Cleaning grout with a steam cleaner

Cleaned your tiles, but the grout's still grey? Then the dirt isn't on the grout, it's in it. With most grout, a cloth or spray simply can't reach it.

Cleaning grout with a steam cleaner is often the answer. The heat softens the dirt, the pressure pushes it out and a small brush lifts it to the surface. It doesn't work on every type of grout or every problem. Below, you'll find what's in your grout, what steam can do about it and how to tackle it. Looking for a steam cleaner for grout? At the bottom, you'll see which model suits you.

Assess your grout before you start steaming

What you see	What it usually is	What steam does for this grout
Grey, dull grout on floors or in the kitchen	Dirt, grease and soap residue in the pores	Loosens it. This is where steam works best
Black or green spots, especially in the bathroom	Mould or damp staining	Removes it from the surface. If it's deep in the grout or the silicone sealant, the discolouration will remain
White, crusty layer	Limescale	Doesn't dissolve it. It does shift the grease and soap around it
Grout stays dark after drying	Discoloured material	Steam won't help any more. Consider grout paint or regrouting

Tip for a quick test: steam a small, inconspicuous patch and let it dry completely. Is it lighter? Then there was dirt in it. Still just as dark? Then the grout itself is discoloured.

Which grout can you clean with a steam cleaner?

Always check the care instructions from your tile or floor manufacturer. Test on an inconspicuous spot, use the lowest setting that works and keep moving. The table below is a guide:

Type of grout	Steam it?	Why
Cement grout, intact and undamaged	Yes	Porous, so steam reaches the dirt inside. This is the standard grout between tiles
Epoxy grout	Yes, as long as you keep moving	Dense and non-porous, so little dirt soaks in. Epoxy resin can soften with sustained heat, though, so don't stay in one spot
Grout in ceramic or porcelain mosaic	Yes, but allow more time	Lots of grout per square metre. Work in smaller sections
Grout between natural stone, quarry tiles or cement tiles	Only if your supplier allows it	Steam itself doesn't etch the stone, but the tile's finish and protective coating determine what's safe. When you steam, you'll always touch the edge of the tile
Crumbling or damaged cement grout	No	Does sand come away when you rub it, or is a piece missing? Then moisture gets behind the tile. Repair the grout first
Silicone sealant and silicone joints	No	The high steam pressure removes the silicone sealant. These are the flexible edges in corners, along the bath and between the basin and the wall
Joins in laminate or tile-effect PVC	No	These aren't grout lines but joins. Moisture seeps in and the floor can swell

Where steam isn't the answer

A steam cleaner does a lot, but not everything. In these three situations, it won't help much.

Stubborn limescale. This is the main limitation. Limescale is calcium carbonate, and heat and water alone won't dissolve it. Steam does loosen the grease and soap residue around the limescale, so a lot of it often disappears. But a thick, dried-on layer of limescale will stay put and needs a product made for the job. Check carefully that the product is suitable for your tiles and grout.

Silicone sealant. Steam loosens the sealant, so clean silicone sealant with a soft cloth instead. If there's mould in the sealant, cleaning won't help: the mould has grown into the material and replacing the sealant is the only solution.

Permanently discoloured grout. If grout has been damaged by mould or an acidic product, the colour of the material itself has changed. At that point, steam won't fix it. Your options are grout paint or having the tiles regrouted. 

Three things not to do

• No acids on cement grout or natural stone. Vinegar and citric acid work on limescale, but cement grout contains lime itself. The acid dissolves it, leaving grout that's more porous than before and holds on to dirt faster. Marble, travertine and limestone are largely made of lime too: acid leaves dull, etched patches that you can't polish out. Steam doesn't have this problem, because you're only using water.
• Never put cleaning products in the water tank. They can damage the pipes and boiler of your steam cleaner. A steam cleaner runs on water, and nothing else.
• Never steam over a cleaning product. If you've used a product somewhere, rinse it off thoroughly with cold or lukewarm water first and let it dry before you pick up the steam cleaner. Bleach in particular must never be heated: it releases chlorine fumes that harm your airways, even with a window open.

How to clean grout with a steam cleaner, step by step

1. Check your grout. Is it intact, and can this material handle steam? See the table above. Keep away from silicone sealant.

2. Fill the water tank and let it heat up. Use clean tap water, or demineralised water if you live in a hard water area. The heat-up time depends on your model: the TS Compact is ready in about 10 seconds, the TS3 Edge in about a minute. With the TS1 and TS2, allow two to eight minutes.

3. Steam off the condensation, pointing away from you. Do this into the sink until only steam comes out. If you skip this step, you'll spray water onto your grout instead of steam. The dirt gets wet, but it won't come loose.

4. Click a small nylon brush onto the precision nozzle. Without a brush, you're only blowing. Our models come with a brush set, so you can get started right away. Always start with nylon, as brass and steel brushes are meant for heavy-duty jobs on tough surfaces such as the barbecue.

5. Work in sections of half a metre. Do a section of grout, wipe it, then move on. On wall tiles, work from top to bottom so loosened dirt doesn't run over areas you've already cleaned.

6. Keep moving and don't stay in one spot. Scrub gently back and forth a few times on each section, and don't press harder than you need to. This matters for two reasons. With cement grout, steaming the same spot for too long pushes hot water deeper into the porous grout, and if the room doesn't dry properly afterwards, that can actually encourage mould. With epoxy grout, the resin can soften under sustained heat. Short and even works better than long and intensive.

7. Wipe away the loosened dirt straight away. This is the step people skip most often. A steam cleaner doesn't pick anything up. The dirt sits loose on the surface, and if you leave it, it sinks back into the grout as it dries. Go over it straight away with a microfibre cloth, and refold or rinse the cloth regularly.

8. Mop the floor and let the room dry. Once you've done the grout, loosened dirt will be left on your tiles. Finish off with the floor attachment and a clean cloth. Then open a window or switch on the extractor fan, so any moisture that has soaked into the grout can dry out.

For an average bathroom floor plus the wall around the shower, allow 45 minutes to an hour the first time you give the grout a thorough clean. After that, it's much quicker.

Want to steam the tiles themselves too? Read how to clean tiles with a steam cleaner.

Only judge the result once the grout is dry

Wet grout always looks darker than it really is. Wait half an hour before you judge the result or go over it again. Lots of people steam grout a second time when it was already clean. If you want before-and-after photos, take both when the grout is dry and in the same light.

How to keep your grout clean for longer

• Wipe down wet bathroom walls after showering and keep the room ventilated.
• Wipe away grease in the kitchen before it dries into the grout.
  

Which model suits your grout?

For grout, the wet steam setting works best, and two of our four models have it.

• TS Compact if you're mainly cleaning a bathroom or kitchen. Wet and dry steam, ready in about 10 seconds, and at 1.3 kilos it's light enough to use on walls for longer.
• TS3 Edge if you clean grout often and larger surfaces too. You also get wet and dry steam, a 2.5-litre tank you can refill while you clean, and the highest steam output of all our models.
• TS1 or TS2 Performance if floors are your main job and grout comes second. These have a single steam setting and run for 40 and 50 minutes respectively on a full tank.

You'll find every model, and the attachments that come with each one, in our steam cleaners for grout. Not sure which to choose? Try Help me choose.