In short
- Silicone is a thin-coat system (1–2 mm topcoat over a meshed base); monocouche is a single 15–20 mm coat, scraped back.
- Silicone costs more, typically £60–£120 per m² against £55–£90 for monocouche in 2026.
- Silicone sheds water and resists dirt and algae better; monocouche is tough and good value on sound brick and block.
- Monocouche is more prone to lime bloom if applied in cold, damp weather.
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At a glance
| Silicone thin-coat | Monocouche | |
|---|---|---|
| Build-up | Base coat with mesh, primer, 1–2 mm topcoat | One 15–20 mm coat, two passes |
| Finish | Fine even grain, sharp edges | Scraped, lightly textured |
| Water behaviour | Strongly water-repellent, breathable | Water-resistant, breathable |
| Dirt and algae | Better resistance | More prone over time |
| Flexibility | Good, especially with meshed base | Rigid |
| Weather risk during application | Rain and cold delay curing | Lime bloom in cold, damp conditions |
| 2026 installed range | £60–£120 per m² | £55–£90 per m² |
| Suitable substrates | Brick, block, old render, boards, EWI | Sound brick and block |
Choose silicone if
- the wall already has render or pebbledash you plan to render over;
- the house is shaded, near trees or on a busy road;
- you want the lowest maintenance over the long term;
- you are adding external wall insulation;
- you want a very smooth, crisp modern finish.
Choose monocouche if
- the substrate is clean, sound brick or block, such as an extension or stripped wall;
- budget is a priority and the house is in an open, sunny position;
- you like the slightly textured scraped look;
- work can be scheduled in mild, dry weather.
The hybrid option
Several manufacturers sell silicone-enhanced scraped renders, such as K-Rend's K1, which sit between the two: a monocouche-style application with better water repellency. See K-Rend vs Weber.
What matters more than the choice
A well-applied monocouche will outperform a badly applied silicone every time. Beads, mesh at openings, render stopping above the damp-proof course, sill drips and weather-aware scheduling decide how a render ages. See choosing a rendering contractor.
Questions people ask
Does monocouche crack more than silicone?
Monocouche is more rigid, so it can crack where the substrate moves, but good detailing and mesh at weak points prevent most cracking. Silicone systems with a meshed base are more tolerant.
Which lasts longer?
Both commonly last 20 to 30 years or more. Silicone tends to look cleaner for longer.
Can monocouche be applied over old render?
It is best on clean brick and block. Over old render, a thin-coat silicone system with a levelling base is usually more appropriate.