Question 1

Can my driveway take a heavy vehicle?

Accepted Answer

Only if it was built for one. A drive designed for a car has a sub-base sized for a car, and a motorhome, horsebox or delivery lorry puts several times that load through a much smaller contact area. Turning heavy vehicles are worse still, because a turning wheel shears the surface rather than just pressing on it. The design question is about load spread rather than total weight. A driveway takes a concentrated wheel load and distributes it through the surface and the sub-base until the pressure reaching the soil is manageable. Double the axle load and the sub-base has to be substantially thicker to do the same job — it is not a marginal adjustment, and it is decided before the drive is built rather than afterwards. Turning is the part people underestimate. A wheel rolling straight presses down; a wheel turning on the spot applies a horizontal shear force into the surface. That is why the entrances and turning circles of car parks fail long before the parking bays, and why a delivery lorry manoeuvring on a domestic drive does more damage in one visit than a hundred cars driving straight over it. The good news is that this is easy to design for if it is known in advance. A thicker sub-base, a geogrid over softer ground, a stiffer surface where the turning happens — concrete or a stone mastic asphalt at the pinch point rather than the same specification everywhere — and heavier edge restraint all address it, and none of it is dramatic when it is designed in. Retrofitting it means rebuilding. There are two specific things to check on an existing drive, and both are quick. Inspection chamber covers: a light pedestrian-duty cover, which is what many gardens and paths have, will crack under a car and certainly under a lorry. Covers are classified under BS EN 124 and the class is a specification to state rather than assume. And the entrance apron, which takes the worst of every turning wheel. The honest answer for a lot of existing domestic drives is that they will take an occasional heavy vehicle and will show it. A skip lorry once is usually survivable; a motorhome parked in the same spot every week is not, and neither is a delivery vehicle turning on the drive weekly. If a heavy vehicle is part of the plan, say so at the quote stage — it changes the specification, and the difference in cost at construction is far smaller than the cost of rebuilding.

Question 2

Will my drive take a motorhome?

Accepted Answer

Only if it was built for one. A drive designed for a car has a sub-base sized for a car, and a motorhome, horsebox or delivery lorry puts several times that load through a much smaller contact area. Turning heavy vehicles are worse still, because a turning wheel shears the surface rather than just pressing on it. The design question is about load spread rather than total weight. A driveway takes a concentrated wheel load and distributes it through the surface and the sub-base until the pressure reaching the soil is manageable. Double the axle load and the sub-base has to be substantially thicker to do the same job — it is not a marginal adjustment, and it is decided before the drive is built rather than afterwards. Turning is the part people underestimate. A wheel rolling straight presses down; a wheel turning on the spot applies a horizontal shear force into the surface. That is why the entrances and turning circles of car parks fail long before the parking bays, and why a delivery lorry manoeuvring on a domestic drive does more damage in one visit than a hundred cars driving straight over it. The good news is that this is easy to design for if it is known in advance. A thicker sub-base, a geogrid over softer ground, a stiffer surface where the turning happens — concrete or a stone mastic asphalt at the pinch point rather than the same specification everywhere — and heavier edge restraint all address it, and none of it is dramatic when it is designed in. Retrofitting it means rebuilding. There are two specific things to check on an existing drive, and both are quick. Inspection chamber covers: a light pedestrian-duty cover, which is what many gardens and paths have, will crack under a car and certainly under a lorry. Covers are classified under BS EN 124 and the class is a specification to state rather than assume. And the entrance apron, which takes the worst of every turning wheel. The honest answer for a lot of existing domestic drives is that they will take an occasional heavy vehicle and will show it. A skip lorry once is usually survivable; a motorhome parked in the same spot every week is not, and neither is a delivery vehicle turning on the drive weekly. If a heavy vehicle is part of the plan, say so at the quote stage — it changes the specification, and the difference in cost at construction is far smaller than the cost of rebuilding.

Question 3

Can a skip lorry park on my driveway?

Accepted Answer

Only if it was built for one. A drive designed for a car has a sub-base sized for a car, and a motorhome, horsebox or delivery lorry puts several times that load through a much smaller contact area. Turning heavy vehicles are worse still, because a turning wheel shears the surface rather than just pressing on it. The design question is about load spread rather than total weight. A driveway takes a concentrated wheel load and distributes it through the surface and the sub-base until the pressure reaching the soil is manageable. Double the axle load and the sub-base has to be substantially thicker to do the same job — it is not a marginal adjustment, and it is decided before the drive is built rather than afterwards. Turning is the part people underestimate. A wheel rolling straight presses down; a wheel turning on the spot applies a horizontal shear force into the surface. That is why the entrances and turning circles of car parks fail long before the parking bays, and why a delivery lorry manoeuvring on a domestic drive does more damage in one visit than a hundred cars driving straight over it. The good news is that this is easy to design for if it is known in advance. A thicker sub-base, a geogrid over softer ground, a stiffer surface where the turning happens — concrete or a stone mastic asphalt at the pinch point rather than the same specification everywhere — and heavier edge restraint all address it, and none of it is dramatic when it is designed in. Retrofitting it means rebuilding. There are two specific things to check on an existing drive, and both are quick. Inspection chamber covers: a light pedestrian-duty cover, which is what many gardens and paths have, will crack under a car and certainly under a lorry. Covers are classified under BS EN 124 and the class is a specification to state rather than assume. And the entrance apron, which takes the worst of every turning wheel. The honest answer for a lot of existing domestic drives is that they will take an occasional heavy vehicle and will show it. A skip lorry once is usually survivable; a motorhome parked in the same spot every week is not, and neither is a delivery vehicle turning on the drive weekly. If a heavy vehicle is part of the plan, say so at the quote stage — it changes the specification, and the difference in cost at construction is far smaller than the cost of rebuilding.

Can my driveway take a heavy vehicle?

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