1
00:00:00,080 --> 00:00:01,660
Here's a scenario I want you to picture.
2
00:00:02,400 --> 00:00:06,020
You've just finished a lovely softwash on
a cream monocouche wall.
3
00:00:06,640 --> 00:00:08,340
It looks fantastic while it's wet.
4
00:00:08,900 --> 00:00:11,660
You pack up, the customer's happy, and you
drive off.
5
00:00:12,460 --> 00:00:13,840
Then the wall dries.
6
00:00:14,520 --> 00:00:17,860
And suddenly there's a square patch, about
the size of a dinner plate,
7
00:00:18,220 --> 00:00:21,380
that's a completely different shade from
everything around it.
8
00:00:22,740 --> 00:00:25,000
That's the day a clean becomes a dispute.
9
00:00:25,042 --> 00:00:29,442
I'm Mark Cave from SoftWash UK, and today
we're talking about monocouche render.
10
00:00:29,538 --> 00:00:32,882
What the risks are, and how a professional
works around them.
11
00:00:32,917 --> 00:00:34,037
First, what is it?
12
00:00:34,217 --> 00:00:36,997
Monocouche is French for single coat.
13
00:00:37,157 --> 00:00:42,117
It's a pre-mixed, cementitious, mineral
based render, and the key thing is that the
14
00:00:42,177 --> 00:00:44,037
pigment runs all the way through it.
15
00:00:44,197 --> 00:00:46,278
It isn't paint sitting on the surface.
16
00:00:46,457 --> 00:00:49,797
You'll know the big names, Weber, Parex, K
Rend.
17
00:00:49,897 --> 00:00:53,877
You'll see it on loads of modern UK
housing developments and commercial buildings.
18
00:00:53,917 --> 00:00:58,877
It usually has a scraped or textured
finish, and it's open and breathable.
19
00:00:58,973 --> 00:01:00,237
That's great for the building.
20
00:01:00,357 --> 00:01:05,357
But that open, capillary texture holds
moisture, airborne spores and pollution.
21
00:01:05,544 --> 00:01:10,157
So on damp or sheltered elevations you get
green algae, red or orange algae,
22
00:01:10,257 --> 00:01:11,917
and black organic growth.
23
00:01:12,029 --> 00:01:14,397
That's why we get called out to it so
often.
24
00:01:14,417 --> 00:01:15,137
Now, the risks.
25
00:01:15,228 --> 00:01:17,137
Number one is pressure.
26
00:01:17,497 --> 00:01:20,897
I still see people reach for a pressure
washer, or a hard tip,
27
00:01:20,927 --> 00:01:22,897
because the wall looks tough.
28
00:01:23,164 --> 00:01:24,177
It isn't.
29
00:01:24,305 --> 00:01:28,977
High pressure can score and etch the
surface, expose the aggregate underneath,
30
00:01:29,017 --> 00:01:31,217
and blow hollow or blown sections off.
31
00:01:31,397 --> 00:01:32,897
And here's the nasty bit.
32
00:01:33,037 --> 00:01:36,417
The wand stripes often only show once the
wall has dried.
33
00:01:36,630 --> 00:01:40,817
So you can walk away thinking you've done
a great job, and find out later you
34
00:01:40,857 --> 00:01:41,537
haven't.
35
00:01:41,542 --> 00:01:43,382
Number two is metal.
36
00:01:43,446 --> 00:01:47,142
This connects back to what we covered in
the episode on why bleach fails on rust
37
00:01:47,188 --> 00:01:49,702
stains, and the earlier render care
episodes.
38
00:01:49,782 --> 00:01:54,422
Biological staining clears with a gentle
oxidiser like sodium hypochlorite.
39
00:01:54,529 --> 00:01:56,502
Metallic runoff doesn't.
40
00:01:56,646 --> 00:02:02,102
Rusting screws, unpainted brackets,
satellite mounts, copper or lead flashings,
41
00:02:02,182 --> 00:02:05,382
overflow pipes, they all leach into the
render.
42
00:02:05,482 --> 00:02:10,822
Because monocouche is porous and cement
and lime based, that staining goes deep.
43
00:02:10,913 --> 00:02:13,733
If you blast it with hypochlorite, it
won't lift an iron stain,
44
00:02:14,113 --> 00:02:16,813
and it can leave an oxidised, shadowy look
around it.
45
00:02:17,693 --> 00:02:21,993
The usual answer is a targeted acid
treatment, something like oxalic acid.
46
00:02:22,573 --> 00:02:23,753
But be really careful.
47
00:02:24,253 --> 00:02:28,693
Strong acids can etch or react with the
cementitious binder and any limestone
48
00:02:28,773 --> 00:02:29,713
aggregate in the mix.
49
00:02:30,353 --> 00:02:34,813
So it's a test patch first, always, and
it's controlled, never a flood of acid
50
00:02:34,853 --> 00:02:35,513
across the wall.
51
00:02:35,750 --> 00:02:39,030
Number three is something customers never
see coming.
52
00:02:39,101 --> 00:02:40,910
Previous repairs.
53
00:02:41,040 --> 00:02:45,270
Monocouche walls often have hairline
cracks that were filled years ago,
54
00:02:45,323 --> 00:02:49,830
or patches done with unpigmented mortar,
mastic, or a different batch of render.
55
00:02:49,990 --> 00:02:53,510
When the wall's dirty, everything looks
evenly dull.
56
00:02:53,630 --> 00:02:58,630
Clean it, and suddenly you've exposed
batch banding and ugly repair patches.
57
00:02:58,730 --> 00:03:01,590
You didn't cause them, but guess who gets
the blame?
58
00:03:01,718 --> 00:03:04,950
That's why you document everything before
you start.
59
00:03:04,958 --> 00:03:07,358
Number four is strength and drying.
60
00:03:07,406 --> 00:03:11,198
Over concentrated hypochlorite, or letting
an alkaline solution dry quickly on a
61
00:03:11,262 --> 00:03:16,398
warm wall, can cause salt crystals,
surface chalking, or accelerated pigment fading.
62
00:03:16,518 --> 00:03:17,758
The rule is simple.
63
00:03:17,865 --> 00:03:19,998
Never let chemical dry on the substrate.
64
00:03:20,126 --> 00:03:22,720
Work in sections, and keep an eye on the
weather.
65
00:03:22,750 --> 00:03:24,350
So what does good practice look like?
66
00:03:24,510 --> 00:03:27,150
Start with a survey and photographs.
67
00:03:27,264 --> 00:03:32,190
Before any water or chemical goes near the
wall, record the hairline cracks,
68
00:03:32,217 --> 00:03:37,630
chipped corners, rust tails under vents
and fixings, and any previous patch repairs.
69
00:03:37,830 --> 00:03:40,110
Tap the wall to check for blown render.
70
00:03:40,243 --> 00:03:42,990
If it sounds hollow, say so, and record
it.
71
00:03:43,000 --> 00:03:44,120
Next, protection.
72
00:03:44,376 --> 00:03:49,480
Mask delicate aluminium trims, galvanised
brackets and lead flashings.
73
00:03:49,680 --> 00:03:54,360
Pre-wet the plants, the lawn and the
borders below so they're not taking the hit.
74
00:03:54,375 --> 00:03:56,135
Then apply the chemistry at low pressure.
75
00:03:56,315 --> 00:04:00,455
For monocouche, a controlled mix is
typically somewhere between one and a half and
76
00:04:00,495 --> 00:04:04,375
two and a half percent applied sodium
hypochlorite, with a bleach stable wetting
77
00:04:04,423 --> 00:04:08,295
surfactant such as Clever Wash, so it
clings to the wall instead of running straight
78
00:04:08,375 --> 00:04:08,775
off.
79
00:04:08,995 --> 00:04:13,175
Use a dedicated low pressure system, like
a twelve volt pump or a calibrated
80
00:04:13,235 --> 00:04:13,815
Dosatron.
81
00:04:13,911 --> 00:04:16,055
That's about control, not speed.
82
00:04:16,083 --> 00:04:18,003
Let it dwell, but don't let it dry.
83
00:04:18,227 --> 00:04:23,443
Then rinse methodically from the top down,
with plenty of low pressure fresh water,
84
00:04:23,603 --> 00:04:27,603
to flush away the dead biological matter
and any chemical salts.
85
00:04:27,625 --> 00:04:30,185
And finally, test patch discipline.
86
00:04:30,313 --> 00:04:34,185
Pick an inconspicuous spot, and don't
judge it wet.
87
00:04:34,345 --> 00:04:37,465
Inspect it only after it's fully dried
down.
88
00:04:37,545 --> 00:04:41,705
That's when you see colourfastness, and
how the substrate really reacts.
89
00:04:41,708 --> 00:04:44,588
When you talk to customers, describe it as
asset preservation,
90
00:04:44,628 --> 00:04:45,708
not a fast jet wash.
91
00:04:45,868 --> 00:04:49,548
We're talking about a render facade that
can easily be worth fifteen thousand pounds
92
00:04:49,575 --> 00:04:49,948
or more.
93
00:04:50,038 --> 00:04:54,028
Knowing the substrate chemistry is what
separates a trained operator from a cowboy
94
00:04:54,048 --> 00:04:54,908
who ruins it.
95
00:04:54,917 --> 00:04:58,677
Podcasts like this are a great starting
point, but if you're serious about offering
96
00:04:58,741 --> 00:05:03,077
softwashing professionally, the CPD
Certified Softwash Training Course at
97
00:05:03,125 --> 00:05:08,357
softwashing.uk goes much deeper into
chemical selection, surface identification,
98
00:05:08,460 --> 00:05:10,997
safety and real world application.
99
00:05:11,197 --> 00:05:15,317
You learn at your own pace online, and you
can become an Approved Softwash
100
00:05:15,377 --> 00:05:19,637
Applicator, with a directory listing and a
place in the National Association of
101
00:05:19,717 --> 00:05:20,837
Softwash community.
102
00:05:20,875 --> 00:05:22,235
So here's your challenge.
103
00:05:22,363 --> 00:05:28,235
Next monocouche job, take photos of every
crack and repair before you touch it.
104
00:05:28,355 --> 00:05:29,355
See what you find.
105
00:05:29,542 --> 00:05:33,515
Until next time, stay safe and keep
cleaning smarter.
00:00:00,080 --> 00:00:01,660
Here's a scenario I want you to picture.
2
00:00:02,400 --> 00:00:06,020
You've just finished a lovely softwash on
a cream monocouche wall.
3
00:00:06,640 --> 00:00:08,340
It looks fantastic while it's wet.
4
00:00:08,900 --> 00:00:11,660
You pack up, the customer's happy, and you
drive off.
5
00:00:12,460 --> 00:00:13,840
Then the wall dries.
6
00:00:14,520 --> 00:00:17,860
And suddenly there's a square patch, about
the size of a dinner plate,
7
00:00:18,220 --> 00:00:21,380
that's a completely different shade from
everything around it.
8
00:00:22,740 --> 00:00:25,000
That's the day a clean becomes a dispute.
9
00:00:25,042 --> 00:00:29,442
I'm Mark Cave from SoftWash UK, and today
we're talking about monocouche render.
10
00:00:29,538 --> 00:00:32,882
What the risks are, and how a professional
works around them.
11
00:00:32,917 --> 00:00:34,037
First, what is it?
12
00:00:34,217 --> 00:00:36,997
Monocouche is French for single coat.
13
00:00:37,157 --> 00:00:42,117
It's a pre-mixed, cementitious, mineral
based render, and the key thing is that the
14
00:00:42,177 --> 00:00:44,037
pigment runs all the way through it.
15
00:00:44,197 --> 00:00:46,278
It isn't paint sitting on the surface.
16
00:00:46,457 --> 00:00:49,797
You'll know the big names, Weber, Parex, K
Rend.
17
00:00:49,897 --> 00:00:53,877
You'll see it on loads of modern UK
housing developments and commercial buildings.
18
00:00:53,917 --> 00:00:58,877
It usually has a scraped or textured
finish, and it's open and breathable.
19
00:00:58,973 --> 00:01:00,237
That's great for the building.
20
00:01:00,357 --> 00:01:05,357
But that open, capillary texture holds
moisture, airborne spores and pollution.
21
00:01:05,544 --> 00:01:10,157
So on damp or sheltered elevations you get
green algae, red or orange algae,
22
00:01:10,257 --> 00:01:11,917
and black organic growth.
23
00:01:12,029 --> 00:01:14,397
That's why we get called out to it so
often.
24
00:01:14,417 --> 00:01:15,137
Now, the risks.
25
00:01:15,228 --> 00:01:17,137
Number one is pressure.
26
00:01:17,497 --> 00:01:20,897
I still see people reach for a pressure
washer, or a hard tip,
27
00:01:20,927 --> 00:01:22,897
because the wall looks tough.
28
00:01:23,164 --> 00:01:24,177
It isn't.
29
00:01:24,305 --> 00:01:28,977
High pressure can score and etch the
surface, expose the aggregate underneath,
30
00:01:29,017 --> 00:01:31,217
and blow hollow or blown sections off.
31
00:01:31,397 --> 00:01:32,897
And here's the nasty bit.
32
00:01:33,037 --> 00:01:36,417
The wand stripes often only show once the
wall has dried.
33
00:01:36,630 --> 00:01:40,817
So you can walk away thinking you've done
a great job, and find out later you
34
00:01:40,857 --> 00:01:41,537
haven't.
35
00:01:41,542 --> 00:01:43,382
Number two is metal.
36
00:01:43,446 --> 00:01:47,142
This connects back to what we covered in
the episode on why bleach fails on rust
37
00:01:47,188 --> 00:01:49,702
stains, and the earlier render care
episodes.
38
00:01:49,782 --> 00:01:54,422
Biological staining clears with a gentle
oxidiser like sodium hypochlorite.
39
00:01:54,529 --> 00:01:56,502
Metallic runoff doesn't.
40
00:01:56,646 --> 00:02:02,102
Rusting screws, unpainted brackets,
satellite mounts, copper or lead flashings,
41
00:02:02,182 --> 00:02:05,382
overflow pipes, they all leach into the
render.
42
00:02:05,482 --> 00:02:10,822
Because monocouche is porous and cement
and lime based, that staining goes deep.
43
00:02:10,913 --> 00:02:13,733
If you blast it with hypochlorite, it
won't lift an iron stain,
44
00:02:14,113 --> 00:02:16,813
and it can leave an oxidised, shadowy look
around it.
45
00:02:17,693 --> 00:02:21,993
The usual answer is a targeted acid
treatment, something like oxalic acid.
46
00:02:22,573 --> 00:02:23,753
But be really careful.
47
00:02:24,253 --> 00:02:28,693
Strong acids can etch or react with the
cementitious binder and any limestone
48
00:02:28,773 --> 00:02:29,713
aggregate in the mix.
49
00:02:30,353 --> 00:02:34,813
So it's a test patch first, always, and
it's controlled, never a flood of acid
50
00:02:34,853 --> 00:02:35,513
across the wall.
51
00:02:35,750 --> 00:02:39,030
Number three is something customers never
see coming.
52
00:02:39,101 --> 00:02:40,910
Previous repairs.
53
00:02:41,040 --> 00:02:45,270
Monocouche walls often have hairline
cracks that were filled years ago,
54
00:02:45,323 --> 00:02:49,830
or patches done with unpigmented mortar,
mastic, or a different batch of render.
55
00:02:49,990 --> 00:02:53,510
When the wall's dirty, everything looks
evenly dull.
56
00:02:53,630 --> 00:02:58,630
Clean it, and suddenly you've exposed
batch banding and ugly repair patches.
57
00:02:58,730 --> 00:03:01,590
You didn't cause them, but guess who gets
the blame?
58
00:03:01,718 --> 00:03:04,950
That's why you document everything before
you start.
59
00:03:04,958 --> 00:03:07,358
Number four is strength and drying.
60
00:03:07,406 --> 00:03:11,198
Over concentrated hypochlorite, or letting
an alkaline solution dry quickly on a
61
00:03:11,262 --> 00:03:16,398
warm wall, can cause salt crystals,
surface chalking, or accelerated pigment fading.
62
00:03:16,518 --> 00:03:17,758
The rule is simple.
63
00:03:17,865 --> 00:03:19,998
Never let chemical dry on the substrate.
64
00:03:20,126 --> 00:03:22,720
Work in sections, and keep an eye on the
weather.
65
00:03:22,750 --> 00:03:24,350
So what does good practice look like?
66
00:03:24,510 --> 00:03:27,150
Start with a survey and photographs.
67
00:03:27,264 --> 00:03:32,190
Before any water or chemical goes near the
wall, record the hairline cracks,
68
00:03:32,217 --> 00:03:37,630
chipped corners, rust tails under vents
and fixings, and any previous patch repairs.
69
00:03:37,830 --> 00:03:40,110
Tap the wall to check for blown render.
70
00:03:40,243 --> 00:03:42,990
If it sounds hollow, say so, and record
it.
71
00:03:43,000 --> 00:03:44,120
Next, protection.
72
00:03:44,376 --> 00:03:49,480
Mask delicate aluminium trims, galvanised
brackets and lead flashings.
73
00:03:49,680 --> 00:03:54,360
Pre-wet the plants, the lawn and the
borders below so they're not taking the hit.
74
00:03:54,375 --> 00:03:56,135
Then apply the chemistry at low pressure.
75
00:03:56,315 --> 00:04:00,455
For monocouche, a controlled mix is
typically somewhere between one and a half and
76
00:04:00,495 --> 00:04:04,375
two and a half percent applied sodium
hypochlorite, with a bleach stable wetting
77
00:04:04,423 --> 00:04:08,295
surfactant such as Clever Wash, so it
clings to the wall instead of running straight
78
00:04:08,375 --> 00:04:08,775
off.
79
00:04:08,995 --> 00:04:13,175
Use a dedicated low pressure system, like
a twelve volt pump or a calibrated
80
00:04:13,235 --> 00:04:13,815
Dosatron.
81
00:04:13,911 --> 00:04:16,055
That's about control, not speed.
82
00:04:16,083 --> 00:04:18,003
Let it dwell, but don't let it dry.
83
00:04:18,227 --> 00:04:23,443
Then rinse methodically from the top down,
with plenty of low pressure fresh water,
84
00:04:23,603 --> 00:04:27,603
to flush away the dead biological matter
and any chemical salts.
85
00:04:27,625 --> 00:04:30,185
And finally, test patch discipline.
86
00:04:30,313 --> 00:04:34,185
Pick an inconspicuous spot, and don't
judge it wet.
87
00:04:34,345 --> 00:04:37,465
Inspect it only after it's fully dried
down.
88
00:04:37,545 --> 00:04:41,705
That's when you see colourfastness, and
how the substrate really reacts.
89
00:04:41,708 --> 00:04:44,588
When you talk to customers, describe it as
asset preservation,
90
00:04:44,628 --> 00:04:45,708
not a fast jet wash.
91
00:04:45,868 --> 00:04:49,548
We're talking about a render facade that
can easily be worth fifteen thousand pounds
92
00:04:49,575 --> 00:04:49,948
or more.
93
00:04:50,038 --> 00:04:54,028
Knowing the substrate chemistry is what
separates a trained operator from a cowboy
94
00:04:54,048 --> 00:04:54,908
who ruins it.
95
00:04:54,917 --> 00:04:58,677
Podcasts like this are a great starting
point, but if you're serious about offering
96
00:04:58,741 --> 00:05:03,077
softwashing professionally, the CPD
Certified Softwash Training Course at
97
00:05:03,125 --> 00:05:08,357
softwashing.uk goes much deeper into
chemical selection, surface identification,
98
00:05:08,460 --> 00:05:10,997
safety and real world application.
99
00:05:11,197 --> 00:05:15,317
You learn at your own pace online, and you
can become an Approved Softwash
100
00:05:15,377 --> 00:05:19,637
Applicator, with a directory listing and a
place in the National Association of
101
00:05:19,717 --> 00:05:20,837
Softwash community.
102
00:05:20,875 --> 00:05:22,235
So here's your challenge.
103
00:05:22,363 --> 00:05:28,235
Next monocouche job, take photos of every
crack and repair before you touch it.
104
00:05:28,355 --> 00:05:29,355
See what you find.
105
00:05:29,542 --> 00:05:33,515
Until next time, stay safe and keep
cleaning smarter.
