Chimney Scaffolding

Chimney scaffolding: safe access to the stack, without wrecking the roof

Most chimney work is a short job on the most awkward part of the house to reach. The stack sits at the ridge or the gable, two or three storeys up, surrounded by a roof that will not take a ladder’s weight and was never meant to be walked on. We build chimney scaffolds across Oxfordshire, Buckinghamshire, Bedfordshire and south Northamptonshire for repointing, flashing, pots and cowls, rebuilds and full removals, and we price the access honestly, because on a chimney the scaffold can cost more than the repair.

Why a chimney needs a scaffold, not a ladder

A chimney stack is roof work, and roof work is where falls from height kill the most people in UK construction. The Work at Height Regulations 2005 require that falls are prevented where it is reasonably practicable, and HSE guidance on roof work is clear that edge protection at the eaves is the starting point for anything more than the shortest job. A ladder and a roof ladder leave the person at the stack with nothing between them and the gutter.

Chimney work is rarely short. Repointing needs the mortar to cure; a lead flashing needs cutting, dressing and checking; a rebuild is days of bricklaying on a roof; and the weather stops all of it. A scaffold gives a boarded platform round the stack, guardrails and toe boards, somewhere to put tools and materials, and safe access from the ground — and it lets the work be done properly rather than quickly.

The four kinds of chimney scaffold

Which one you need depends almost entirely on where the stack is.

Gable-end chimney scaffolds

The gable-end stack is the friendly case. A tied independent scaffold goes up the gable, with lifts at the working heights and a platform wrapped round three sides of the stack above the roofline. Access is by internal ladder with a gate at each lift. What makes it harder is room: a gable that sits a metre from the neighbour’s fence, a side passage with bins and meters, or a conservatory against the gable all change the base and the price. If the side of the house is a public footway, the scaffold needs a highway licence.

Roof-mounted chimney scaffolds

For a stack at the ridge — the usual arrangement on Victorian and Edwardian terraces, and on many semis — there are two parts. First, an eaves scaffold along the elevation, with a boarded platform, double guardrails and toe boards, so that nobody can fall from the roof edge. Second, a chimney platform built round the stack: standards on spreader boards laid across the roof slopes, so that the load goes into the roof structure rather than through individual tiles or slates, braced across the ridge and boarded at the working height. Roof access staging or a properly secured roof ladder links the two.

The roof covering is the thing to protect. Clay tiles and natural slate crack under point loads; concrete tiles are tougher but still break at the nibs. We spread every load, keep the number of people and materials on the roof platform to what the job needs, and photograph the roof before we start so that there is no argument about what was cracked before and what was cracked after.

Shared and party-wall stacks

On terraces and semis the stack is usually a party structure. Two practical consequences follow. First, the scaffold or the chimney platform may have to stand on, or overhang, the neighbour’s roof or garden, and that needs their agreement before we arrive — a scaffold cannot be put on someone else’s property without consent. Second, the work itself may fall under the Party Wall etc. Act 1996, particularly if the stack is being rebuilt, lowered or taken down, in which case notice has to be served on the neighbour. That is the homeowner’s or builder’s job rather than the scaffolder’s, but it is worth sorting out before the scaffold goes up rather than while it stands idle.

What chimney work the scaffold is for

• Repointing — the commonest chimney job. Raking out and repointing a weathered stack, in lime on older houses.
• Flaunching — the mortar bed at the top of the stack that holds the pots and throws water off. Cracked flaunching lets water straight down the stack.
• Lead flashings and soakers — where the stack meets the roof. The commonest cause of a damp chimney breast inside.
• Pots, cowls and caps — replacing broken pots, fitting bird guards and rain cowls, capping disused flues with ventilation.
• Rebuilding — taking a leaning, spalled or frost-damaged stack down to sound brickwork and rebuilding it.
• Lowering or removal — taking the stack down to below the roofline and making good the roof, or removing it altogether.
• Flue liners — for a new stove or fire: the liner goes down from the top, which needs a safe platform at the pot.
• Aerials, dishes and lightning protection — fixed to or removed from the stack.

Removing a chimney: the approvals people forget

Removing or lowering a stack is the chimney job most likely to run into approvals, and the scaffold usually goes up before anyone has checked. Three regimes can apply:

• Planning and conservation. In a conservation area, and on any listed building, councils can and do treat chimney stacks as part of the character of a street. Removing a visible stack may need planning permission or listed building consent, and councils have ordered stacks that were taken down without it to be rebuilt. Check with the district or city council first.
• Building regulations. Taking out a chimney breast inside the house is structural work, and so is anything that leaves the stack above supported differently. It normally needs a structural design and building control approval before the work starts.
• The Party Wall etc. Act 1996. If the stack or breast is on a party wall, notice is usually required.

None of these is for the scaffolder to decide, but all of them affect the scaffold. A stack that cannot come down until consent is granted is a scaffold standing on hire while nobody works from it.

Chimneys on old and listed houses

Much of the chimney work in our area is on old buildings: tall, decorative Victorian stacks in Oxford’s Jericho, Summertown and east Oxford, Cotswold stone stacks in west Oxfordshire and the Cotswolds, and brick and flint across the Chilterns. On those houses the scaffold has its own constraints. Ties go into joints and openings rather than into soft brick or stone faces; nothing is fixed to the stack being repaired; the roof covering is often original and fragile; and a listed building’s owner will want the same care taken over the parts of the house the scaffold touches as over the stack itself.

The rules a chimney scaffold is built to

• Work at Height Regulations 2005 — fall prevention, and inspection of the scaffold before first use, at intervals not exceeding seven days and after bad weather. See our page on scaffold inspections.
• TG20:21 — NASC guidance for tube-and-fitting scaffolds. A straightforward gable or eaves scaffold comes with a TG20 compliance sheet; a roof-mounted chimney platform is outside TG20’s standard configurations and is built to our own designed arrangement.
• BS EN 12811-1 — duty class. Repointing and flashing is light duty; a rebuild with bricks on the platform needs a heavier duty, and the platform is boarded and loaded accordingly.
• HSE guidance on roof work — edge protection at the eaves of the slope being worked on, and safe access across the roof.
• CDM 2015 — on a domestic job the homeowner’s client duties pass to the contractor doing the chimney work.

CISRS-qualified and CITB-trained scaffolders, Advanced CHAS accredited, £10 million public liability, and a handover certificate on every scaffold.

Highway licences for chimney scaffolds

If any part of the scaffold stands on a public pavement or road — common on terraced streets, where the front of the house is the footway — it needs a licence from the highway authority. That is Oxfordshire County Council in Oxfordshire, Buckinghamshire Council in Buckinghamshire, Milton Keynes City Council in Milton Keynes, Bedford Borough, Central Bedfordshire or Luton Borough in Bedfordshire, and West Northamptonshire Council in south Northamptonshire. We apply for it as part of the job and build the council’s notice period into the programme.

How long chimney scaffolding is up for

Most chimney jobs are short, but they are weather-dependent. As a guide:

• Pots, cowls, caps and a flaunching repair — a few days of work; one to two weeks of hire allows for the weather.
• Repointing a stack and renewing the flashings — one to two weeks.
• Rebuilding a stack from the roofline — two to three weeks, longer in lime or in winter.
• Removal and making good the roof — one to three weeks, once any consents are in place.

The hire period is written into the quotation with erection and strike included, and an extension rate stated in case the weather or the job runs on.

How much does chimney scaffolding cost?

There is no single price, because the four kinds of chimney scaffold are very different amounts of work. The number moves on:

• Where the stack is — a gable stack from the ground is usually cheapest; a ridge stack needs an eaves scaffold and a roof platform.
• Height — two storeys or three, and how far the stack rises above the ridge.
• Access to the side or front — room to build, a conservatory in the way, a neighbour’s land to cross.
• The roof covering — slate and old clay tile take more care, and more boards, than modern concrete tile.
• The work — a rebuild or removal needs a heavier duty and a loading point; a repoint does not.
• A highway licence — if the scaffold is on the footway.
• The hire period.

As a guide, published UK price guides put chimney-only scaffolding at roughly £400 to £900 for a straightforward stack with a standard hire period, with London and the south east, three-storey houses, central stacks and complex roofs above that. Treat that as a budget figure, not a quote. Send us the address and a photograph of the stack, and we will give you a fixed written price that states the hire period, what is included and what is not.

Where we put up chimney scaffolds

• Oxfordshire — Oxford, Kidlington, Bicester, Witney, Banbury, Abingdon, Didcot, Thame, Wallingford and the villages.
• Buckinghamshire — Aylesbury, High Wycombe, Amersham, Beaconsfield, Gerrards Cross, Buckingham and Milton Keynes.
• Bedfordshire — Bedford, Luton, Dunstable, Leighton Buzzard and Biggleswade.
• South Northamptonshire — Brackley, Towcester, Brixworth and the villages.

For other domestic work see domestic scaffolding, and for a re-roof that needs weather protection, temporary roofs.

Chimney scaffolding questions