Felt Roof Tiles Explained: When They Work, When They Fail, and What I Honestly Recommend

What People Really Mean by a “Felt Roof Tile”

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

Traditional concrete or clay tiles on a pitched roof, with a felt membrane underneath
Lightweight bitumen felt shingles that look a bit like tiles, often used on sheds and outbuildings

Both involve felt in some way, but they behave very differently on your roof. In my 18 years on the roof around Brighton, Hove and Worthing, I’ve seen both done well and badly, and the difference is usually in the preparation and the expectations.

If you ask me, I’ll tell you straight: felt has its place, but using it like a “tile” on a main house roof is where a lot of problems start.

Pitched Roofs: The Real Job of the Felt Under Your Tiles

On a pitched tiled roof, the felt you can’t see is just as important as the tiles you can see. It’s usually a breathable membrane, sometimes still called “felt” out of habit.

Here’s what it’s actually there to do:

Backup waterproofing – If wind-driven rain gets under the tiles, the membrane directs water safely into the gutter instead of your loft.
Wind protection – It helps stop draughts and dust being blown into the roof space.
Condensation control – Modern breathable membranes let moisture escape from inside the house while keeping water out.

When I strip an old pitched roof, the two most common hidden problems I find are rotten battens and torn, sagging felt behind the tiles. The tiles might look fine from the street, but the underlay has quietly failed over decades.

Typical Felt-Related Problems on Tiled Roofs

Here are the issues I’m called out to all the time where the “felt under the tiles” is the real culprit:

Perished felt at the eaves – The felt rots and disintegrates just above the gutter, so any water running down the membrane drips into the soffit or behind the fascia instead of the gutter.
Sagging felt between rafters – Old, heavy bitumen felts drop over time, creating little water pockets that eventually find their way through nail holes and joints.
Condensation in the loft – Non-breathable felt combined with poor ventilation leads to mouldy rafters, damp insulation and that musty loft smell.
Split felt around valleys and abutments – Anywhere the roof changes direction or meets a wall is under more stress, and old felt can crack there first.

All of these can cause leaks or damp patches without a single broken tile in sight. That’s why, when I talk about a full tiled roof refurbishment, I focus a lot on the membrane and battens, not just the tiles themselves.

If you suspect your felt under the tiles has failed and you want a proper look, you can book a free roof inspection in Brighton and Sussex and I’ll check it from the loft and from the outside.

Replacing Battens and Felt Under Existing Tiles

Many homeowners ask me: “Can you just change the felt under my tiles without doing a whole new roof?” In some cases, yes – but it has to be done properly.

My honest approach to batten and felt replacement looks like this:

Strip and stack tiles carefully – I lift the tiles and stack them safely so the good ones can be reused, which keeps costs down.
Remove rotten battens and old felt – All defective timber and underlay has to go, not just the obvious bits at the eaves.
Fit a modern breathable membrane – This improves ventilation and helps prevent future condensation issues.
Install new treated battens – Fixed at the correct gauge for your tile type so they sit properly and don’t rock or rattle.
Relay tiles and replace broken ones – I refit your existing tiles wherever possible and swap out any cracked, spalled or damaged pieces.

If you want a clearer idea of how this sort of job is priced, you can read how I handle a full roof batten and felt membrane replacement step by step.

Bitumen “Felt Roof Tiles” and Shingles on Sheds and Outbuildings

The other thing people often mean by “felt roof tiles” is those strip shingles you see on garden sheds, playhouses and sometimes low pitches on extensions. They’re usually thin bitumen-based products designed to look a bit like overlapping tiles.

Used in the right place, they’re fine. Used in the wrong place, they fail quickly.

Here’s where they make sense:

Small garden sheds – Where a 10–15 year life is acceptable and access is easy.
Summerhouses and playhouses – As long as the roof has enough pitch and is well ventilated.
Temporary structures – Where you know you’ll rebuild or replace in the medium term.

Here’s where I don’t recommend them:

Main house roofs – They are not a long-term solution for a habitable building.
Very low-pitched or flat roofs – Water sits in the “tile” indentations and finds its way in.
Exposed coastal positions – Around Sussex we get strong winds; poorly fixed shingles can lift easily.

On garages and extensions, I nearly always advise stepping up to a proper flat roofing system instead of decorative felt shingles, especially if the space below is important to you.

Common Installation Mistakes I See with Felt Shingles

In my 18 years on the roof, I’ve noticed that most problems with felt shingles aren’t the product itself, but how it’s fitted. The usual mistakes are:

No solid deck – Shingles need a good, continuous timber deck. Fitting over warped or spaced boards leads to splits and early failure.
Wrong pitch – Trying to make them work on almost-flat roofs. The rain just doesn’t clear fast enough.
Inadequate fixings – Too few nails, the wrong type of nails, or nails driven too high where they’re not covered properly.
No underlay where it’s required – Some systems need a full underlay beneath; skipping it to save a few quid can cost you a new roof later.

If you’re unsure whether your felt shingles are suitable for your garage or extension, I’m always happy to have a look and give you an honest opinion on site.

Garage and Extension Roofs: Felt Tiles vs Proper Flat Roofing

Garages, porches and rear extensions are where I often see homeowners trying to use “felt roof tiles” or shingles as a cheaper alternative to a proper flat roof. I understand the thinking, but this is where a lot of leaks start a few years down the line.

Here’s how I look at it in plain terms:

Aesthetics vs lifespan – Felt shingles can look more “tiled” from the garden, but a good torch-on felt system will outlast them and handle pooling water better.
Use of the space – If you’ve got a workshop, utility room or home office under that roof, it needs reliable waterproofing, not just something that looks the part.
Access for future work – Garages often become storage walls for cables and pipes; you don’t want to be patching leaks every winter.

For most garages, I recommend a proper flat roof system instead of felt shingles. If you’re weighing up options, you can use my garage flat roof cost calculator to see what a long-term solution is likely to cost before I even visit.

The same goes for rear extensions. If that’s where your kitchen, dining room or living space is, a decorative felt “tile” effect isn’t worth the risk. A robust flat roofing system will always be my first suggestion on a rear extension, and you can see how I approach these on my rear extension flat roof page.

When a “Felt Tile” Leak Becomes an Emergency

Sometimes a single slipped strip of felt, a torn membrane under tiles or a badly sealed shingle joint can turn into a sudden leak during a storm. If water is actively coming in, damaging electrics, ceilings or flooring, that’s when it moves from “nuisance” to “urgent”.

In those cases, I don’t waste your time with sales chat. I get the roof temporarily secure first – even if that’s just a controlled, targeted patch – and then we talk about whether a proper repair or partial renewal is needed once things are dry.

If you’re in Brighton or nearby and you’ve got water coming through right now, you can use my priority emergency leak booking service so I can get you on the schedule as quickly as possible.

Lead Work and Felt: The Hidden Joint That Often Fails First

Whether it’s a tiled roof with felt underlay or a felt-shingle covered porch, one of the most common weak spots I see is where the roof meets a wall or chimney. The felt or membrane might be fine, but the lead flashing above it has split, slipped or been sealed with cheap mastic years ago.

I always tell customers: flashing is not the place to cut corners. You can have the best felt or tiles going, but if water is sneaking in at the junctions, you’ll still end up with damp.

On site, I check:

How the felt or membrane is lapped into or behind the lead
Whether the lead is chased into the brickwork properly, not just glued on
If there’s any cracking, splitting or poor previous patch repairs

If your leak seems to be along a wall or chimney rather than in the middle of the roof, it might be more of a flashing issue than a felt problem. You can see how I handle this kind of work on my lead flashing repair and installation page.

How I Help You Decide: Keep, Repair or Replace?

Here’s my honest advice if you’re currently dealing with “felt roof tiles” in any form:

If it’s the felt under tiles – Don’t ignore sagging, torn or missing felt at the eaves. It’s a sign the rest of the membrane might be at the end of its life.
If it’s felt shingles on a shed – A tidy re-felt can be fine if the structure is sound and you’re realistic about the lifespan.
If it’s a main house, garage or extension – Think long-term. A proper pitched or flat roofing system is usually better value over 15–25 years than decorative felt tiles or shingles.

When I come out to have a look, I keep it simple: I show you photos, explain what I see in plain English, and then break down a couple of realistic options with fixed prices. No pressure, no upselling, just what I’d do if it was my own place.

If you’re not sure what type of “felt roof tile” situation you have, send me an enquiry and some photos, or book a free inspection. I’ll give you a clear, no-nonsense plan so you know whether it’s something that needs urgent attention or just sensible budgeting for the next few years.