Ridge and Hip Tiles: Moss, Loose Mortar and What Cleaning Can Fix
Ridge tiles run along the top of a roof and hip tiles along its sloping corners. They are bedded in mortar on many older roofs, or fixed mechanically on newer dry-ridge systems. Both attract moss, and both are a frequent source of questions after storms.
Why moss grows on ridges and hips
Ridge and hip tiles have rounded or angled faces that collect rainwater along their joints. Mortar between them is porous and holds moisture. Birds perch on ridges, leaving droppings that feed growth. The result is often a line of moss or lichen tracing the top and corners of the roof.
Loose and cracked mortar
Bedding mortar weathers over the years. It cracks, shrinks away from the tile and eventually falls out in pieces, sometimes found in the gutter or on the drive. Moss can grow into those cracks and widen them as it holds water through frost and thaw.
What cleaning can do
Removing moss from ridges and hips by hand improves appearance, stops debris washing down the slope and makes the condition of the mortar visible. Low-pressure treatment slows regrowth on the joints. We avoid pressure washing mortar because it washes out weak bedding.
What cleaning cannot fix
Cleaning will not re-bed a loose ridge tile or replace missing mortar. If a ridge tile rocks when gently pressed, or daylight shows through joints, it needs repair. A tile left loose can be lifted by strong wind.
Dry ridge systems
Many newer roofs use dry ridge and hip systems with clips and seals instead of mortar. These still collect moss along the joints, and seals can perish over time. Cleaning lets you see whether caps and clips are in place.
Combining cleaning and repair
Because we offer roof repairs as well as cleaning, loose ridge or hip tiles found during a clean can be re-bedded or refixed once you have agreed, avoiding a second visit. Our roof repairs page explains what we do.
How to check ridges from the ground
Stand back far enough to see the whole ridge line and look along it. A straight, even line is a good sign. Gaps between tiles, tiles sitting higher or lower than their neighbours, missing pieces of mortar and daylight visible through joints all suggest a problem. Binoculars help. Avoid climbing onto the roof to look.
Birds on the ridge
Ridges are a favourite perch, and droppings feed moss and lichen along the top of the roof. Gaps in ridge mortar can also give birds a way into the roof space. Clearing moss and repairing open joints both reduce this. Any work near an active nest has to wait until the birds have left.
Why ridge problems often show after storms
Strong gusts lift at the highest and most exposed part of the roof first. A ridge tile whose mortar has already weakened can shift in a storm and let water in at the top of the roof. Checking after severe weather is a sensible habit.
Moss on hips versus ridges
Hips run down the corners of a roof and catch water from two slopes, much like a valley in reverse. Moss often grows thicker on the lower part of a hip, where more water passes. Ridges at the top get more sun and wind but also more bird activity. Each part tends to show its own pattern.
Mortar in the gutters
Pieces of mortar found in gutters during cleaning are a useful early sign that ridge or hip bedding is breaking up. We will mention it if we find them.
Timing
Check ridges each autumn before winter storms.
Ask for advice
If you have found mortar in the gutter or a ridge looks uneven, send a photo. Quotes are free across Hampshire, Surrey and Sussex.
Get a free quote
Send a few details and ground-level photos if you have them. We will reply with honest advice and a free, no-obligation quote.
Frequently asked questions
I found mortar on my drive. Is that serious?
It usually means ridge or hip mortar is breaking up. It is worth having checked before a tile works loose.
Does moss damage ridge mortar?
It holds moisture in cracks, which can widen them through frost. Removing it helps.
Can you clean and repair on the same visit?
Yes. Loose ridge or hip tiles found during cleaning can be repaired once you agree.
Do you jet wash ridges?
No. Pressure washing can wash out weak mortar bedding.
What is a dry ridge?
A ridge or hip fixed with clips and seals rather than mortar, common on newer roofs.
How do I know if my ridge tiles are loose?
From the ground, look for uneven tiles, gaps or missing mortar. Do not climb up to test them.
Is re-bedding a ridge a big job?
It depends on how many tiles are affected. A few loose tiles is a common, straightforward repair.
Will moss come back on the ridge?
Treatment slows it, but birds and moisture mean ridges often show the first signs of regrowth.
Pristine Roof Cleaning Solutions is based in Petersfield, covers Hampshire · Surrey · Sussex and is fully insured to £5,000,000 public liability.
Related guides
- Chimney Stack Moss and Staining
Why moss, lichen and dark staining build up on chimney stacks, what it means for the flashing and brickwork, and how chimney stacks are cleaned safely.
- After a Storm: Roof and Gutter Check
What to check on your roof and gutters after a storm, safely from the ground: slipped tiles, displaced ridges, damaged gutters, debris and leaks inside.
- Common Winter Roof Problems and How to Prevent Them
The roof problems British winters cause — freeze-thaw damage, ice in gutters, storm-lifted tiles, condensation — and how to prevent or respond to each.
- Roof Valleys: Why Moss Collects and How It Is Cleared
Why moss, leaves and silt collect in roof valleys, the leak risk when valleys block, and how valleys are cleared by hand without damaging lead or tiles.
Last updated 2026-11-03.