A Basic Guide to Concrete Staining
Applying a concrete stain can transform a surface by adding a unique look, creating character and emphasising aesthetics on both new or old concrete floors. The most common use of concrete staining is in stained concrete floors, which are quickly becoming a popular flooring trend.
What is concrete staining?
A concrete stain is a water-based product that becomes a permanent part of a finished concrete floor or concrete surface. There are two types of concrete stain, reactive and non-reactive, both can be used on new or existing concrete. It is important to remember that results will differ depending on the age, composition, texture and type of concrete, as well as how porous the surface is.
Reactive concrete stain
A water-based acidic solution that produces an effect known as acid wash concrete. Reactive concrete stain contains metallic salts that react with the lime in the concrete surface, resulting in a variety of translucent colours. They can be unpredictable, producing different colours and effects depending on the condition and composition of the concrete surface.
Non-reactive concrete stain
Often a form of water-based acrylic paint. Non-reactive stains produce more predictable and uniform effects, but as they are essentially a paint, they are susceptible to cracking and peeling.
All concrete staining can fade over time, so it is recommended that stained surfaces are sealed once dry. The longevity of the finish will also depend on the environmental conditions and intended use of the finished surface.
How to acid stain concrete
Before you start to acid stain concrete, first you need to ensure the surface is clean and flat. If the concrete has been poured in the last ten years, then it was probably mechanically smoothed, which makes it easier to stain. If the concrete is older, you may need to smooth, or possibly level it first, to achieve the best results.
You’ll also need to check if the concrete has already been sealed. You can do this by pouring a small amount of water onto the surface. If the water does not sink in, then it has already been sealed and you’ll need to strip the sealant off before you can start staining.
Each project will vary depending on the surface, solution, and desired results, but the process will usually follow these steps:
Step one
Wash the surface and apply a degreaser with a stiff brush or buffing machine. It is best to carry out this process twice, to ensure the concrete is as clean as possible. Rinse the surface thoroughly and then leave it to dry fully.
Step two
Test the stain on a small area to give you an idea of the finish. Make sure you like the result, as once an acid stain has been applied it can’t be reversed. Adjust the staining solution depending on the effect and coverage you want to achieve.
Retest until you are satisfied, remembering that variations across the surface of the slab may change the effect and colour of the stain.
Step three
Pour the acid staining solution onto the surface. Each solution will have different instructions and developing time, some solutions will need to be neutralised and rinsed before they are allowed to dry.
Step four
Seal the surface with a water-based sealer. Apply the sealer in thin, even layers, first in an up and down direction, then apply the second coat in a side-to-side direction. This will ensure all pores are filled with sealant.
* At all stages, ensure the appropriate safety precautions are followed for the product you are using, and the environment you are working in.
Benefits of staining concrete
Staining concrete has a number of benefits, in terms of improving a finished concrete floor or surface.
Fire resistance
Stained concrete floors can be used in factories and on building sites where flammable flooring materials such as wood and carpet would not be safe.
Durability
Concrete stain makes floors harder to damage than untreated surfaces. It also protects surfaces against the growth of mould and mildew.
Ease of maintenance
Once sealed, acid wash concrete is waterproof, highly resistant to scratching and much easier to clean.
Transformation/aesthetic
Concrete staining can add character and depth to a plain surface, transforming how it looks and creating an interesting feature.
The alternative to concrete staining
When pouring new concrete, it’s possible to include colour in the mix from the outset. This is as an alternative to using a concrete stain on a new surface. Coloured concrete is available in a range of colours, from subtle shades of beige or grey for decorative use, to red and green for specific safety features.
