Documenting access dimensions before anyone quotes

A machine that cannot get in is a mobilisation charge for nothing. Six measurements, taken with a tape in twenty minutes, let every bidder tell you in advance whether their equipment fits — which is information no photograph provides.

Published by the Land Clearing Authority editorial team · Last revised 2026-07-29 · Editorial policy · Corrections

Who this is for

Owners whose access runs through a gate, a lane, or between structures
Anyone with a bridge, culvert, or cattle grid on the route
People requesting quotes before a contractor has visited

The short answer

Measure at the obstruction, not at the opening. A gateway is as wide as the gap between the posts, and a lane is as wide as the point where a tree leans into it.

The six measurements: narrowest horizontal width, lowest overhead clearance, tightest turning point, steepest gradient on the route, any crossing structure, and the total distance from the road to the work area.

Record each with its location, so a contractor knows where the constraint is as well as what it is. "Nine feet at the gate, forty feet in from the road" is actionable; "the gate is a bit narrow" is not.

Then state what you cannot establish — usually the load capacity of a culvert or bridge, which you cannot determine by looking and which is the highest-consequence unknown on most residential access.

What changes the answer

Whether obstructions can be temporarily removed
How the route behaves in wet conditions
Whether a second entry point exists
What has to travel the route besides the machine
Whether the surface has to survive the work in usable condition

The six measurements

Take each at the tightest point rather than at a representative one. The route is only as passable as its worst constraint.

What to measure and where
Measurement	Take it at	Why it matters
Narrowest width	Between the actual obstructions	Decides which machines can pass at all
Lowest overhead clearance	Under branches, wires, or a structure	A loaded transport is taller than a machine
Tightest turn	Any corner or entrance	A long transport needs more room than a machine
Steepest gradient	The worst pitch on the route	Affects loaded vehicles and traction
Crossing structures	Each culvert, bridge, or grid	Load capacity is usually unknown
Total distance	Road to work area	Affects travel time and material handling

How to measure a width that means something

The commonest error is measuring the wrong thing, and it is an easy one to make.

A gateway with posts, a hedge growing inwards, and a mailbox on one side is not as wide as the drive. Measure between whatever physically protrudes at the height a machine or transport passes — which may not be at ground level. A gate post is narrow at the base and a hedge is widest at the middle.

Do the same overhead. Branches hang lowest when wet or in full leaf, so a measurement taken in February may not hold in July. Note when you measured, and note anything that will have grown by the work date.

Then check whether the constraint is removable. A gate that can come off its hinges, a branch that can be cut, a post that can be temporarily taken out — those change the answer entirely and are worth identifying.

The crossing structures you cannot assess

A culvert under a drive, a small bridge over a ditch, a cattle grid — each carries whatever crosses it, and none of them tells you what it can carry.

What you can record: material and diameter where the ends are visible, whether either end is deformed or silted, how much cover sits above it, and any visible cracking or subsidence in the surface above.

What you cannot establish is capacity. Say so, explicitly, and let the contractor plan around an unknown rather than driving over an assumption. Where the structure serves a public road, the authority owning that road may hold records or have requirements about loads crossing it.

Recording it usefully

A short structured note, sent with your photographs, does the work.

Each measurement, with the location described from the road
The date taken, and anything that will have grown since
Which constraints could be temporarily removed, and by whom
How the route behaves after heavy rain
Every crossing structure, with what you could and could not establish
Whether a second entry point exists, even a rough one
What condition the route needs to be in when the work finishes

Wet-weather behaviour, which is a dimension too

A route that is nine feet wide and firm in August may be nine feet wide and impassable in March, and the second fact matters as much as the first.

Walk it after heavy rain and note where water stands, where the surface softens, and whether any part becomes a channel. Photograph it. That single set of images tells a contractor more about your access than any dry-weather measurement.

It also identifies where ground protection would be needed, which is a real line item and one you would rather see in a quote than discover as a variation.

What the measurements are for

Two things, and the second is the one owners underestimate.

The first is elimination: a contractor whose machine will not fit can say so before travelling, which saves both parties a wasted visit.

The second is method. A contractor who knows the route is constrained will propose a different approach — a smaller machine, a route improvement priced as its own item, matting over the soft section, or unloading at a different entrance. That proposal is the useful output, and it only arrives if the constraint is visible before the quote is written.

What drives the cost

Cost drivers on this kind of project
Driver	Effect
Narrowest width on the route	Constrains machine choice and therefore output
Route improvement required	Widening or surfacing is clearing and earthworks in its own right
Ground protection	Matting or plates over soft sections and crossings
Unknown crossing capacity	May force an alternative route or bridging arrangement
Total route distance	Longer routes add travel time on every material movement

Common mistakes

Measuring the gateway rather than the gap between the posts
Measuring overhead clearance in leaf-off conditions for summer work
Measuring for the machine and not for the transport delivering it
Never mentioning the culvert because it has always been fine
Assessing the route only in dry conditions

Questions to ask a contractor

Does the narrowest point work for the machine and the transport?
What would you need if the culvert capacity stays unknown?
Which of my constraints would you want removed before you arrive?
Would you unload somewhere other than the end of the drive?
What ground protection does this route need, and is it in the price?

What to do next

Take the six measurements at the tightest point of each
Walk and photograph the route after heavy rain
Record what you could not establish, particularly crossing capacity
Send the same access note to every bidder with your photographs

Questions people actually ask

How wide does access need to be?

It depends entirely on the machine and the transport, so the useful move is to supply your figure and let each contractor tell you whether their equipment fits rather than working from a general number.

What if my access is too narrow for anything?

The options are widening the route, a smaller machine at lower output, unloading elsewhere, or access from adjoining land. All four are real and all four are cheaper to consider before a machine arrives.

Can I find out what my culvert can carry?

Often not with certainty. Record material, diameter, condition, and cover, ask any authority that owns the road it serves, and otherwise treat capacity as an unknown to plan around rather than a risk to take.

Should I improve the access before quoting?

Usually better to document it and let bidders tell you what they need. Improvements made before anyone has assessed the route can turn out to be the wrong ones.