Most calls about a bollard in front of someone's own house come after something has happened. That was the case here too: the customer's car had been stolen from the driveway. The decision in favour of a retractable bollard was made quickly after that – the only open question was whether one could be installed in this driveway at all. The access in front of the house has a gradient of over 15 per cent, and a bollard must stand exactly vertical.
Why a retractable bollard must stand plumb
Inside the bollard, a piston rod moves up and down in plain bearing bushes, and at the top sits a metal scraper that keeps dirt and water off the rod. This only works if the cylinder is vertical. If it is skewed, the bushes are loaded on one side, the scraper does not seal all the way round, and the system runs into wear. That is why we set every bollard plumb with a spirit level in compacted sand – regardless of how the surface above it runs.
With a 15 per cent gradient, that is exactly the problem: over one metre of length, the driveway drops 15 centimetres. Across the bollard's diameter of 27 centimetres, that means a height difference of around 4 centimetres between the uphill and downhill side. The bollard collar sits horizontally, the paving around it slopes. This cannot be solved neatly with the large-format slabs of the driveway – on one side the slab would protrude above the collar, on the other there would be an edge to trip over.
The solution: a square of natural stone setts
Instead of running the slabs right up to the bollard, we laid a square of small natural stone setts around the collar. The small stones can be laid with infinite adjustment: slightly higher on the downhill side, slightly lower on the uphill side, so that the height difference runs out over a few centimetres. The transition from the sloping surface to the horizontal bollard collar is smooth, nothing protrudes, nothing forms a trip edge – and visually the dark small setts look like a deliberate frame around the stainless steel.
The photo shows exactly this: large-format slabs in the driveway, the drainage channel in front, and in the middle the raised bollard with its frame of small setts. If you do not know about the gradient, you cannot tell from the result how much height was compensated here. We used the same technique – bollard plumb in sand, adjustment with small stones – at the courtyard entrance with small granite setts.
Water runs downhill – and the bollard is at the bottom
A gradient has a second consequence: when it rains, the water from the whole driveway runs towards the bollard before it reaches the channel. For a bollard with a motor, circuit board and limit switches in its housing, this is a critical location – such systems need a drain and often a heater, and both have to work for years. With our bollards, the only thing in the ground is a stainless steel cylinder. It is sealed to IP69 and can stand completely under water without being damaged. The compressor, valve and control unit sit protected in the house.
- Stainless steel V4A (1.4571): 6 mm wall thickness, brushed – no rust even after years of road salt and rain.
- No electronics in the ground: nothing that can get damp, overheat or freeze.
- Seals down to −35 °C: piston rod with metal scraper and grease chamber, designed for frost and wet.
- Low-maintenance: if a valve or the compressor needs replacing after years, this is done in the house on a quick-release coupling – the paving stays closed.
Why we work exclusively with compressed air and what electric spindles and hydraulics in the ground do differently is explained in our comparison of bollard drives.
Three radio transmitters – one for every key ring
The system is operated by radio. The customer received three radio transmitters so that everyone in the household has one on their key ring and nobody has to wait for anyone else. One press of a button from the car, the bollard lowers in a few seconds, you drive in, a second press – and the bollard is up again. The receiver sits in the radio control unit in the house; further transmitters can be paired there at any time, for example for a new family member or a second car.
Sabotage protection: the bollard stays up
Anyone who protects their car with a bollard after a theft rightly asks what happens if someone comes with tools. That is why our bollards have a mechanical height lock: as soon as the bollard is raised, a locking bolt engages. The bollard can then not be pushed down – not even with the weight of a vehicle or with a lever. And even if someone cuts the compressed air hoses, the air escapes, but the bolt holds and the driveway stays closed. A bollard that sinks when air is lost would be worthless for this purpose.
What the system cost
The bollard is our 160-kilogram standard model and cost around 3,000 euros, plus the three radio transmitters. Measured against the value of a vehicle, the insurance excess and the premium that rises after a theft, that is a manageable sum – and the system has been in operation since 2017. How keyless-go thefts work and why a bollard helps where a gate often does not close in time can be read on our page on keyless-go theft.
Does your driveway have a gradient?
Gradients, bends, narrow accesses or a channel exactly where the bollard should go – we know driveways like these. Send us a photo of your driveway via WhatsApp to +49 172 4544485 or call us on +49 40 226390411. We will tell you whether and where the bollard can stand, how the cable bundle gets into the house and what the system costs for your driveway. You will find all models in our overview retractable bollards made of stainless steel V4A.
