters or big rips and holes.
Ventilation – soffit vents, roof vents, or just a very sealed space.

Between those two views, I can usually tell you fairly quickly if you’re a candidate for a simple eaves felt repair, a localised fix, or if it’s time to plan a more substantial strip and re‑felt.

Tile Felt Roofs and Other Parts of Your Home

One thing I always explain on site is that the felt or membrane under your tiles isn’t working in isolation. Around Sussex, the roofs I’m most often called to sort are the ones where different roof types meet and the detailing around the felt has been ignored.

Where a Tiled Roof Meets a Flat Roof

On many terraces and extensions in Brighton and Hove, a pitched tile roof runs straight onto a felt flat roof at the rear. If that junction is rushed or the felt under the tiles isn’t lapped correctly, you can end up chasing the same leak for years.

Because I specialise in both pitched and flat roofing, I look at that whole area together. If I’m working on your tiles and underfelt, and you’ve got an older flat roof below, I’ll be honest if I think you’d be better off planning a proper flat roof upgrade at the same time rather than constantly patching around a weak joint.

Chimneys, Parapets and Felt Detailing

Where your tile felt runs up against chimneys, parapet walls or firewalls, it should be lapped neatly into flashings or cappings. If the membrane has been cut short or never tucked in properly, water will find its way behind and you’ll start seeing damp patches around chimney breasts or upstairs fireplaces.

In those cases, I often combine felt and membrane repairs with proper lead flashing work or, on flat parapet tops, new felt cappings to protect firewalls and parapets.

Scaffolding and Access for Tile Felt Work

Any serious work on the felt or membrane under your tiles usually means spending a fair bit of time at the eaves, on the roof face, or working around valleys and chimneys. That’s where safe, sensible access matters.

For small, low‑level eaves repairs I can sometimes work from ladders and a small tower. But for anything larger – long runs, high roofs, awkward extensions – I’ll normally recommend scaffolding. It keeps me safe, allows me to work properly, and stops us rushing jobs that need care.

If you want a rough feel for the access costs before we even meet, you can use my scaffolding price calculator to get a ballpark figure.

When to Worry About Your Tile Felt – And When Not To

Let me be clear: seeing a bit of tatty felt in the gutter doesn’t automatically mean your whole roof is finished.

You should think about getting things checked if:

You’ve seen water staining at the top of your walls or in the loft.
Your fascias or soffits are starting to rot or bow.
There are noticeable dips in the roof, or many slipped tiles.
You’re getting recurring leaks near a chimney, valley or where a flat roof meets tiles.

On the other hand, if your tiles look straight, your ceilings are dry and the only issue is a scruffy felt edge at the gutter, I’ll usually explain your options calmly and help you decide whether a small repair is worth doing now or whether it’s something to plan for when other work is needed.

My Straight Advice If You’re Worried About the Felt Under Your Tiles

In my 18 years on Sussex roofs, I’ve seen two big mistakes:

People paying for quick fixes that never really address rotten or perished felt.
People being pushed into a full re‑roof years before it’s genuinely required.

My approach is simple: I inspect, I take photos, I explain what I see in plain language, and I give you options. If a small, targeted repair to the felt is realistic, I’ll say so. If the felt and battens are at the end of their life, I won’t pretend otherwise.

If you’d like me to come out, have a proper look and give you an honest opinion, you can book a free roof inspection in Brighton and Sussex. I’ll tell you exactly where you stand and what I’d do if it were my own house.