Hip irons
What is a hip iron?
The short answer
A hip iron is a metal strap or bracket fixed at the foot of a hip, below the last capping tile. It catches that bottom tile and stops the run of hip tiles from sliding down the roof. It does not replace fixing each tile, but if it is missing or loose, the hip can creep and open. It is worth checking whenever a hip is repaired.
What a hip iron is, what it holds in place, how it fails and what a roofer does about it when a hip is repaired or rebuilt.
A bracket at the bottom of the slope
On a hipped roof two planes meet along a sloping edge pointing outwards, which is common on bungalows. Capping tiles run down that line from the top of the roof to the eaves, and gravity is always trying to pull them downhill. The hip iron is the answer at the bottom: a shaped strip of metal screwed to the timber beneath the last tile, curved to cup that tile and stop it moving.
Think of it as a stop rather than a fastening for the whole hip. Each tile above leans on the one below, so the bottom one carries a share of the load of the entire run. If it moves, the line shifts with it.
Not every roof has one, and some have been lost through earlier repairs. Our page on hip tile repair describes the rest of the hip, from the junction at the ridge down to the eaves.
How a hip iron fails
The usual failures are simple. The metal can rust through, especially if it was a plain steel strap on an older roof. The screws can work loose from the timber as it dries and shrinks, or the iron can bend when tiles slip against it. In some cases it was never fitted, or it was removed during a past repair and left off.
From the ground the signs show in the line of the hip. The lowest capping tile sits crooked, or there is a gap between it and its neighbour, or the whole run has crept a little way down the slope and left a step near the eaves. Mortar cracks beside the lowest tiles are another clue.
A failed iron on its own is a small repair, but if left, the creeping hip loads the tiles in ways they were not designed for. Cracked tiles and pointing that keeps breaking out are often the result. Photographs from the ground, taken after each storm, help show whether anything is changing.
The iron, the mortar bed and the fixing in each tile
Old-fashioned hip capping is laid in a mortar bed, and the iron holds the foot while the bed holds the rest. Neither is enough alone. Mortar seals the gap and gives the tiles a seat, but it is weak when wind tries to lift or twist a tile.
The 2014 revision of BS 5534 stopped treating mortar as enough for hip capping, so each tile also gets its own mechanical fixing, and Marley asks for the same on every bedded tile and fitting. A hip iron supports that approach at the bottom, but it does not take the place of a screw or clip in every cap.
Marley also notes that installing to BS 5534 is not required by law, which makes it good practice, not a legal test. A roofer should still be able to tell you how every tile on your hip is held. Our guide to fixing ridge tiles explains the same approach on the ridge.
Replacing or adding one
Fitting a hip iron is a small job that happens as part of a hip repair. The lowest few capping tiles are lifted, the old bed is cleared from that section and the timber is checked. If the iron is rusted or loose it comes off, the screw holes are made good in the hip rafter and a new one is screwed down. The tiles then go back with fresh bedding and their own fixings.
If there was never an iron, one can be added when the hip is rebedded. We would not fit one without looking at the whole hip, since a slipping foot often means the bed above has also failed and a patch at the bottom would not hold.
On a dry hip system, the start fitting at the foot does the same job as the iron, held by the maker's own bracket. Our page on ridge end caps describes the finishing pieces on that kind of system.
Checking one from the ground
There is no need to go near the roof. Stand square to the hip and look at the lowest tiles with binoculars or a phone on zoom. The bottom tile should sit snug and in line with the ones above it. A tilted tile, a visible gap or a rust streak down the slope below the foot suggests something is wrong.
Because the foot of a hip is near the eaves, it is often lower and easier to reach than the ridge, but that is no reason to climb up yourself. Loose capping can slide, and a ladder against a guttering that has not been checked can slip.
Send us photographs and we will describe what we can see. After the survey you get a plain verdict and a single written total, and the work is limited to what the hip needs. You can read about the rest of the work on our ridge tile repairs page.
Related questions
Hip iron questions
Does every hipped roof have a hip iron?
No. Many do, but plenty of older roofs never had one, and others lost theirs in earlier repairs. The survey tells us whether yours has one and whether it is sound. If it is missing, it can usually be added when the hip is repaired.
Can an iron be added without relifting the whole hip?
Sometimes only the bottom few tiles need to come off, which keeps the work small. But if the bed above has failed or the tiles are moving, a patch at the foot will not last, and the hip should be dealt with properly in one go. We tell you which case applies.