Roomba robot vacuum cleaners are versatile machines that can clean a variety of different floor surfaces.
The ease with which a Roomba can handle different types of flooring depends upon the exact model, of course.
But it is not just different floor surfaces that challenge our Roomba, it is the ease with which they can move from one surface to another in one cleaning session.
Can Roomba go over thresholds or transition strips?
No matter what Roomba model you have, the maximum height threshold the Roomba can cross over during a cleaning cycle is ⅝ inch or 1.6 cm.
And to clarify, by threshold (or transition strip) I mean the length of wood or metal that you see in internal doorways that hide messy joins between wooden floors, tiled floors or carpets.
Basically, if the threshold is more than 1.6 cm high than your Roomba is going to struggle to successfully get over it.
If your transition strip is more than 1.6cm high then you have two alternatives.
- Schedule two separate cleaning cycles either side of the strip so that the Roomba doesn’t need to go over it.
- Use a small piece of carpet, a mat or build a small ramp to lessen the height of “the gap”.
Can Roomba go over rugs?
The difference in height between a carpet and a rug or a wooden floor and rug is much more of a bump than a threshold.
And once again, as long as that difference is less than 1.6 cm, then your Roomba should not have a problem with it.
But, there’s a huge but…
The Roomba can clean most types of floors without problems, but its kryptonite seems to be rugs and thick carpets.
Thick rugs and carpets tend to be “deeper” than 1.6 cm and so it is easy for a Roomba to get stuck because the wheels get stuck in the strands.
And also earlier Roomba models (such as the 400 and 600 series) had bristle rollers and the bristles got caught on the carpet fibres.
Later Roomba models have rubber rollers that are much better at not getting stuck.
But, a Roomba’s problems with rugs does not stop there. I discuss two other rug issues in later sections.
Roombas that have Carpet Boost and Power Boost can do a better job of cleaning rugs and carpets than older models that are designed primarily for hardwood floors and bare surfaces.
For the robot to do a deep clean, it must have powerful suction that could siphon off all the dust and debris hiding under the threads of the rug or carpet.
The Roomba’s ability to perform on rugs is limited and other than the S9, i7, i7+ and the 900 series models, older models may struggle to pull out the dirt and debris from rugs.
This is not to say that Roomba won’t work at all; it’s just not the best choice for thick rugs and carpets.
Another challenge that the Roomba face is crossing over from hardwood floor to high-pile rugs like shag rugs and thick carpets.
In some cases, the robot may stall at the edges because it has difficulty transitioning. In extreme cases, the robot will treat it as an obstacle and avoid it.
Tips for using a Roomba on a rug
- Schedule a separate cleaning time for areas with rugs or thick carpets so the Roomba wouldn’t have a hard time transitioning between floor types or threshold levels.
- Use the Power Mode or the Carpet Mode to deep clean rugs and carpets.
- High-pile area rugs (e.g. shag rugs) with corners that curl up may cause the Roomba to get caught. Manual intervention is necessary to prevent the robot from getting stuck.
- If you own a Roomba that really struggles with rug cleaning, it’s best to just avoid thick rugs and carpets altogether because it may only overwork the motor and the battery.
- A cool hack that may (or may not) work for you is to increase the height of the wheel just a little bit by sticking a regular washer to the wheel. Of course, this is only for users who are used to tinkering with their Roombas and doing all sorts of hacks. It’s not for the faint-hearted or users whose Roombas are still under warranty.
Why do Roombas hate black carpets/ rugs?
Roombas and black carpets/rugs don’t go well together. This includes carpets and rugs with dark patterns. The reason why Roombas don’t work on dark carpets is that it sees black as a vertical edge and avoids it to prevent itself from falling off that edge. In other words, it trips the cliff sensors and thinks it’s about to fall down.
When the Roomba is used on black carpets, it thinks it’s a cliff so the robot would not go past it. It will just bounce back and forth around the dark patterns. The carpet doesn’t have to be solid black to trigger the sensor. This is frustrating because the Roomba can get stuck in one area and will not get any cleaning done.
What is the Roomba black carpet fix?
One would think that iRobot would have a real fix for this problem by now, but, unfortunately, Roomba users have to rely on DIY for a temporary fix. Here are some Roomba hacks to fix the issue:
- The Foil Trick. This method entails covering each of the LED sensors of the Roomba using aluminum foil or HVAC foil tape. Using the foil will reflect back the infrared so it doesn’t sense the dark patterns as obstacles.
This renders the sensor useless when it comes to detecting cliffs, so this should only be used in areas where the Roomba would not be approaching steps, ledges, or stairs. An alternative to the foil are white paper strips and tape.
Over time, dirt and gunk could get in and the foil or paper will come off eventually. So, you may have to redo this several times as necessary.
- Cliff Sensor Fix. This method entails disassembling the Roomba to get to the sensors and actually repositioning the transmitter and the receiver so that they are pointing directly at each other. You need to modify all the sensors for the fix to work. This requires familiarity with the innards of the robot to ensure that you can put things back together.
If you’re ready to take your robot apart, watch this step-by-step tutorial:
The robot will still slow down because the transmitters and receivers around the perimeter in the front are still intact. This means it will still slow down and not ram into things.
It goes without saying that with this method, the Roomba will no longer sense cliffs and edges, so be careful when using it to clean top floors because it will certainly take a dive when it approaches the stairs. Fortunately, the Roomba will still detect virtual wall barriers, so if you have those, there’s really no real danger of your robot falling down the stairs.
- Change the rug or carpet. If you’re not comfortable with the two methods discussed above, you can just replace your dark rug/carpet with something light and preferably no dark patterns that could trip the cliff sensors.
Can Roombas climb the stairs?
The Roomba has come a long way when it comes to churning out state-of-the-art cleaning features, but after all these years, it still can’t climb up the stairs. The irony of it is that there’s a clamor for something that the robot is designed to avoid in the first place.
The cliff sensor technology has been perfected to keep Roombas from diving down stairs and falling off heights. However, iRobot (or any robovac company for that matter) has yet to create a Roomba that can climb the stairs. Perhaps there’s really no reason to create such a robovac, cost considerations, notwithstanding.
Carpeted staircases would have to wait a little while longer. In the meantime, Roomba owners can build ramps to enable the robot to go up and down the stairs.
Can Roombas vacuum under furniture?
Yes. Roombas are designed to fit under furniture, beds, and kitchen kickboards provided that they clear the floor by at least 3.6 inches or 92mm. Otherwise, the robot will just move on right along.
Generally, Roombas do a fine job of cleaning underneath chairs, tables, and furniture.
However, there are times when the robot can get stuck or get wedged underneath furniture. This happens due to a faulty bumper sensor. It thinks that it’s bumping into obstacles so it tries to back up and does the dreaded “circle dance of death”.
If your furniture has low clearance, you can purchase adjustable furniture risers to accommodate the height and heft of the Roomba you have.
What are the dimensions of different Roomba models?
To know if the Roomba would fit under pieces of furniture, here is a table showing the dimensions of different Roomba models.
| Roomba | Weight | Width | Height |
| 400 Series | 6.4 lbs (2.9 kg) | 13.3 in (338 mm) | 3.5 in (88 mm) |
| 500 Series | 7.9 lbs (3.6 kg) | 13.4 in (340 mm) | 3.6 in (92 mm) |
| 600 Series | 7.9 lbs (3.6 kg) | 13.7 in (347 mm) | 3.6 in (92 mm) |
| 700 Series | 8.4 lbs (3.8 kg) | 13.9 in (353 mm) | 3.6 in (92 mm) |
| 800 Series | 8.4 lbs (3.8 kg) | 13.9 in (353 mm) | 3.6 in (92 mm) |
| 900 Series | 8.7 lbs (4 kg) | 13.8 in (350 mm) | 3.6 in (90.85 mm) |
| e Series | 7.9 lbs (3.6 kg) | 13.7 in (347 mm) | 3.6 in (92 mm) |
| i Series | 7.5 lbs (3.4 kg) | 13.4 in (340 mm) | 3.7 in (94 mm) |
| s Series | 8.15 lbs (3.7 kg) | 12.25 in (311 mm) | 3.5 in (86.36 mm) |
As can be seen from the table, Roomba models from different series have more or less the same dimensions. The differences are almost negligible. In terms of height, the i Series robots are the tallest at 3.7 inches and the s series robots are the shortest at 3.5 inches.
The new s series has a slightly different appearance because of its D-shaped body style. It’s designed that way to do deep cleaning into corners and along edges.
The Roombas are still evolving with new advanced features being introduced. This does not necessarily render older models obsolete because they still work pretty damn well. With newer models, you can choose the Roomba that meets your requirements.