CHOICE membership

Outdoor Cleaning Products

Choice has been big on providing comparison testing on everyday household products.

Would it be possible to also look at outdoor cleaning products/chemicals.

Three things stand out.

  1. How well does the product perform?
  2. Is it value for money?
  3. Is it safe, to you, your house and the environment?
  4. How complete and effective or reliable are the instructions for safe use?
    (That’s four now!)

Typically you are trying to do more than just lift off dirt and dust. Algae, mould, moss and lichen are also the enemy.

Some products appear to have similar ingredients, but the price differences are significant, just on brand identification? Roof cleaner concentrate $99 for 5l on line vs $39 for a competitor at Bunnings. See below for links.

The other consideration is that these products are typically used on larger home cleaning jobs, hence they are not $2.00 projects.


It’s also possible to be left with an impression that some of the active ingredients carry risks that are not well communicated. Eg A user instruction to not spray if rain is likely might be good advice.

Would it be better to have also said avoid run off onto lawns, gardens and waterways for xyz days? This assumes the active ingredient can be harmful to aquatic life and invertebrates, which some can be. You don’t usually need to consider these types of risks for cleaning products used inside the home.


The active ingredients for Wet&Go and 30 Seconds are different…they are outlined in the MSDS for both products:


30 Seconds:

The active ingredients for both products contain compounds which are highly detrimental to aquatic biota and applying these chemicals to outdoor surfaces exposed to the weather increases its risk of being washed into local waterways.

The concern is that the average punter possibly won’t understand the ramifications on not using the product wisely and misuse can potentially cause significant offsite environmental impacts (especially when applied and the compounds when active are allowed to wash from the treated area to stormwater and ultimately waterways).

Many of the things that these compounds treat are potentially not an issue if left untreated. This includes things like lichen on ones roof, moss or moulds on external concrete surfaces etc. These are more cosmetic rather than being a long term damage to the structure covered by these ‘things’.

The other impact could be using these products on roofs which also have rainwater tank systems. The consumption of these chemical compounds due to the chemicals being washed into a rainwater tank may not be wise.

I can see the need for such products where say a walking surface has a high cover of mould/algae and become slippery when wet. However, there are possibly cheaper and just as effective treatments for the mould/algae removal such as a high pressure cleaner, using boiling water/heat gun or even old fashion scrubbing and rinsing.


I did the pressure wash on my driveway twice per year for a decade and it continued to get mildewed again because it is shaded and often damp. The Wet & Forget brushed on the concrete worked a treat and had no visible detrimental affect on the surrounding plant life.

For most things there is a trade off. There are usually alternatives to most anything, but alternatives are not always practical for one or another reason. Re a driveway, one (esp a senior) can only do so much ‘scrubbing and rinsing’ or boiling sufficient water for a fairly long drive, and then waiting to see if the mildew comes back, if that makes a point. As for heat, I did not investigate serious models.



Used to get moss on a concrete pathway which got little sunlight, at the house I was living in. Neat white vinegar, left on for at least a few hours, would kill the spores off and a scrub and rinse off was all that was needed (until the next winter).
Unlike bleach, vinegar penetrates porous surfaces like concrete, and it is not a dangerous substance.
The Home Brand cleaning vinegar is not expensive and easily found at most supermarkets.


Thanks for the request @mark_m, will be sure to pass this onto our product testers :+1:


I’m all for the easy way, and use a number of similar products for prepping the timber before repainting. It takes more than just a mould inhibitor in the paint around here.

If you don’t kill the root of the mould spores it just keeps coming back. I do like the thought of using the direct flaming technique noted by @TheBBG previously. It just might not be that great for the house!

It may help looking further down the 30 Seconds product list. As well as the general outdoor cleaner which uses sodium hyper chlorite, there is a specialty Concentrated Roof Cleaner/treatment product.

MSDS found at:

It contains a quaternary ammonium compound, as does the Wet and Forget Roof Treatment!

For more general cleaning products EG 30 Seconds outdoor cleaner, there is a different chemistry as you have noted.

Many of the outdoor cleaners rely on the action of chlorine to do the neutralising of the mould, moss etc. The delivery mechanism is all that varies.

Somebody more knowledgeable might like to explain where all the chlorine in these products ends up, for better or for worse?


I assume you mean the hypochlorate as found in many bleach solutions then the majority of it ends up as salts, such as sodium chloride, sodium carbonate & Chlorine (Cl2) as it reacts with CO2 in the air, potassium chloride, chloramines and related compounds (the smelly stuff in pool water from reactions with nitrogen compounds), chlorine gas (resulting from reaction with acids where the hydrogen atom bounds with the OH chain creating water and releasing the Cl as Cl2).

As the gas is very reactive it usually ends up then bonding with sodium, potassium or similar metals to form salts as an end product. It also forms other compounds such as chloroform, carbon tetrachloride, and organochlorides but usually at “safe for exposure” levels.


Yes please add these outdoor cleaning products to the CHOICE comparison test. I’m quite keen to see results especially on all those 30 second products considering how dominant they are in Bunnings.