1
00:00:00,000 --> 00:00:04,480
Ask ten exterior cleaners what a one to
five mix is, and I'd bet you get at least
2
00:00:04,540 --> 00:00:07,920
two different answers about what's
actually going onto the wall.
3
00:00:08,080 --> 00:00:09,520
That's a problem.
4
00:00:09,620 --> 00:00:14,320
Because when the slang is fuzzy, the
chemistry is fuzzy, and when the chemistry is
5
00:00:14,387 --> 00:00:19,920
fuzzy, somebody's render, somebody's
margin, or both, are being gambled with.
6
00:00:19,958 --> 00:00:24,838
I'm Mark Cave from SoftWash UK, and today
is a straight talking one about a mistake
7
00:00:24,958 --> 00:00:26,598
I see constantly.
8
00:00:26,665 --> 00:00:31,478
Contractors confuse part ratios with the
actual percentage of active chemical
9
00:00:31,542 --> 00:00:32,998
they're applying.
10
00:00:33,000 --> 00:00:34,120
Let's start with the stock.
11
00:00:34,360 --> 00:00:40,280
In the UK, commercial sodium hypochlorite
typically arrives at 14 to 15 percent
12
00:00:40,344 --> 00:00:41,720
available chlorine.
13
00:00:41,987 --> 00:00:47,480
We supply it in 20 litre boxes, four 5
litre containers to a box.
14
00:00:47,667 --> 00:00:51,160
So let's use 15 percent as our working
figure.
15
00:00:51,167 --> 00:00:53,807
Now, somebody says, I run a one to five.
16
00:00:53,823 --> 00:00:54,527
What does that mean?
17
00:00:54,647 --> 00:00:58,447
One part sodium hypochlorite, five parts
water.
18
00:00:58,527 --> 00:00:59,327
Count them up.
19
00:00:59,391 --> 00:01:01,007
That's six parts in total.
20
00:01:01,087 --> 00:01:01,807
Not five.
21
00:01:02,007 --> 00:01:02,687
Six.
22
00:01:02,807 --> 00:01:08,047
And the strength you're applying is the
stock strength divided by the total parts.
23
00:01:08,207 --> 00:01:12,927
So 15 percent divided by 6 gives you 2.5
percent.
24
00:01:12,958 --> 00:01:14,518
Here's where it goes wrong.
25
00:01:14,738 --> 00:01:18,558
A lot of contractors divide by the water
parts alone.
26
00:01:18,638 --> 00:01:23,758
They take 15, divide by 5, and tell
themselves they're putting on 3 percent.
27
00:01:23,838 --> 00:01:24,878
They're not.
28
00:01:24,926 --> 00:01:26,560
They're putting on 2.5.
29
00:01:26,688 --> 00:01:31,760
That's a gap of half a percent, and it
feeds straight into your chemical budgeting,
30
00:01:31,792 --> 00:01:35,760
your job pricing, and your confidence
about what the surface can take.
31
00:01:35,792 --> 00:01:37,152
Same thing with a one to six.
32
00:01:37,200 --> 00:01:38,912
That's seven parts in total.
33
00:01:39,232 --> 00:01:42,992
15 divided by 7 is 2.14 percent.
34
00:01:43,125 --> 00:01:46,432
If you divide by six, you think you're at
2.5.
35
00:01:46,592 --> 00:01:51,312
So you've got the same slang, a different
answer, and nobody on the van noticing.
36
00:01:51,433 --> 00:01:55,553
And this connects back to our earlier
episode, Softwashing Chemistry: Why Contact
37
00:01:55,673 --> 00:01:56,733
Beats Concentration.
38
00:01:57,533 --> 00:01:59,893
We said dwell time and contact are king.
39
00:02:00,333 --> 00:02:00,573
True.
40
00:02:01,193 --> 00:02:05,453
But you can't control contact until you
know exactly what percentage is sitting on
41
00:02:05,493 --> 00:02:06,113
the substrate.
42
00:02:06,853 --> 00:02:09,473
Contact with an unknown strength isn't
control.
43
00:02:09,893 --> 00:02:10,453
It's hope.
44
00:02:10,542 --> 00:02:12,862
So let's do it properly, with real
batches.
45
00:02:13,002 --> 00:02:16,142
Say you want 100 litres of 2.14 percent.
46
00:02:16,190 --> 00:02:18,382
That's a one to six, seven parts.
47
00:02:18,702 --> 00:02:23,822
100 divided by 7 is about 14.3 litres of
sodium hypochlorite.
48
00:02:24,002 --> 00:02:27,262
Top it up with about 85.7 litres of water.
49
00:02:27,369 --> 00:02:30,782
Roughly 14 and 86 on the measuring marks.
50
00:02:30,792 --> 00:02:33,752
Now 125 litres at 2.5 percent.
51
00:02:33,832 --> 00:02:36,792
That's a one to five, six parts.
52
00:02:37,192 --> 00:02:42,792
125 divided by 6 is about 20.8 litres of
sodium hypochlorite.
53
00:02:42,936 --> 00:02:47,832
Many people round that to 20 litres of SH
and 105 of water,
54
00:02:47,859 --> 00:02:50,872
which lands you just a touch under 2.5.
55
00:02:51,000 --> 00:02:54,952
That's fine, as long as you know you've
rounded and you're not pretending it's
56
00:02:55,032 --> 00:02:55,832
exact.
57
00:02:55,972 --> 00:03:00,712
The habit that matters is working from
total parts, then writing the number down.
58
00:03:00,750 --> 00:03:02,030
Then there's the surfactant.
59
00:03:02,126 --> 00:03:06,590
This is where a lot of people try to fix a
wetting problem with extra strength.
60
00:03:06,690 --> 00:03:07,590
Don't.
61
00:03:07,680 --> 00:03:11,630
Our Clever Wash Softwash Surfactant goes
in at 200 to 1.
62
00:03:11,758 --> 00:03:18,030
That's 500 millilitres per 100 litres of
mix, or 625 millilitres for a
63
00:03:18,110 --> 00:03:19,870
125 litre batch.
64
00:03:19,982 --> 00:03:24,830
What it does is reduce the surface tension
of the water, so the solution clings
65
00:03:24,887 --> 00:03:27,550
rather than sheeting straight off vertical
render.
66
00:03:27,641 --> 00:03:32,590
Better cling means better dwell time, and
better dwell time means a lower strength
67
00:03:32,650 --> 00:03:36,590
can do the oxidising work without brute
force concentration.
68
00:03:36,625 --> 00:03:38,705
So what strengths are we actually aiming
for?
69
00:03:38,985 --> 00:03:42,385
I'll give you the starting points I'd work
from, and I'll be clear,
70
00:03:42,425 --> 00:03:44,385
these are guidance, not gospel.
71
00:03:44,492 --> 00:03:47,025
Every surface gets a test patch first.
72
00:03:47,042 --> 00:03:51,442
Modern thin coat and monocouche renders, K
Rend type finishes,
73
00:03:51,482 --> 00:03:53,602
generally sit at around 1 to 2 percent.
74
00:03:53,802 --> 00:03:56,082
I'd rarely go beyond 2.5.
75
00:03:56,226 --> 00:04:01,522
Push harder and you risk bleaching
pigment, drawing salts, and shocking the surface.
76
00:04:01,735 --> 00:04:08,722
Heavy organic flatwork, concrete and black
spot, typically 2.5 to 3.5 percent,
77
00:04:08,822 --> 00:04:12,882
and only occasionally up to 3.75 for
stubborn lichen.
78
00:04:13,142 --> 00:04:19,042
Degraded timber, keep it strictly under
1.5 percent, and pre wet it,
79
00:04:19,095 --> 00:04:22,482
or you'll be looking at raised grain and a
very unhappy customer.
80
00:04:22,500 --> 00:04:23,940
Why does it work at those levels?
81
00:04:24,077 --> 00:04:27,860
Sodium hypochlorite oxidises organic
contamination.
82
00:04:28,047 --> 00:04:30,740
Algae, mould, moss, lichen.
83
00:04:30,847 --> 00:04:34,260
It breaks that biological growth down at a
cellular level.
84
00:04:34,473 --> 00:04:36,660
It isn't just bleaching the colour out.
85
00:04:36,860 --> 00:04:41,300
But it needs contact time to do it, which
brings us full circle to getting the
86
00:04:41,351 --> 00:04:43,620
percentage right and the cling right.
87
00:04:43,625 --> 00:04:45,705
Now the safety side, because it matters.
88
00:04:45,812 --> 00:04:48,665
Never mix acids with sodium hypochlorite.
89
00:04:48,705 --> 00:04:50,425
You get toxic chlorine gas.
90
00:04:50,569 --> 00:04:53,705
Keep your products segregated, in the van
and in the yard.
91
00:04:53,785 --> 00:04:58,425
When you mix, add the chemical to the
water, never water onto chemical,
92
00:04:58,485 --> 00:05:00,785
because you don't want it splashing at
your face.
93
00:05:00,857 --> 00:05:04,185
Wear your gloves and eye protection, mix
somewhere ventilated,
94
00:05:04,225 --> 00:05:05,465
and stir it through.
95
00:05:05,500 --> 00:05:09,980
On the regulatory side, I'm told under the
Control of Explosives Precursors and
96
00:05:10,060 --> 00:05:16,300
Poisons Regulations 2023, sodium
hypochlorite over 6 percent available chlorine is
97
00:05:16,370 --> 00:05:18,460
treated as a reportable poison.
98
00:05:18,700 --> 00:05:22,620
So expect purchasing validation, and keep
your storage secure.
99
00:05:22,753 --> 00:05:27,260
Check the current guidance for your own
circumstances, because the rules do change.
100
00:05:27,292 --> 00:05:28,972
And one more thing that catches people
out.
101
00:05:29,172 --> 00:05:32,652
Raw sodium hypochlorite breaks down over
time.
102
00:05:32,716 --> 00:05:37,852
Heat, sunlight and age turn it,
ultimately, into salt water and oxygen.
103
00:05:37,985 --> 00:05:42,812
So that drum that's been sitting in a warm
shed since last summer is not the 15
104
00:05:42,852 --> 00:05:44,012
percent you bought.
105
00:05:44,119 --> 00:05:48,412
If you're calculating from 15 on the
label, but the drum is at 11,
106
00:05:48,452 --> 00:05:50,732
every one of your lovely sums is wrong.
107
00:05:50,846 --> 00:05:56,092
Rotate your stock, store it cool and out
of the sun, and test it if you're unsure.
108
00:05:56,125 --> 00:05:58,405
So, what can you do this week?
109
00:05:58,525 --> 00:06:02,125
Stop saying one to five without saying the
percentage.
110
00:06:02,272 --> 00:06:05,245
Write the applied strength on every batch.
111
00:06:05,421 --> 00:06:07,325
Work from total parts.
112
00:06:07,498 --> 00:06:10,845
Check your stock is in date and stored
properly.
113
00:06:11,065 --> 00:06:14,445
And do a test patch before you commit to a
surface.
114
00:06:14,458 --> 00:06:18,618
Podcasts like this are a great place to
learn, but if you're serious about offering
115
00:06:18,682 --> 00:06:23,658
softwashing professionally, the structured
route is the SoftWash UK CPD Certified
116
00:06:23,722 --> 00:06:25,418
Softwash Training Course.
117
00:06:25,445 --> 00:06:29,498
It's online, so you learn at your own
pace, and it goes much deeper into chemical
118
00:06:29,546 --> 00:06:33,018
selection, surface identification, safety
and pricing.
119
00:06:33,151 --> 00:06:37,578
Complete it and you can become an Approved
Softwash Applicator,
120
00:06:37,598 --> 00:06:41,178
get listed in the directory, and join the
National Association of Softwash
121
00:06:41,226 --> 00:06:41,818
community.
122
00:06:41,930 --> 00:06:44,138
Have a look at softwashing.uk.
123
00:06:44,167 --> 00:06:45,847
Knowledge comes before product.
124
00:06:45,927 --> 00:06:46,887
Always has.
125
00:06:46,978 --> 00:06:49,447
Thanks for listening, and I'll catch you
in the next one.
00:00:00,000 --> 00:00:04,480
Ask ten exterior cleaners what a one to
five mix is, and I'd bet you get at least
2
00:00:04,540 --> 00:00:07,920
two different answers about what's
actually going onto the wall.
3
00:00:08,080 --> 00:00:09,520
That's a problem.
4
00:00:09,620 --> 00:00:14,320
Because when the slang is fuzzy, the
chemistry is fuzzy, and when the chemistry is
5
00:00:14,387 --> 00:00:19,920
fuzzy, somebody's render, somebody's
margin, or both, are being gambled with.
6
00:00:19,958 --> 00:00:24,838
I'm Mark Cave from SoftWash UK, and today
is a straight talking one about a mistake
7
00:00:24,958 --> 00:00:26,598
I see constantly.
8
00:00:26,665 --> 00:00:31,478
Contractors confuse part ratios with the
actual percentage of active chemical
9
00:00:31,542 --> 00:00:32,998
they're applying.
10
00:00:33,000 --> 00:00:34,120
Let's start with the stock.
11
00:00:34,360 --> 00:00:40,280
In the UK, commercial sodium hypochlorite
typically arrives at 14 to 15 percent
12
00:00:40,344 --> 00:00:41,720
available chlorine.
13
00:00:41,987 --> 00:00:47,480
We supply it in 20 litre boxes, four 5
litre containers to a box.
14
00:00:47,667 --> 00:00:51,160
So let's use 15 percent as our working
figure.
15
00:00:51,167 --> 00:00:53,807
Now, somebody says, I run a one to five.
16
00:00:53,823 --> 00:00:54,527
What does that mean?
17
00:00:54,647 --> 00:00:58,447
One part sodium hypochlorite, five parts
water.
18
00:00:58,527 --> 00:00:59,327
Count them up.
19
00:00:59,391 --> 00:01:01,007
That's six parts in total.
20
00:01:01,087 --> 00:01:01,807
Not five.
21
00:01:02,007 --> 00:01:02,687
Six.
22
00:01:02,807 --> 00:01:08,047
And the strength you're applying is the
stock strength divided by the total parts.
23
00:01:08,207 --> 00:01:12,927
So 15 percent divided by 6 gives you 2.5
percent.
24
00:01:12,958 --> 00:01:14,518
Here's where it goes wrong.
25
00:01:14,738 --> 00:01:18,558
A lot of contractors divide by the water
parts alone.
26
00:01:18,638 --> 00:01:23,758
They take 15, divide by 5, and tell
themselves they're putting on 3 percent.
27
00:01:23,838 --> 00:01:24,878
They're not.
28
00:01:24,926 --> 00:01:26,560
They're putting on 2.5.
29
00:01:26,688 --> 00:01:31,760
That's a gap of half a percent, and it
feeds straight into your chemical budgeting,
30
00:01:31,792 --> 00:01:35,760
your job pricing, and your confidence
about what the surface can take.
31
00:01:35,792 --> 00:01:37,152
Same thing with a one to six.
32
00:01:37,200 --> 00:01:38,912
That's seven parts in total.
33
00:01:39,232 --> 00:01:42,992
15 divided by 7 is 2.14 percent.
34
00:01:43,125 --> 00:01:46,432
If you divide by six, you think you're at
2.5.
35
00:01:46,592 --> 00:01:51,312
So you've got the same slang, a different
answer, and nobody on the van noticing.
36
00:01:51,433 --> 00:01:55,553
And this connects back to our earlier
episode, Softwashing Chemistry: Why Contact
37
00:01:55,673 --> 00:01:56,733
Beats Concentration.
38
00:01:57,533 --> 00:01:59,893
We said dwell time and contact are king.
39
00:02:00,333 --> 00:02:00,573
True.
40
00:02:01,193 --> 00:02:05,453
But you can't control contact until you
know exactly what percentage is sitting on
41
00:02:05,493 --> 00:02:06,113
the substrate.
42
00:02:06,853 --> 00:02:09,473
Contact with an unknown strength isn't
control.
43
00:02:09,893 --> 00:02:10,453
It's hope.
44
00:02:10,542 --> 00:02:12,862
So let's do it properly, with real
batches.
45
00:02:13,002 --> 00:02:16,142
Say you want 100 litres of 2.14 percent.
46
00:02:16,190 --> 00:02:18,382
That's a one to six, seven parts.
47
00:02:18,702 --> 00:02:23,822
100 divided by 7 is about 14.3 litres of
sodium hypochlorite.
48
00:02:24,002 --> 00:02:27,262
Top it up with about 85.7 litres of water.
49
00:02:27,369 --> 00:02:30,782
Roughly 14 and 86 on the measuring marks.
50
00:02:30,792 --> 00:02:33,752
Now 125 litres at 2.5 percent.
51
00:02:33,832 --> 00:02:36,792
That's a one to five, six parts.
52
00:02:37,192 --> 00:02:42,792
125 divided by 6 is about 20.8 litres of
sodium hypochlorite.
53
00:02:42,936 --> 00:02:47,832
Many people round that to 20 litres of SH
and 105 of water,
54
00:02:47,859 --> 00:02:50,872
which lands you just a touch under 2.5.
55
00:02:51,000 --> 00:02:54,952
That's fine, as long as you know you've
rounded and you're not pretending it's
56
00:02:55,032 --> 00:02:55,832
exact.
57
00:02:55,972 --> 00:03:00,712
The habit that matters is working from
total parts, then writing the number down.
58
00:03:00,750 --> 00:03:02,030
Then there's the surfactant.
59
00:03:02,126 --> 00:03:06,590
This is where a lot of people try to fix a
wetting problem with extra strength.
60
00:03:06,690 --> 00:03:07,590
Don't.
61
00:03:07,680 --> 00:03:11,630
Our Clever Wash Softwash Surfactant goes
in at 200 to 1.
62
00:03:11,758 --> 00:03:18,030
That's 500 millilitres per 100 litres of
mix, or 625 millilitres for a
63
00:03:18,110 --> 00:03:19,870
125 litre batch.
64
00:03:19,982 --> 00:03:24,830
What it does is reduce the surface tension
of the water, so the solution clings
65
00:03:24,887 --> 00:03:27,550
rather than sheeting straight off vertical
render.
66
00:03:27,641 --> 00:03:32,590
Better cling means better dwell time, and
better dwell time means a lower strength
67
00:03:32,650 --> 00:03:36,590
can do the oxidising work without brute
force concentration.
68
00:03:36,625 --> 00:03:38,705
So what strengths are we actually aiming
for?
69
00:03:38,985 --> 00:03:42,385
I'll give you the starting points I'd work
from, and I'll be clear,
70
00:03:42,425 --> 00:03:44,385
these are guidance, not gospel.
71
00:03:44,492 --> 00:03:47,025
Every surface gets a test patch first.
72
00:03:47,042 --> 00:03:51,442
Modern thin coat and monocouche renders, K
Rend type finishes,
73
00:03:51,482 --> 00:03:53,602
generally sit at around 1 to 2 percent.
74
00:03:53,802 --> 00:03:56,082
I'd rarely go beyond 2.5.
75
00:03:56,226 --> 00:04:01,522
Push harder and you risk bleaching
pigment, drawing salts, and shocking the surface.
76
00:04:01,735 --> 00:04:08,722
Heavy organic flatwork, concrete and black
spot, typically 2.5 to 3.5 percent,
77
00:04:08,822 --> 00:04:12,882
and only occasionally up to 3.75 for
stubborn lichen.
78
00:04:13,142 --> 00:04:19,042
Degraded timber, keep it strictly under
1.5 percent, and pre wet it,
79
00:04:19,095 --> 00:04:22,482
or you'll be looking at raised grain and a
very unhappy customer.
80
00:04:22,500 --> 00:04:23,940
Why does it work at those levels?
81
00:04:24,077 --> 00:04:27,860
Sodium hypochlorite oxidises organic
contamination.
82
00:04:28,047 --> 00:04:30,740
Algae, mould, moss, lichen.
83
00:04:30,847 --> 00:04:34,260
It breaks that biological growth down at a
cellular level.
84
00:04:34,473 --> 00:04:36,660
It isn't just bleaching the colour out.
85
00:04:36,860 --> 00:04:41,300
But it needs contact time to do it, which
brings us full circle to getting the
86
00:04:41,351 --> 00:04:43,620
percentage right and the cling right.
87
00:04:43,625 --> 00:04:45,705
Now the safety side, because it matters.
88
00:04:45,812 --> 00:04:48,665
Never mix acids with sodium hypochlorite.
89
00:04:48,705 --> 00:04:50,425
You get toxic chlorine gas.
90
00:04:50,569 --> 00:04:53,705
Keep your products segregated, in the van
and in the yard.
91
00:04:53,785 --> 00:04:58,425
When you mix, add the chemical to the
water, never water onto chemical,
92
00:04:58,485 --> 00:05:00,785
because you don't want it splashing at
your face.
93
00:05:00,857 --> 00:05:04,185
Wear your gloves and eye protection, mix
somewhere ventilated,
94
00:05:04,225 --> 00:05:05,465
and stir it through.
95
00:05:05,500 --> 00:05:09,980
On the regulatory side, I'm told under the
Control of Explosives Precursors and
96
00:05:10,060 --> 00:05:16,300
Poisons Regulations 2023, sodium
hypochlorite over 6 percent available chlorine is
97
00:05:16,370 --> 00:05:18,460
treated as a reportable poison.
98
00:05:18,700 --> 00:05:22,620
So expect purchasing validation, and keep
your storage secure.
99
00:05:22,753 --> 00:05:27,260
Check the current guidance for your own
circumstances, because the rules do change.
100
00:05:27,292 --> 00:05:28,972
And one more thing that catches people
out.
101
00:05:29,172 --> 00:05:32,652
Raw sodium hypochlorite breaks down over
time.
102
00:05:32,716 --> 00:05:37,852
Heat, sunlight and age turn it,
ultimately, into salt water and oxygen.
103
00:05:37,985 --> 00:05:42,812
So that drum that's been sitting in a warm
shed since last summer is not the 15
104
00:05:42,852 --> 00:05:44,012
percent you bought.
105
00:05:44,119 --> 00:05:48,412
If you're calculating from 15 on the
label, but the drum is at 11,
106
00:05:48,452 --> 00:05:50,732
every one of your lovely sums is wrong.
107
00:05:50,846 --> 00:05:56,092
Rotate your stock, store it cool and out
of the sun, and test it if you're unsure.
108
00:05:56,125 --> 00:05:58,405
So, what can you do this week?
109
00:05:58,525 --> 00:06:02,125
Stop saying one to five without saying the
percentage.
110
00:06:02,272 --> 00:06:05,245
Write the applied strength on every batch.
111
00:06:05,421 --> 00:06:07,325
Work from total parts.
112
00:06:07,498 --> 00:06:10,845
Check your stock is in date and stored
properly.
113
00:06:11,065 --> 00:06:14,445
And do a test patch before you commit to a
surface.
114
00:06:14,458 --> 00:06:18,618
Podcasts like this are a great place to
learn, but if you're serious about offering
115
00:06:18,682 --> 00:06:23,658
softwashing professionally, the structured
route is the SoftWash UK CPD Certified
116
00:06:23,722 --> 00:06:25,418
Softwash Training Course.
117
00:06:25,445 --> 00:06:29,498
It's online, so you learn at your own
pace, and it goes much deeper into chemical
118
00:06:29,546 --> 00:06:33,018
selection, surface identification, safety
and pricing.
119
00:06:33,151 --> 00:06:37,578
Complete it and you can become an Approved
Softwash Applicator,
120
00:06:37,598 --> 00:06:41,178
get listed in the directory, and join the
National Association of Softwash
121
00:06:41,226 --> 00:06:41,818
community.
122
00:06:41,930 --> 00:06:44,138
Have a look at softwashing.uk.
123
00:06:44,167 --> 00:06:45,847
Knowledge comes before product.
124
00:06:45,927 --> 00:06:46,887
Always has.
125
00:06:46,978 --> 00:06:49,447
Thanks for listening, and I'll catch you
in the next one.
