Crane oversailing and third party land

A crane oversailing agreement is a private contract with a neighbouring owner, and no planning permission, condition or council officer can supply one for you. Swinging a jib through someone else's airspace is trespass, and the courts have granted injunctions to stop it. On a constrained urban site that makes the neighbour holding the airspace a party whose agreement sits on the critical path, usually several months before anyone books a crane.

Why oversailing is a private law problem

Airspace above land belongs with the land, at least to the height needed for its ordinary use and enjoyment. A tower crane jib passing over a neighbouring roof at fifteen metres is inside that zone, and the remedy an owner can ask for is an injunction rather than damages.

Two older cases set the position that the construction industry still works to. In one, a court granted an injunction against a contractor whose crane swung over adjoining land, and in the other the injunction was suspended until the works were due to finish, which gave the developer time but confirmed the principle. The practical lesson from both is that a neighbour who wants to stop you can, and that the price of agreement rises once the crane is on site.

Out of service conditions catch people out. A tower crane is normally left to weathervane when not working, so the jib rotates freely with the wind and will pass over whatever is around it. An agreement that permits oversailing only during lifting operations does not cover that, and the drafting has to deal with it explicitly.

What a planning condition can and cannot do

A planning permission authorises development. It confers no rights over land you do not control, and the standard ownership certificates on the application form are notification requirements rather than grants of access.

Conditions still touch the subject constantly. Most urban permissions carry a construction management or logistics plan condition requiring crane positions, oversailing extents, delivery routes, hours and wheel washing to be approved before work starts. A council can refuse to discharge that condition if the submitted plan shows a crane sweeping over land you have no right to use, which is how a private law problem turns into a planning delay. The distinction between the two is set out further in the piece on crane oversail and what planning permission does not grant.

Some conditions go further and require evidence that third party agreements are in place before demolition begins. Read the wording rather than assuming the standard form.

Negotiating the licence, and when to start

Start early enough that you still have alternatives, because the negotiation is only as balanced as your fallback. Six months before the crane is needed is not generous on a site with several adjoining owners, particularly where one of them is a managing agent acting for a residential block with a leasehold structure and no obvious decision maker.

Identify who actually owns the airspace. On a block of flats it may be the freeholder rather than the residents' association, and on commercial property the tenant's lease may or may not include the roof. Land Registry title plans and register entries answer this in a day and save weeks of talking to the wrong party.

Then work out what the neighbour needs. Frequently it is not money. It is certainty that their roof plant will not be damaged, that their fire escape stays usable, that their tenants are not disturbed at night, and that somebody will pay to put things right if a load is dropped. A schedule of condition prepared before works start, with photographs and a survey, answers most of that on its own, and a structural survey of the adjoining property is worth commissioning even where nobody has asked for one.

What the licence should actually say

A one page letter agreement is where disputes come from. The terms below are the ones that matter in practice.

• The precise extent of the permitted oversail, shown on a plan with the crane centre, radius and out of service swing circle marked.
• Minimum clearance above the neighbour's highest structure, roof plant and any flue.
• Whether loads may pass over the land at all, and if so which loads, or whether only the unloaded jib may cross.
• Hours during which slewing over the land is allowed, and what happens out of hours and in out of service mode.
• The duration of the licence and what happens if the programme slips.
• Insurance levels, an indemnity, and a named contact for incidents.
• A schedule of condition agreed before works start and a repair obligation afterwards.
• Access rights for inspection, and rights to survey the neighbour's roof if needed.
• The fee, and whether it is a lump sum or a monthly licence payment.

Lifting operations themselves sit under separate duties. The lifting regulations and the construction design and management regime govern planning of lifts, competence and supervision, and none of that is displaced by a licence from a neighbour.

The cost of being refused

A refusal rarely stops a scheme. It changes the method, and the change is expensive.

Without an oversail licence the options narrow to a luffing jib crane that can work with a much tighter swept area, a crane positioned so the out of service circle stays within the site, mobile cranes brought in for individual lifts, or a change of construction method towards precast or volumetric units that need fewer and shorter lifts. Each carries cost and programme consequences, and each has knock-on effects on the site set-up, the hoarding line and the delivery schedule.

There is one other consequence worth planning for. A crane repositioned inside the site footprint takes space away from material storage and welfare, which pushes deliveries up in frequency, which is the thing highways officers and neighbours object to most. The logistics plan then has to work harder.

Designing the oversail out

The cheapest oversail agreement is the one you do not need, and the decisions that make it unnecessary are taken at design stage rather than on site.

Positioning the core centrally, keeping the tallest element away from the tightest boundary, choosing a frame that suits a luffing jib, and sequencing the build so the constrained edge is completed first all reduce exposure. So does thinking about the demolition phase, which is where the reach demands are often greatest and where the neighbours are most alert. Where demolition involves older fabric, the survey work has to be done before anyone prices the method, and the sequence in the note on asbestos surveys before demolition or refurbishment sits ahead of the logistics work rather than alongside it.

Basement schemes deserve particular attention, because the excavation phase brings party wall notices, temporary works and neighbour anxiety at the same moment the crane arrives. Where a basement impact assessment is required, the construction sequence described in it should be the same sequence the logistics plan assumes.

What belongs in the construction logistics plan

Councils vary in what they call the document and in how much detail they want. The content that answers the question is consistent.

1. A site set-up plan showing the crane position, working radius, out of service swing circle, hoarding line, gates, welfare and storage.
2. Identification of every third party landowner whose airspace or land is affected, with the status of each agreement.
3. Clearance heights over adjoining structures, with the neighbouring roof levels surveyed rather than scaled.
4. Working hours for lifting, separately from general working hours, and the arrangements out of hours.
5. Delivery routing, vehicle sizes, booking system and the number of movements at peak.
6. Erection and dismantling of the crane, including any road closure or temporary traffic order needed, which has its own lead time.
7. Any aerodrome safeguarding, railway or waterway consultation triggered by the crane height or position.

Say plainly where an agreement is not yet in place and what the fallback method is. Officers are used to that, and a plan that admits an open point with a named alternative is more likely to be approved than one that quietly assumes rights the applicant does not hold.

PlanScope drafts construction management and logistics documents from your site details, flagging the third party agreements and survey facts that have to be confirmed before submission. Enter your postcode to see what a constrained urban site is likely to need.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.