Two schemes with the same drawings can cost materially different amounts because one has a yard and the other has a pavement. That difference lives in the preliminaries, and the preliminaries are the part of a tender that gets the least scrutiny. As quantity surveyors in London we spend a disproportionate amount of time there, because that is where the money is.
Logistics is not an overhead to be trimmed at the end. On a city site it is a method statement with a price attached, and it should be priced before the contract rather than argued about during it.
Access decides the method
The question is not whether a lorry can reach the site. It is what can be brought in, how often, at what hour and with how many people standing in the road to make it safe. A single gate onto a busy street with a timed delivery window produces a different build from an open compound, even where the building is identical.
That constraint then runs backwards into design. Panel sizes, pour volumes and plant selection all follow from what can physically arrive, which is why access belongs in the cost plan at the start rather than in the contractor's problem list later.
Craneage and oversailing
A crane that has to stay within the site boundary is a different crane from one permitted to oversail a neighbour, and permission to oversail is a negotiation with the adjoining owner rather than a right. Where it is refused, the method changes and so does the price.
Mobile cranes on a public road bring road closures, licences and a cost per lift that makes the number of lifts a commercial question rather than a technical one.
Storage you do not have
With no space to store materials, the project moves to just in time delivery. That reduces the risk of damage and theft and increases the risk of standing labour when a delivery is late. It also means the contractor is carrying a logistics overhead every week of the programme.
Just in time working interacts with payment. If materials are not on site, they are not in the valuation, which changes the contractor's cash position and sometimes their behaviour. That link is covered in paying for work actually in place.
Working hours belong to the borough
Permitted working hours, noisy works restrictions and consent for out of hours operations are set locally and vary between boroughs. A programme written on standard hours may not survive contact with the specific authority, and the gap shows up as an extension of time claim rather than as a priced item.
Where the site sits near a school, a hospital or a residential street, expect further conditions. These need checking with the council that actually applies, not inferred from another scheme.
Protection, pavements and the public
Hoarding, gantries, pavement licences, temporary pedestrian routes and traffic management are not incidental. On a scheme fronting a busy footway they can be a significant proportion of the preliminaries, and they run for the whole programme rather than for the week the work happens.
Because they run for the duration, every week of delay costs them again. That is why a logistics heavy site punishes programme slippage more than an open site does.
Welfare, waste and the vertical journey
Site accommodation has to go somewhere. Where there is no ground to put it on, it goes on a gantry, on the roof of a lower storey, or it is rented off site and walked to. Each of those is a different number and each one has to be maintained for the whole programme.
Waste works the same way in reverse. Segregated waste needs space for more than one container, and where there is space for one, the cost moves from skip hire to a managed collection with a shorter cycle.
On a tall building the vertical journey becomes its own item. A hoist, the power to run it, the time every operative spends in it and the sequencing of material movements against people movements all belong in the preliminaries rather than in the trades.
Neighbours, noise and the complaint that stops work
On a constrained site the people living around it are close enough to be affected daily. Complaints lead to conditions, and conditions lead to restricted hours or restricted methods, which lead to a longer programme.
Contractors experienced in this environment budget for liaison: a named contact, a letter drop before noisy phases and a record of what was agreed. It is a small line that prevents a large one.
How to price it rather than discover it
Ask for the preliminaries to be priced against a stated logistics method, not as a percentage. Ask what the method assumes about delivery hours, crane position, storage and pavement occupation. Then check those assumptions against the borough and the neighbours before the contract is signed.
Where the assumptions turn out to be wrong afterwards, you are negotiating from behind. Where they are written down beforehand, the risk sits with whoever accepted it, which is the entire purpose of writing it down. See tendering and procurement.
There is also a simple test you can apply to any tender on a constrained site. Ask each contractor to describe, in a paragraph, how the heaviest single item reaches its final position. The answers will differ, and the differences explain most of the variation between their preliminaries.
A contractor who cannot answer that question has not thought about your site. A contractor whose answer requires something you have not secured, such as oversailing rights or a road closure, has given you a price for a project that does not yet exist.
Pricing a constrained site?
Tell us where the site is, what the access looks like and what stage the design has reached. We will set out what the logistics are likely to carry and what has to be confirmed with the borough.