The short answer
A competent person could fit a dry ridge kit, because the parts are sold ready to assemble. But the work happens along the apex, and a kit only works if the ridge board, battens and every fixing are right. Most failures trace back to fitting, not to the kit itself. A mistake may not show until the first gale.
Dry ridge kits are sold in builders' merchants, which makes the job look like a weekend task. The roof they sit on is less forgiving.
Working at height on the apex
The ridge is the highest line of the house, and the work is done leaning over the apex with tools in hand. A fall from there is serious, and a ladder alone is not a safe place to carry a run of ridge tiles. Roofers use scaffold or a tower, edge protection and roof ladders for exactly this reason, and the access often costs more thought than the fitting does.
Is a scaffold needed for a ridge job?
Usually some form of proper access is, and the cost sits in the written price. A scaffold that reaches out over a footpath brings in section 169 of the Highways Act 1980, so a householder hiring one should ask the scaffolder who applies. On a terrace with a narrow frontage, getting safe access up can take more effort than fixing the tiles.
Tiles themselves are heavy and brittle. Carrying a long run of ridge units up a ladder, and passing them across a slope, is where breakage and falls happen.
The ridge board and the batten behind the tiles
A dry ridge kit is only as firm as the timber under it. At the apex a horizontal board, the ridge board, ties the tops of the rafters together. The kit fixes a batten or a set of brackets to that timber, and the ridge tiles are clipped or screwed down to those. If the fixing misses the board, or the board is rotten or split, the whole line is hanging on nothing.
How do you know the timber is sound?
Only by looking at it. When the old ridge comes off, the timber below shows what the roof has been through. Soft patches, old nail holes that have lost their grip, and rafter ends that have drifted apart all change how the new fixings must go in. A competent roofer reads those signs and adapts the layout. Someone fitting a kit from the instruction sheet can easily drive a screw into a gap, or into a board that cannot hold it.
Screw length matters as well. The maker specifies a length and a type, and a shorter screw may bite the tile but not the timber beneath it.
Why kits fail when they are misfitted
Most dry ridge failures share a handful of causes. The ventilated roll is stuck down on dusty or damp tiles, so the edge lifts. The unions where ridge meets hip are cut badly and leave a gap. The tiles are not set level, so one sits higher and catches the wind. And the fixings are too few, or driven so hard that they crack the plastic.
Does a tested kit fix a poor fitting?
No. BS 8612 is the specification that dry-fix kits are tested against, and a kit that passes has been shown to work as a system on a test rig. That says nothing about a ridge board that has been fixed badly or a tile that has been left loose. Our page on dry ridge failure shows where misfitted systems let go, and the page on BS 8612 dry-fix explains what the test covers.
When a home-fitted ridge goes wrong, the repair often means stripping all of it and starting again, because the faults run along the whole length. Bring the kit's data sheet to any survey and we can tell you whether it suits your tile.
What a roofer brings to the job
Fitting a dry ridge is mostly preparation. The roofer checks that the rafters line up, cuts back the roof covering so that the kit sits on firm ground, and lays out the units before fixing a single one so that the last tile does not end as a sliver. At the gable ends and hips, each cut is made to the maker's detail, and the end caps go on last.
Is it cheaper to do it myself?
The materials are only part of the bill. Access, waste removal and the cost of putting right a failed fitting all count. For a typical UK range, see the dry ridge cost page. If you want to see what a proper fitting involves before deciding, our survey starts on your ridge itself, with photos of the timber and the existing units for you, and one written price after it.
That price covers the access, the kit and the clearing away at the end. Our dry ridge and verge page sets out how the whole system is built, which is a good thing to read before you decide who does the work.
More on fitting your own ridge
Do I need building control approval to replace a ridge myself?
A like-for-like ridge replacement is not normally notifiable, but a covering that is 15 per cent or more heavier needs Building Regulations approval. If you are unsure whether your plan changes the weight, ask your building control body before ordering anything, because a refusal after the work is finished is hard to put right.
Can a homeowner buy the same kit that a roofer uses?
Many kits are sold through merchants, so buying is not the problem. The issue is matching the kit to your tile profile and ridge board, then fitting it exactly to the maker's instructions. A kit meant for one tile range will not sit properly on another.
The full picture: Dry ridge and verge repairs in Taunton ยท More short answers