Robot Vacuums and UK Door Thresholds: How High They Climb

Why British homes trip up robot vacuums

A robot vacuum is built for a flat floor, and a British house rarely has one. The usual culprit is the door bar. That's the metal or wooden strip in a doorway that covers the join where carpet meets laminate or tile. It sits higher than the floor on both sides. Then there's the threshold strip at the back door, the step down into a kitchen extension, a fringed rug and the radiator pipes along the skirting. Add them all up and the robot has an obstacle course to get round, rather than a floor to clean.

The heights involved are small. Household thresholds run anywhere from 6 mm to over 25 mm, according to Ecovacs's UK guide. An accessible threshold should rise no more than 15 mm. That's from the UK accessibility guidance cited in eufy's threshold article. A recent build tends to be within what a robot can manage. An older house with a step between rooms isn't.

How high each maker says its robots can climb

Every maker on our robot vacuums list answers the question somewhere, though rarely on the product page. Here's what they say about our seven picks.

eufy X10 Pro Omni: 20 mm. Its manual says the robot "may climb on top of objects less than 0.79 in / 20 mm in height". It's phrased as a warning, but it's the figure the machine is built to.
roborock Qrevo Edge 2 and Qrevo S Pro: 2 cm, with a catch. All roborock robots except the old S4 can climb 2 cm (0.79 in), according to the company's support answer. But that answer names only earlier models. Neither the Qrevo S Pro's UK page nor its manual gives a figure of its own, and the Qrevo Edge 2's listing gives none either.
TP-Link Tapo RV30 Max Plus: 22 mm. Its "barrier-cross height" is 22 mm (0.87 in), according to Tapo's UK page. That's the highest published figure among our picks.
eufy Omni C20 and eufy C10: not published. Neither product page gives a climb height. Both advise securing curled or thin carpet edges, and drawing no-go zones around thick carpet. A no-go zone is an area you mark in the app for the robot to stay out of.

Twenty millimetres is where the industry has settled. A standard robot typically clears up to 20 mm, Ecovacs says. The exceptions are the newer lifting-chassis machines, which raise their body up on the wheels when they reach a step. On the Qrevo Curv 2 Pro, roborock claims its AdaptiLift chassis can cross 4 cm double-layer thresholds (ones with two levels). For its Omni S2, eufy claims 3.5 cm for a single threshold and 4.2 cm for a double. Neither is on our list.

Wheels, clearance and the shape of the strip

Three things decide whether a robot gets over a strip. The first is the drive wheels. Bigger wheels with a textured or rubberised tread bite on the edge and lift the body. A small smooth wheel spins instead. The second is the motor, which needs the torque (turning force) to keep pushing once the nose is tilted upward. The third is ground clearance, the gap between the floor and the robot's underside. If the strip is taller than that gap, the belly lands on it, the wheels lose contact and the robot is beached.

Sprung wheels drop below the body to keep their grip as the chassis tips. A lifting chassis pushes the whole body up on them.

Clearance is also why the figure tops out at 20 mm. A robot raised high enough to clear a 40 mm step all the time would be too tall to get under a sofa. So the lifting designs stay low on the flat, and jack the body up only when a sensor sees a step.

The shape of the strip matters as much as its height. Rounded or bevelled (sloped) edges on room dividers are typically easier to climb than square ones, Ecovacs's guide notes. That's because the wheel rolls up a slope instead of hitting a wall. So the same 20 mm can be an easy climb on a sloped aluminium door bar, and a dead stop on a square-edged hardwood threshold.

What to do about a threshold it can't climb

Here are four ways round it.

A ramp. Both eufy and Ecovacs suggest one. It can be rubber, aluminium or wood, a 3D-printed wedge, or a foam wedge you can move without making permanent changes. Aim for a gentle slope, a longer ramp for a smoother transition and an anti-slip covering, eufy advises.
A low-pile rug. This is Ecovacs's other workaround. A thin rug laid across a threshold between two hard floors bridges the edge.
A no-go zone. If the robot maps your home, you can wall a step off in its app. The eufy UK page for the C10 suggests one for dark-coloured stairs, and for carpets thicker than 25 mm. The roborock Qrevo S Pro manual suggests the same for carpet when mopping.
A second unit. If the step is a full stair, the answer is one robot per floor. The eufy C10 is the natural upstairs machine. It's the vacuum-only pick, with no water tanks, and eufy says it goes eight weeks between bag changes.

Rugs and tassels

Carpet detection. A sensor on the underside notices when the surface changes. On a vacuum, that triggers carpet boost, which turns the suction up. The RV30 Max Plus increases suction on carpet, Tapo's page says. On a mopping robot, the sensor makes the mops lift, or makes the robot back off. The eufy X10 Pro Omni lifts its mops 12 mm. The roborock Qrevo Edge 2's listing says it adjusts to carpet but gives no lift figure. The Tapo avoids carpet altogether in mopping mode.

The edge. The rug that catches is a thin one with a loose edge, because the brush grabs the underside. For the C10, eufy's advice is to fix the edges of thin carpets so they don't get tangled. For the Omni C20, it's to flatten or secure curled edges.

Tassels. The manual for the eufy X10 Pro Omni says to fold tasselled edges underneath to prevent tangling. It also says to avoid high-pile rugs (the ones with long fibres) or rugs thicker than 18 mm. The roborock picks have anti-tangle brushes, but their listings say those are designed for hair. No maker here claims they cope with a fringe. So fold it under, or draw a no-go zone along the edge of the rug.

Which of our picks fits which home

Carpet and hard floors, with ordinary door bars. The eufy X10 Pro Omni. It has a published 20 mm climbing height, carpet detection and a 12 mm mop lift, and its station washes and dries the mops. If your door bars are under 20 mm and bevelled, it crosses them and keeps the carpet dry.

The same house, with a dog that sheds. The roborock Qrevo Edge 2 has a dual anti-tangle brush system and an all-in-one dock that washes the mops in hot water, per its listing. Its body is 3.14 inches tall, so it goes under more furniture. But it publishes no mop-lift figure, so on carpet, draw the no-go zone. For the door bars, it gets roborock's support figure of 2 cm, with the catch above.

A larger house with fringed rugs. The roborock Qrevo S Pro pairs the most refined mapping on our list with anti-tangle brushes. It gets roborock's support figure of 2 cm.

Hard floors throughout. The eufy Omni C20 does the all-in-one job, with sixty days between bag changes. But eufy publishes no climb height for it, so measure your door bars first. The TP-Link Tapo RV30 Max Plus has the highest published figure of the seven, at 22 mm. It has LiDAR mapping (a laser sensor that maps the room) and an auto-empty dock, and it stays off carpet in mopping mode. Its stated suction is the lowest here.

Carpet throughout, or the upstairs unit. The eufy C10 is vacuum only, with a self-emptying dock, and eufy says it goes eight weeks between bag changes. There are no tanks to fill and nothing to mop. It has no published climb height either.

An old house with a step between rooms. None of the seven. A step of 30 mm or more is beyond every figure above. The answer is a ramp, a no-go zone or a lifting-chassis machine.

How high a threshold can a robot vacuum go over?

Around 20 mm for a standard robot. That's where the makers' figures cluster: 20 mm from eufy for the X10 Pro Omni, 2 cm from roborock, 22 mm from Tapo and 1.6 cm from iRobot for every Roomba. Lifting-chassis machines claim 3.5 to 4 cm and more, but none of them is among our seven. For the Omni C28, eufy adds "under ideal conditions" to its 2 cm figure, and that applies to all of them. The ideal condition is a bevelled edge on a hard floor.

Can a robot vacuum do stairs?

No. None of the seven on our list climbs a stair. Instead, they have anti-drop sensors, which stop the robot at an edge. These keep the X10 Pro Omni from tumbling down stairs in most cases, eufy's manual says. But they're less effective when dirty, or on carpeted or reflective floors. The roborock manual says not to leave shoes or mats near stairs, because the robot may fall. So a two-storey house needs a second robot, or one you carry up that stores more than one map. Our buying guide says the same.

Do robot vacuums damage door thresholds or rugs?

The threshold is safe. None of the makers' guides mentions damage to a door bar. Rugs are a risk to the robot, and the robot is a risk to rugs. A fringe or a loose edge winds into the brush, and the robot stalls or drags the rug. So fold tassels under and fix thin edges. A mopping robot also leaves a rug damp unless the mops lift clear. That's why eufy's manual keeps the X10 Pro Omni off rugs thicker than 18 mm.