Robot Vacuums and UK Door Thresholds: How High They Climb

Why British homes trip robot vacuums

A robot vacuum is built for a flat floor, and a British house rarely offers one. The usual culprit is the door bar: the metal or wooden strip that covers the join where carpet meets laminate or tile in a doorway and sits proud of both. Add the threshold strip at the back door, the step down into a kitchen extension, a fringed rug and the radiator pipes along the skirting, and the robot has a course to complete rather than a floor to clean.

The heights are small. Ecovacs's UK guide puts household thresholds anywhere from 6 mm to over 25 mm, and the UK accessibility guidance that eufy's threshold article cites treats 15 mm as the maximum upstand for an accessible threshold. A recent build tends to sit inside what a robot can manage; an older house with a step between rooms does not.

What the makers publish

Every maker on our robot vacuums list answers the question somewhere, though rarely on the product page. For our seven picks:

eufy X10 Pro Omni: 20 mm. eufy's manual says the robot "may climb on top of objects less than 0.79 in / 20 mm in height". It is phrased as a warning, but it is the figure the machine is built to.
iRobot Roomba Plus 415: 1.6 cm. iRobot's support site gives one figure for the whole range: the maximum threshold all Roomba models can transition over during a clean is ⅝ in (1.6 cm). Nothing separate is published for the Plus 415.
roborock Qrevo S Pro and Qrevo: 2 cm, with a caveat. roborock's support answer puts the climbing ability of its robots at 2 cm (0.79 in), the old S4 excepted, but it names only earlier models, and neither the Qrevo S Pro's UK page nor its manual gives a figure of its own.
TP-Link Tapo RV30 Max Plus: 22 mm. Tapo's UK page lists a "barrier-cross height" of 22 mm (0.87 in), 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.

Twenty millimetres is where the industry has settled; Ecovacs says a standard robot typically clears up to 20 mm. The exceptions are the new lifting-chassis machines, which raise the body on the wheels at a step: roborock claims 4 cm double-layer thresholds for the AdaptiLift chassis on its Qrevo Curv 2 Pro, and eufy 3.5 cm single and 4.2 cm double for its Omni S2. Neither is on our list.

The physics: wheels, clearance and the shape of the strip

Three things decide whether a robot gets over a strip. The drive wheels: bigger wheels with a textured or rubberised tread bite on the edge and lift the body, where a small smooth wheel spins. The motor, which needs the torque to keep pushing once the nose is tilted upward. And ground clearance, the gap between floor and 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 stalls 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. Ecovacs's guide notes that rounded or bevelled edges on room dividers are typically easier to climb than square ones, because the wheel rolls up a slope instead of hitting a wall. 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 cannot climb

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

Rugs and tassels

Carpet detection. A sensor on the underside registers the change of surface. On a vacuum it triggers carpet boost: Tapo's page says the RV30 Max Plus increases suction on carpet. On a mopping robot it triggers the lift or the retreat: the eufy X10 Pro Omni lifts its mops 12 mm, the Roomba Plus 415 lifts its pads 10 mm, and the Tapo avoids carpet altogether in mopping mode.

The edge. A thin rug with a loose edge is the one that catches: the brush grabs the underside. eufy's advice for the C10 is to fix the edges of thin carpets to prevent entanglement; for the Omni C20, to flatten or secure curled edges.

Tassels. eufy's X10 Pro Omni manual says to fold tasselled edges underneath to prevent tangling, and to avoid high-pile rugs or rugs thicker than 18 mm. The anti-tangle brushes on the roborock picks are designed for hair, per their listings, and no maker here claims they cope with a fringe. Fold it under, or draw the no-go zone along the edge of the rug.

Which of our picks fits which home

Carpet and hard floors, ordinary door bars. The eufy X10 Pro Omni: a published 20 mm object height, carpet detection, a 12 mm mop lift and a station that washes and dries the mops. If the door bars are under 20 mm and bevelled, this crosses them and keeps the carpet dry.

The same house with a shedding dog. The iRobot Roomba Plus 415 has tangle-free rubber brushes and an all-in-one dock with a stated 90 days between bag changes, but its mops lift 10 mm and iRobot's blanket figure is 1.6 cm, the lowest published number here. A 20 mm door bar is above it.

A larger house with fringed rugs. The roborock Qrevo S Pro pairs the most refined mapping on our list with anti-tangle brushes; the roborock Qrevo keeps both for less, with twice the owner record. roborock's support figure is 2 cm for both.

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 the door bars first. The TP-Link Tapo RV30 Max Plus has the highest published figure of the seven at 22 mm, LiDAR mapping and an auto-empty dock, and 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 eight weeks between bag changes, per eufy: no tanks to fill, nothing to mop. eufy publishes no climb height for it 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, which is where the makers' figures cluster: 1.6 cm from iRobot, 20 mm from eufy for the X10 Pro Omni, 2 cm from roborock, 22 mm from Tapo. Lifting-chassis machines claim 3.5 to 4 cm and more, but none is among our seven. eufy attaches "under ideal conditions" to its 2 cm figure for the Omni C28, and that applies to all of them: a bevelled edge on a hard floor is the ideal condition.

Can a robot vacuum do stairs?

No. None of the seven on our list climbs a stair; what they carry is anti-drop sensors that stop the robot at an edge. eufy's manual says they keep the X10 Pro Omni from tumbling down stairs in most cases, and that they are less effective when dirty or on carpeted or reflective floors. roborock's manual says not to leave shoes or mats near stairs, because the robot may fall. For a two-storey house that means a second robot, or one carried up that stores more than one map, as our buying guide says.

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 the risk, in both directions. A fringe or 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 leaves a rug damp unless the mops lift clear, which is why eufy's manual keeps the X10 Pro Omni off rugs thicker than 18 mm.