What is cork render and how does it compare to other renders?

Cork render is a sprayed natural cork coating applied at around 6 to 8mm thick. It is unique among render systems in being fully breathable, thermally insulating, and able to be sprayed directly over existing pebbledash or render without removal. Silicone and cement renders are not breathable enough for old solid walls, and lime is breathable but does not insulate. Cork does all three.

Which render is best for a wet climate like Devon?

Silicone render. Devon's climate is mild and wet, which is ideal for algae and green growth on north-facing walls. Silicone render is water-repellent so rain beads off the surface rather than soaking in, while still letting the wall breathe. That combination keeps it cleaner for longer than monocouche or painted cement render.

Can you render over a cob or stone wall?

Not with cement or silicone render. Old cob, stone and solid-brick walls need to breathe, and sealing them with a modern impermeable render traps moisture inside the wall, causing damp and rot. Those properties need lime render, which is breathable and moves with the building.

Types of Render Compared | Silicone, Cork & Lime

Q: Which render is best for an old solid wall?

Lime or cork render. Both are genuinely vapour-open, allowing a solid cob, stone or brick wall to breathe. Silicone, monocouche and sand-and-cement renders all trap moisture inside a solid wall, causing internal damp and timber rot. Cork has the additional advantage of insulating a wall that has no cavity to fill.

Q: Which render is cheapest?

Sand and cement render is the cheapest to apply up front, but it must be painted and repainted roughly every five years, and each repaint means hiring scaffolding again. Silicone and monocouche are through-coloured and never need repainting. Over a twenty-year period silicone usually works out cheapest overall despite having the highest starting price.

Q: How long does render last?

A well-applied silicone render should last 20-30 years before it needs any recoating. Monocouche is similar in lifespan but may need crack repairs sooner. Painted sand and cement render lasts as long structurally, but the paint finish needs redoing roughly every 5 years.

Every system, side by side

Same wall, five very different jobs.

	Silicone / K-Rend	Cork	Lime	Monocouche	Sand & cement
Best for	Modern cavity walls	Old solid walls & pebbledash	Cob, stone, listed	New-build blockwork	Budget jobs
Breathable?	Yes, water-repellent but vapour-open	Yes, fully vapour-open	Yes, the most breathable	Partially	No, traps moisture
Safe on cob/stone?	No	Yes	Yes	No	No
Insulates?	No	Yes, up to 30% less heat loss	No	No	No
Needs painting?	Never, through-coloured	Never, coloured	Usually limewash	Never, through-coloured	Yes, every ~5 years
Goes over pebbledash?	Only if sound	Yes, sprays straight over	No	Only if sound	Only if sound
Cracking	Flexible, resists it	Flexible, 25-yr guarantee	Very flexible, self-healing	Prone to hairline cracks	Prone to cracking
Can be patch repaired?	Hard to colour match	Yes	Yes	Hard to colour match	Yes, just repaint
Green growth	Self-cleaning	Resistant	Weathers naturally	Holds dirt & algae	Depends on the paint
Lifespan	25–30 years	25+ years	Decades, if maintained	20–30 years	Long, but paint 5 yrs
Up-front cost	High	High	Highest	Middle	Lowest

Pebbledash is not really a system in its own right. It is a sand and cement render with aggregate thrown at it while wet. Everything in the cement column applies to it.

So which should you actually pick?

Modern cavity-walled house, and you want it done once? Silicone render. It costs the most up front, but it never needs painting, it shrugs off Devon's driving rain, and it doesn't go green on the north wall. Over twenty years it's usually the cheapest once you count the repainting you're not doing, and the scaffolding you're not hiring every five years to do it.

Old solid walls, or a pebbledashed house you're sick of looking at? Cork render. It's the only system that's fully breathable and insulating and sprays straight over what's already there. On a cold, solid-walled Devon house it does three jobs at once, and it's the one nobody round here is offering yet.

Cob, stone, or a listed building? Lime render. It's the traditional answer and on a listed property it's usually a requirement rather than a preference. Slow, skilled, expensive, and beautiful on the right building. Cork is a genuine modern alternative if you also want the insulation, but lime is what the building was built with.

Tighter budget, new-build blockwork? Monocouche. Through-coloured, durable, noticeably cheaper. Accept that you'll likely see the odd hairline crack, and that it collects dirt more readily than silicone.

Cheapest possible, and you don't mind the maintenance? Sand and cement, painted. Nothing wrong with it as a traditional render, but budget for repainting every five years, and know that it doesn't breathe, so it must never go near an old solid wall.

Common questions

The ones we get asked on every render quote.

What is cork render and how does it compare?

Cork render is a sprayed natural cork coating, around 6–8mm thick. It is unique in being fully breathable and insulating and able to spray straight over existing pebbledash or render. That combination doesn't exist in any other system, silicone and cement aren't breathable enough for old walls, and lime is breathable but doesn't insulate. More on cork render here.

Which render is best for an old solid wall?

Lime or cork. Both are genuinely vapour-open, so the wall can breathe. Silicone, monocouche and cement render all trap moisture in a solid wall, which causes damp inside and rot in the timbers. Cork has the added advantage of insulating a wall that has no cavity to fill.

What's the difference between silicone render and monocouche?

Both are through-coloured, so neither needs painting. The difference is flexibility and how they handle water. Silicone is a thin-coat system, roughly 6–8mm, and it's water-repellent but breathable. Monocouche is a thicker one-coat cement-based render, around 15–20mm, applied straight onto blockwork. Monocouche is cheaper and very durable but more prone to hairline cracking and holds dirt more readily.

Which render is best for Devon's weather?

Silicone. Our climate is mild and wet, ideal conditions for algae on a north-facing wall. Silicone render sheds rain from the surface while still letting the wall breathe, and the self-cleaning finish keeps it looking right for years longer than the alternatives.

Which render is cheapest overall?

Sand and cement is the cheapest to apply. But it has to be painted, and repainted every five years or so, and each repaint means hiring scaffolding all over again. Silicone and monocouche are through-coloured, so that cost never arrives. Over a twenty-year view, silicone usually works out cheapest despite the higher starting price.

Can you render over cob or stone?

Not with cement or silicone. Old walls need to breathe. Seal one with a modern impermeable render and the moisture gets trapped, which leads to damp inside and rot in the timbers. Those properties need lime render, which breathes and moves with the building.

How long does render last?

A well-applied silicone render should give you 20–30 years before it needs anything doing. Monocouche is similar but may want crack repairs sooner. Sand and cement lasts structurally, but the paint finish needs redoing roughly every five years.

Types of render compared