Best Foam Cannon for a Pressure Washer UK (2026)

A foam cannon for a pressure washer is the bottle that holds car shampoo on the panel so you can mitt and rinse. People also search it as foam cannon pressure washer, or snow foam lance. On a UK home washer it is an accessory, not a second machine.

This page is the buyer guide for adding one to a tap-fed Kärcher, Bosch or Nilfisk. Specs come from the manufacturers. Street prices come from Amazon, Screwfix, Wickes, B&Q and the brand shops in August 2026.

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Start with the machine you already own, or the one you are about to buy. A K4 or K5 takes a dedicated foam jet (Kärcher FJ 10 C, about £30 to £33). Plug ‘n’ Clean shampoo through the body is fine for a quick wash. It is not a snow-foam layer. The Bosch UniversalAquatak 135 already puts a 450 ml bottle on the lance. The Nilfisk Core 140-8 Car Wash kit puts a Super Foam sprayer in the box.

Paint-safe settings and the wash order sit on the cars page. The brand-agnostic mains shortlist is the electric pressure washer guide. The yellow range in full is the Kärcher hub. Bosch and Nilfisk have their own hubs (Bosch, Nilfisk). First-use setup and frost drain-down are on how to use a pressure washer.

What to buy

There is no standalone foam-cannon listing on this site with a live shop path. Buy the washer that already soaps a car, or buy the K4 and add an FJ 10 C from Kärcher later. Do not pay extra for a Car & Home carton just to get a foam bottle you can clip on afterwards.

Comparison table

Path	How it soaps	Max pressure	Flow	Hose	Foam in the box?	Typical UK price (Aug 2026)
Kärcher K4 Power Control Flex	Add an FJ 10 C foam jet later. Plug ‘n’ Clean in the body is a thin shampoo, not a snow-foam layer	20 to 130 bar	420 L/h	8 m PremiumFlex	No, on the bare Flex	£200 to £220. FJ 10 C about £30 to £33 extra
Nilfisk Core 140-8 Car Wash	Super Foam sprayer in the kit	140 bar	465 L/h max (348 L/h rated)	8 m UltraFlex, internal reel	Yes	£240 kit. Standard 140-8 is £186 without Super Foam
Bosch UniversalAquatak 135	450 ml high-pressure bottle on the lance	135 bar	410 to 450 L/h	7 m PVC	Yes	£128 Wickes. Bosch lists £184

Prices checked August 2026. Home and Car & Home Kärcher kits cost more and sometimes include a foam or wash bottle. Confirm what is in the carton. The FJ 10 C figure is the range already used on the cars and Kärcher pages. There is no shop shortlink for that accessory on this site.

What a foam cannon is

A foam cannon, a snow foam lance and a foam jet are the same job with different badges. Water from the washer mixes with car shampoo in a bottle and throws a thick film onto the paint. That film holds grit so a mitt can lift it, instead of dragging it down the panel.

It is not a dirt blaster. It is not patio cleaner. It is not a reason to buy 180 bar. The useful part is dwell time on the lacquer, then a wide-fan rinse.

Four ways UK home washers soap a car

• Dedicated foam jet (Kärcher FJ 10 C). Clips onto a K-series gun in place of the Vario. About £30 to £33. This is the snow-foam layer the cars page means when it says a foam jet is worth more than another 15 bar.
• Plug ‘n’ Clean in the Kärcher body. A bottle sits in the machine and feeds shampoo through the lance on the detergent setting. Fine for a weekly hatchback. It is not a thick foam blanket.
• Bottle on the lance (Bosch 450 ml). Soap lives at the gun, not in the trolley. You see how much is left. You do not need a second accessory.
• Nilfisk Super Foam sprayer. In the Core 140-8 Car Wash kit, not in the £186 standard box. Same idea as a foam jet: hold soap on the panel, then rinse on the gentle nozzle.

A cheap generic cannon that fits the lance is fine if the bottle is car shampoo. Patio detergent is not. Washing-up liquid strips wax and dries seals. Match the soap to the surface. That rule is on the how-to page as well.

Which washers have the flow

Foam needs water volume more than peak bar. 360 L/h on a K2 feels thin on a dirty estate. 420 to 500 L/h is the comfortable mains range. That is why the cars guide is written around a K4, not a K2, and why a K5 is a driveway upgrade rather than a better foam machine.

• 110 bar, 360 L/h (K2). Enough for a careful foam-and-rinse on one small car. Slow. Short hose. Fine if you already own it. Not the washer to buy for foam.
• 130 to 140 bar, about 410 to 420 L/h (K4, Bosch). The useful home class. Enough flow to rinse foam, enough control to stay off the paint.
• 140 bar, 465 L/h peak / 348 L/h rated (Nilfisk Core 140-8). Peak flow will rinse foam. The rated figure is closer to a K2. Buy this machine for the reel and the Super Foam kit, not because the box says 140 bar.
• 145 bar, 500 L/h (K5). Faster rinse and a 10 m hose. Cars do not need the extra bar. If the drive is long, that argument is K4 vs K5.

A garden hose is about 2 to 4 bar. A cordless gun at 20 to 56 bar will do a careful foam-and-rinse if you bring a second battery. It will not match a tap-fed K4 for a weekly family wash. Petrol 200 bar-plus frames are the wrong tool for gloss paint.

Kärcher K4 Power Control Flex

The washer to buy if you want a Kärcher and a foam jet later

• Buy: Amazon around £200 (RRP £240) · Screwfix £199.97 · B&Q £209 · Kärcher UK £219.99
• Pressure / flow: 20 to 130 bar, 420 L/h
• Hose: 8 m PremiumFlex
• Motor: 1.8 kW, water-cooled
• Weight: 11.5 to 12.1 kg without accessories
• In the box (bare Flex): G 160 Q Power Control gun, Vario Power lance, dirt blaster
• Foam: none on the bare Flex. Add an FJ 10 C, about £30 to £33. Plug ‘n’ Clean sits in the body if you want a thin shampoo through the lance
• Who it is for: anyone who wants one car washer that will also do furniture and a small patio, then a proper foam jet when they are ready

130 bar with a twist-to-adjust Vario is the useful UK sweet spot for paint. You drop the setting for bodywork and glass, then open it for arches and wheels. The LED on the G 160 Q gun shows the step, so you are not guessing. That control is why a foam jet on a K4 beats a thicker foam on a machine you cannot turn down.

The Flex hose is the reason to buy this SKU rather than an older stiff-hose K4. Eight metres walks a family car if you park the trolley at a corner. The dirt blaster in the box is for stone, not lacquer. Leave it on the hook when the car is out.

Home kits add a T 5 and stone cleaner. Buy that box if you will use the head. Car & Home adds foam, a brush or shampoo on top. B&Q has listed Car & Home at £259. Amazon Car & Home has been around £298. Useful if those extras are cheap in the bundle. Easy to overpay when the banner just says Home. Do not pay extra for a foam bottle you can add later as an FJ 10 C.

If the drive is long and filthy, the K5 Flex has 500 L/h and 10 m of hose. That is a driveway upgrade, not a better foam cannon. Keep the K4 and spend the difference on the jet, a mitt and shampoo. The class argument is K4 vs K5. The rest of the yellow range is on the Kärcher hub.

Skip it if you already own a Bosch or a Nilfisk and you only wanted a bottle. Stay in that clip system. Skip it if you only rinse one small car and will never touch the patio. A K2 will do that for less, slowly. Skip it if there is no outdoor socket or no tap. A foam jet will not invent a 13A point.

Nilfisk Core 140-8 Car Wash

The kit to buy if foam and winter arches are the point, and you do not already own yellow bottles

• Buy: Nilfisk shop £186 standard, £240 Car Wash kit · Nilfisk UK
• Pressure: 140 bar max, three power steps (100 / 80 / 60%)
• Flow: 465 L/h max, 348 L/h rated
• Hose: 8 m UltraFlex on an internal reel
• Motor: 1.8 kW
• Weight: 8.7 kg
• In the box (standard): detergent sprayer, gentle nozzle, rough nozzle
• Car Wash kit adds: Super Foam sprayer and an underbody / arch lance
• Who it is for: buyers who want a metal pump, a hose reel and foam in the carton, especially on a UK winter car

The Super Foam sprayer is the reason this kit exists on a foam page. It is not more bar and it is not more hose. The standard 140-8 at £186 already includes a detergent sprayer. That is enough if you already own a foam bottle, or if the patio is half the job. Pay the extra £54 when foam and arches are why you are shopping.

Use the gentle nozzle on paint. Leave the rough nozzle for stone. PowerControl lets you knock the pump back a step without changing the tip. That is the same idea as Kärcher’s Vario, done with a knob and two Click and Clean jets. The Super Foam sprayer is the soap, not a reason to skip a mitt.

Read the flow line. 465 L/h is the peak. The rated 348 L/h is closer to a K2 than a K4 at 420 L/h. Foam will rinse. A long, filthy drive will feel slower than a K5. Buy this machine for the reel, the aluminium pump head and the kit, not because the box says 140 bar.

Do not confuse the current 140-8 (8 m, reel) with older 140-6 stock (6 m, no reel). Same pump class, worse reach. Warranty is two years, with an option to extend to five if you register it. The ten-year promo closed in June 2026.

How this machine sits against a K4 and a Bosch is on the Nilfisk hub and the electric guide. Car-wash order sits on the cars page.

Skip it if you already own Kärcher detergents and lances. Stay yellow. Skip it if you want the cheapest named 130 bar class with soap already on the lance. That is the Bosch at Wickes. Skip it if you want an 8 m Flex hose you pull off a hook and a gun that shows the pressure step. That is the K4.

Bosch UniversalAquatak 135

The washer to buy if you want soap on the lance and you will carry the machine

• Buy: Wickes £128 · Bosch DIY lists £184
• Pressure: 135 bar max
• Flow: 7.5 L/min max (Bosch). Wickes quotes 410 L/h
• Hose: 7 m PVC
• Motor: 1.9 kW
• Weight: 7.9 kg without accessories
• In the box: gun, lance, 3-in-1 nozzle (fan, rotary, pencil), 450 ml high-pressure detergent bottle, water filter
• Who it is for: flats with a parking bay, smaller cars, and anyone who will carry the washer up steps rather than wheel a Kärcher trolley

Bosch puts the detergent in a 450 ml bottle on the lance. That is the honest way to soap a car if you do not want a separate foam cannon. Fan jet for paint. Rotary for stone. Pencil for the bits of the drive that are not a car. That trio is clearer than a dirt blaster people leave clicked on by mistake.

The 450 ml bottle is enough shampoo for a hatchback if you foam first and rinse with purpose. It will not throw the thick blanket a dedicated FJ 10 C throws on a K4. It will hold soap on the panel, which is the job. You do not then need a second clip-on bottle.

It is lighter than a K4 by a useful margin. The hose is a metre shorter and it is ordinary PVC, not Kärcher’s Flex. You will move the trolley more often around a large estate car. Push-fit connections and a quieter pump are the comfort extras. The metal three-cylinder pump is a better spec than the Wickes ticket suggests.

Wickes is the live UK price to start with. Bosch’s own £184 is the list, not the street. The Bosch in full is the Bosch hub. How it sits next to a K4 is on the electric guide.

Skip it if you already own Kärcher lances and bottles and want to stay in that system. Skip it if you want an 8 to 10 m hose and a gun that shows the pressure step. That is the K4 or K5. Skip it if you wanted Super Foam and an arch lance in the carton. That is the Nilfisk kit.

How to use a foam cannon

Soap is a low-pressure job. Fit the foam jet, the Bosch bottle or the Super Foam sprayer, apply, wait, then rinse on a wide fan. High-pressure soap just wastes shampoo and sends foam into the drain. The full car order is on the cars guide. The short version is below.

1. Pre-rinse on a wide fan, a sensible distance, to float off loose grit. Work from the bottom up so you can see what is left.
2. Apply car shampoo or snow foam. Do not build a pile that slides off under its own weight. Do not let it dry. Work a panel or a side at a time.
3. Agitate with a clean mitt if the film is heavy. Two buckets if you are using a mitt: one wash, one rinse. The foam cannon does not replace that on a neglected car.
4. Swap back to the Vario, the fan jet or the gentle nozzle. Rinse on the same wide fan, still at a distance. Roof, glass, then sides, then sills.
5. Rinse the bottle and the lance after, or the next rinse still spits soap.

Kärcher’s own car-wash advice is a flat jet, at least 15 cm from the paint and 30 cm from the tyres. Further back is safer on old lacquer, vinyl wraps, chrome, rubber seals and anything with a camera or sensor in it. Do not use the dirt blaster, rotary nozzle or a pencil jet on paint.

Check you are allowed to wash on that drive. Some councils treat runoff on the public highway as a problem even with no soap. On private land, soapy water should go to a drain, not into a soakaway or a river. If the only path is a road gully, skip the detergent or take the car to a wash that already treats the water.

Skip it if

• The only job is slabs. A foam cannon is a car accessory. Stone wants a patio head and stone cleaner, not snow foam. Start with the patio or driveway guide, not this page.
• You already have soap that stays on the panel. A Bosch bottle, a Nilfisk Super Foam sprayer or an FJ 10 C you already own is the job done. Do not buy a second bottle for the same gun.
• There is no outdoor tap, or no 13A socket. A foam jet will not invent either. Start with the cordless guide, or a tank trolley if the missing thing is water.
• You were about to buy a K5 or a K7 for thicker foam. Extra bar does not make better foam. Keep the K4. The K5 is a 10 m hose and 500 L/h for a long drive. The K7 is a large-plot machine.
• You want a detailing wall box with a cannon in the kit. That is a different page and a different budget. A home K4 plus an FJ 10 C is the usual UK answer.

What we left out

A standalone FJ 10 C buy block. The cars, Kärcher and comparison pages already quote about £30 to £33. There is no verified shop shortlink for that accessory on this site, so it is not a card here. Buy it from Kärcher or a Kärcher centre when you already own the gun it clips onto.

Generic no-name foam cannons. A bottle that fits the lance is fine if the soap is car shampoo. Mystery pumps, odd threads and patio detergent sold as “snow foam” are how people mark paint. Stick to the clip your washer already uses.

K2 as a foam machine. 110 bar and 360 L/h will wash a car if you foam first and stay on the wide Vario. The 5 m hose is the daily frustration. Treat a K2 you already own as good enough. Do not buy one because this page mentioned foam.

Cordless and petrol. A battery gun will do a careful foam-and-rinse on one car if you bring a second pack. A petrol frame will throw foam and then cut lacquer if you get close. Neither is the home foam-cannon path.

FAQ

What is the best foam cannon for a pressure washer in the UK?

On a Kärcher, a dedicated FJ 10 C foam jet, about £30 to £33, on a K4 Power Control Flex. That pair is the usual UK home answer: 420 L/h to rinse, a gun that shows the pressure step, and soap that actually sits on the panel. If you do not own a washer yet and foam is the point, the Nilfisk Core 140-8 Car Wash kit at £240 puts Super Foam in the carton. If you want soap without a second accessory, the Bosch UniversalAquatak 135 already has a 450 ml bottle on the lance.

Do I need a foam cannon?

You need soap that stays on the panel. A Kärcher FJ 10 C, the Nilfisk Super Foam sprayer or Bosch’s 450 ml bottle all do that. Plug ‘n’ Clean through a Kärcher body is a thinner shampoo, still better than a dry blast. Patio detergent is not a foam cannon fill.

Will a foam cannon work on a Kärcher K2?

Yes, if the jet fits the gun and you stay on the wide Vario. 110 bar and 360 L/h will apply foam. The rinse is slow and the hose is short. A K4 is the machine to buy if you are shopping for foam and you do not already own a washer.

K4 or K5 for foam?

K4. Foam does not need 145 bar. The K5 earns its keep with 500 L/h and 10 m of hose on a long or filthy drive, not with a thicker blanket. That split in full is K4 vs K5.

Can I put patio cleaner in a foam cannon?

No, not on a car. Patio detergent is for stone. On paint it dulls lacquer. Use car shampoo or snow foam on a bonnet. Use stone cleaner on slabs, through the detergent setting or a patio head, not as a snow-foam layer on a wing.

How do I use a foam cannon on a car?

Pre-rinse on a wide fan, foam, mitt if the film is heavy, then rinse on the same wide fan. Stay at least 15 cm from paint and 30 cm from tyres. Further is safer. Do not let the foam dry. Do not chase a tar spot with the dirt blaster. The full order is on the cars page.

Does a Bosch need a separate foam cannon?

No. The UniversalAquatak 135 already has a 450 ml bottle on the lance. That is enough for a hatchback if you foam first and rinse with purpose. Buy a separate cannon only if you want a thicker layer and you have checked the clip fits. The Bosch hub is here.