How to remove rust stains from tiled floors, terraces and concrete

What you need

• Nitrile gloves
• Safety glasses
• FFP2 mask
• Medium bristle nylon brush
• Small brush
• Hose or bucket
• Mop or sponge
• Microfibre cloths
• White vinegar for the test
• Coarse salt and lemons
• Bicarbonate of soda
• Rust remover gel with oxalic acid (Leroy Merlin, Bricodepot)
• Neutral pH natural stone cleaner if the floor is marble, terrazzo or limestone
• Rust inhibitor and metal enamel if you need to treat the cause (Xylazel, Montó, Bruguer)

Step by step

1. 1

   Identify the floor with the vinegar test

   Put a few drops of white vinegar in a discreet corner. If it fizzes, the floor contains calcium carbonate (marble, terrazzo, limestone) and you must not use strong acids. If it does not react, it is porcelain, stoneware or concrete and you can carry on.

2. 2

   Find the cause

   Look for the metal object that is releasing rust: plant pot foot, screw, axle, tin. Remove it or protect it so the stain does not reappear after cleaning.

3. 3

   Clean off the dirt and wet the floor

   Sweep, go over with a mop and water with neutral soap, and wet the area with the hose. A wet floor stops the acid soaking into the pores.

4. 4

   Test the product in a corner

   Apply the rust remover to an unobtrusive spot for 5 minutes, rinse and leave to dry. If the shine and colour hold, carry on. If they change, use a gentler method.

5. 5

   Apply lemon and salt or rust remover gel

   For recent stains, cover with salt and squeeze lemon over it. For old stains, apply the gel with a brush to the stain only. Leave for 10-15 minutes with the gel and 30 minutes with lemon. Do not let it dry.

6. 6

   Scrub with a nylon brush

   Scrub in circles, without pressing too hard, with the nylon brush. If the stain gives way, repeat until it has gone. If nothing changes after two applications, do not keep going.

7. 7

   Rinse with plenty of water

   Rinse with the hose or with a mop and several buckets of clean water. It is important to remove all the acid from the grout and the pores. Do not use bleach or any other cleaner until the floor is dry.

8. 8

   Dry and check in side light

   Dry with a cloth and check with a torch or in side light. If a shadow is left, repeat once more. If a matt ring has been left, apply a wax or a water repellent treatment.

9. 9

   Protect the floor

   Once dry, apply a water repellent or anti-stain treatment suitable for the material, following the pack. Put rubber or felt pads under feet and plant pots.

10. 10

    Treat the metal that caused the stain

    Sand the rusty part of the pot or railing, apply rust inhibitor and paint with metal enamel. Leave to dry for 24 hours before putting it back on the floor.

What floor you have and which product suits it

Before buying anything, identify the floor. The same product that makes a rust stain vanish from porcelain can leave a matt circle on terrazzo, because the acid dissolves the calcium based part of the material. Do this test: put a few drops of white vinegar in a hidden corner. If it fizzes, the floor contains calcium carbonate (marble, limestone, terrazzo, some stamped concrete) and will not tolerate acid.

On terraces and patios along the coast, rustic stoneware, non-slip porcelain, polished concrete and reconstituted stone are all common. Indoors you will find ceramic tile, porcelain stoneware and terrazzo. Each needs a different approach.

Methods from gentlest to strongest

Always wet the floor before applying any product. A dry floor soaks up the acid and holds it in the pores, and that is what leaves tide marks. Work with nitrile gloves, glasses, closed shoes and ventilation, and rinse with a hose or a well wrung mop and lots of water.

Level 1, lemon and salt. Cover the stain with coarse salt, squeeze lemon over it and leave for 30 minutes. Scrub with a nylon brush and rinse. It works on recent marks from tin cans, nails or iron plant pots.

Level 2, vinegar and bicarbonate. For marks that have sunk in, spread bicarbonate of soda over the stain, pour on vinegar and let it react for 15 minutes. Scrub and rinse. It is gentle but does not work on old or deep stains.

Level 3, rust remover gel. Gels containing oxalic or phosphoric acid (sold at Leroy Merlin and Bricodepot, and by floor treatment brands such as Fila) are the most effective on porcelain, stoneware and concrete. Apply with a brush to the stain, leave for 10-15 minutes and scrub. Never let it dry.

Level 4, oxalic acid powder. Mix a tablespoon in half a litre of hot water, apply with a brush or sponge, leave for 10-20 minutes and rinse. It is powerful and toxic by contact and if swallowed. Keep it locked away if there are children or pets. Wear an FFP2 mask if dust is raised.

Level 5, professional product or treatment. For very old stains, large areas or delicate floors, professional cleaning with a rotary machine and specific products is the safe way out. Before spending time, check the type of stain: rust that shows as a brown ring with a lump in the middle usually has a piece of metal underneath.

Common mistakes on terraces and tiles

• Using acid on marble, terrazzo or limestone. The floor loses its shine and is left with a permanent white mark. If you are not sure, do the vinegar test in a corner.
• Mixing acids with bleach. Rust remover, lemon or vinegar mixed with bleach releases chlorine gas, which is dangerous on closed terraces and in bathrooms. Rinse the floor well and wait for it to dry before using any other product.
• Applying on a dry floor or in the sun. The product dries in minutes and leaves a ring. Wet the floor and work in the shade, first thing in the morning or last thing in the day.
• Scrubbing with a wire wool pad. Fragments of steel get embedded and cause fresh rust stains a few days later.
• Treating the stain and not the cause. The iron plant pot, the chair foot or the barbecue axle will keep releasing rust every time it rains.
• Forgetting the joints. Rust soaks into the cement grout. Brush with a soft bristled brush and rinse. For stained grout in general, see how to clean tile grout.

When to call a professional

Call us when the stain is large, when it affects a marble or terrazzo floor, when you have already tried two products and it will not shift, or when there is a wide terrace area with rust several years old. It is a maintenance job that falls under the handyman hourly rate: €35-45 for the first hour and €28-35 for each hour after that. For a big terrace we give you a fixed price from a photo before we come.

If the floor is cracked, lifting or has loose tiles, repair comes before cleaning. Replacing a loose tile or regrouting counts as building work at €30-40 an hour, and regrouting a whole bathroom costs €150-300.

You will find more in handyman by the hour, in handyman hourly rates and in small building works. If the rust is in the bath, see how to remove rust stains from a bath.

How to stop the rust coming back on the terrace

On a coastal terrace, salt air speeds up the corrosion of plant pots, parasol bases, table legs and balustrade screws. Every shower of rain carries the rust onto the floor and leaves a reddish ring. Prevention is cheaper than cleaning.

Put rubber or felt pads under the feet of iron chairs, and plastic saucers under plant pots. Paint rusty parts of railings and balustrades with a rust inhibitor and an exterior enamel (Xylazel, Montó and Bruguer all have metal ranges). If the floor is porous stoneware or concrete, a water repellent and anti-stain treatment makes future cleaning easier.

Sweep and rinse the terrace with fresh water from time to time to remove salt and sand. A monthly wash in summer stops rust getting a hold. If you have a second home in Torrevieja or Orihuela Costa, we can check the terrace before your guests or family arrive.