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What Is Sugar Soap and How and Where You Should Use It

Yellow glove wiping green wall
(Image credit: Getty Images)

What is sugar soap? If you don’t know, you’ll need it when getting walls and woodwork ready for your next paint job. It’s rarely the most exciting part of a paint project but preparation is key to getting a good finish and sugar soap is an inexpensive solution that helps play an important part in getting it right.

Over time your walls and woodwork will accumulate dirt, grease and grime and you don’t want to be painting a wall when it's dirty or has grease spots on it. The paint won’t adhere properly and you will be left with a poor finish. Properly applied sugar soap will make sure that this doesn't happen.

Here we give you the lowdown on what sugar soap is and how to use it.  

What is Sugar Soap? And What is it Made Of? 

Sugar soap is a mild detergent that is ideal for cleaning paintwork to improve adhesion before you add any new paint. But the obvious question is, is there any sugar in sugar soap? No, it gets its name from the fact that in its powdered form it looks a bit like sugar — it's white and has small crystals.

It typically contains sodium carbonate or sodium hydroxide. Both are water soluble and help remove dirt and grease from paintwork. You can get sugar soap in dried or concentrated liquid form with the dried form being slightly cheaper. This makes it ideal if you are cleaning down very large areas.

The liquid concentrate is the more popular choice as it's really simple to use. You simply add the concentrate to a bucket of warm water and it's ready to go. 

A typical example would be around 150ml of sugar soap to 5 litres of water. But you can add a little more to get a stronger solution for stubborn dirt and grease. (Bear in mind, if you have sensitive skin wear rubber gloves.)

How Do I Use Sugar Soap? 

Once you have made up your sugar soap solution you will need a small sponge — a sponge kitchen scourer is a good choice. You can use the sponge for general cleaning and the scourer if you hit a stubborn spot. Alternatively, use a clean absorbent cloth — not paper towels.

Dip the sponge or cloth in the solution, squeeze to remove some of the solution so you have a damp cloth and start wiping from side to side and work your way down. Once you have wiped clean the area with sugar soap, get a clean cloth and rinse the area with clean warm water and leave to dry. 

How Long After Sugar Soap Can I Paint? 

This depends on what surface you are cleaning with sugar soap. If you are cleaning woodwork, before painting skirting boards for instance, you will be able to start much quicker than if you are cleaning painted walls.

Once you have cleaned and rinsed woodwork you can wipe down with a clean dry cloth to speed up how long you need to wait. You should be able to start painting after 30 minutes, or maybe even sooner. Check the woodwork is completely dry before starting.

If washing down painted or wallpapered walls leave for around an hour before you start painting. Again check that the walls are completely dry, if not leave until they are. (Ventilating the room can help here.)

Pink rubber glove with blue cloth wiping down skirting board

After cleaning and rinsing woodwork, wipe down with a dry cloth so you can start painting quicker (Image credit: Getty Images)

Does Sugar Soap Clean Gloss Paint? 

The simple answer to this is yes it does. You can use it to just clean your gloss paint, but after a few times it will start to take off the high sheen of even the best gloss paint. If using it to prep the woodwork for a new coat of paint then it won’t matter.  

Can I Make My Own Sugar Soap? 

Yes you can, and it's cheap and easy. Soda crystals (opens in new tab) (or washing soda in the US) is a quick, simple and cheap way to make your own version of sugar soap. They contain sodium carbonate, are biodegradable and you will typically find them in your local supermarket at a price that is typically cheaper than sugar soap. 

All you need to do is add to warm water — like sugar soap. Add a couple of cups to a few litres of water and stir. Wear rubber gloves to protect your skin. 

Should I Use Sugar Soap Before Wallpapering? 

If you have removed old wallpaper then there may well be old wallpaper paste residue left on the walls. If this is the case use sugar soap to scrub down the walls to get rid of it. Remember to rinse and leave to dry.  

If you have nice newly plastered walls you shouldn’t need to wash them down with sugar soap. However, when painting new plaster you will need to apply a mist coat before you start painting to help seal the plaster.

Steve is an avid DIYer with over 20 years of experience in transforming and renovating homes. He specialises in painting and decorating, but has strong all-round building skills, having previously worked in the industry for 10 years.