Cement Render vs Silicone Render: An Honest Comparison

What each render is

Cement render — more accurately sand and cement render — is a mix of sharp sand, cement, water and often lime or a plasticiser, applied by hand in two or three coats: a scratch coat, sometimes a second coat, and a finish coat floated or textured to the required look. It’s hard and strong once cured. It’s usually painted with masonry paint, because the natural grey colour isn’t attractive and the paint adds some weather protection. Our cement and sand render page explains it in more detail.

Silicone render is a modern thin-coat system: a base coat with reinforcing mesh bedded into it, a primer, and a thin finish coat containing silicone resins and the colour. The finish is only a few millimetres thick, but it’s highly water-repellent, more flexible than cement and designed to be vapour-permeable, and the colour runs through it, so it doesn’t need routine painting. See our silicone render page, and our exterior rendering guide for how both fit among the other systems.

For generations, sand and cement was the default render in Britain: cheap, strong, quick to apply with local materials, and familiar to every plasterer. Huge numbers of post-war houses, extensions and repairs were finished in it, and it was also applied over older brick and stone houses — sometimes with unhappy results on solid walls. Thin-coat systems such as silicone avoid several of its known weaknesses: cracking, repeated repainting and poor performance on walls that need to dry out. Cement hasn’t disappeared, though, and it remains a sound, economical material for the right jobs.

Cement vs silicone at a glance

indicative Ballpark figures; your wall, access and region matter more than the system.

Up-front cost

Cement render is the cheapest render to put on. The materials are inexpensive and widely available, and it’s a familiar job for plasterers and renderers across the country. As an indicative guide, it typically costs around indicative £35–£60 per m².

Silicone render costs more, typically around £65–£95 per m². The extra goes on the more sophisticated materials — mesh, primer and the silicone finish coat — and the multi-stage application.

The gap between the two ranges is roughly indicative £30–£35 per m², so on an illustrative 100m² of wall the render element alone differs by something like £3,000–£3,500 — real money on day one. But the per-m² figures don’t tell the whole story, because cement render usually needs painting straight away and then repainting for as long as it’s on the wall. See our house rendering cost guide for the wider picture.

The whole-life cost: where the gap closes

This is the comparison that matters most, and the one quotes don’t show. A painted cement render needs repainting periodically to stay looking good and to keep its paint layer doing its job. Each repaint means masonry paint, labour and, on most houses, scaffolding or access equipment again. Over the life of the render, those repaints add up.

A through-coloured silicone render doesn’t need routine painting. Its maintenance is an occasional gentle clean on shaded or north-facing walls where algae can appear, which is a small job by comparison.

Put the two together over a couple of decades, and the recurring cost of repainting a cement render can close much of the up-front gap. Exactly how much depends on how often you repaint, the size and height of the house and whether scaffolding is needed each time. But for most homeowners planning to stay put, the cheaper render on day one is not the cheaper render over the time they’ll own the house.

Cracking: the key practical difference

Cement render is hard and rigid. Buildings move slightly all the time — with temperature, moisture and settlement — and a rigid render can’t move with them. The result is cracking, from fine shrinkage cracks as the render cures to wider cracks over time. Once a cement render cracks, rain can get in behind it, and in winter that water can freeze, expand and push the render off the wall. That’s why so many older cement renders are cracked, patched and blown in places.

Silicone render systems are more flexible, and the reinforcing mesh bedded into the base coat across the whole wall spreads stresses and resists cracking. It still needs a sound wall and good detailing around openings, but it’s far more forgiving of the small movements that crack cement.

Our guide to render cracking explains what different cracks mean and how they’re fixed.

Water repellency and breathability

Silicone render combines two properties: it’s strongly water-repellent, so rain beads and runs off the surface, and it’s designed to be vapour-permeable, so moisture vapour inside the wall can escape. That helps keep the wall drier over time.

Cement render isn’t strongly water-repellent. It absorbs some water and relies largely on its paint layer to shed rain, and a dense mix — especially under a non-breathable paint — slows the escape of moisture from the wall. On a modern cavity wall, that’s usually manageable. On an old solid wall, it can trap moisture in the masonry, contributing to damp and decay.

Older solid-walled houses

This is where the comparison becomes more nuanced. On historic solid-walled houses built with lime mortar, a dense cement render is often the wrong choice: it can trap moisture in soft brick or stone, leading to damp inside and spalling masonry behind the render. Damp and spalling on period homes are often linked to cement render added in later repairs.

A modern silicone system may be suitable on some altered older walls, but take specific advice and ask for the product’s technical data. On genuinely historic solid walls, the expected and often best choice is lime render, which is softer and more vapour-open than either. If your house is solid-walled, see our lime render cost guide before choosing between cement and silicone.

Maintenance compared

Cement render needs repainting periodically, and before each repaint, cracks need filling and any loose or blown areas repairing. Flaking paint, cracks and staining are the usual signs it’s due. Between repaints, keep gutters and downpipes clear and fill small cracks before water gets in.

Silicone render needs no painting. Check it occasionally, especially on shaded walls, and give it a gentle clean with a suitable render cleaner when algae or dirt appears — never a pressure washer. Keep gutters and sills in good order so water doesn’t pour down the face of the wall. Our guide to algae on render explains the causes and the method.

Appearance and colour

Cement render can be finished smooth, floated, textured or dashed, and painted in any masonry paint colour. It suits traditional looks well, and repainting lets you change colour easily. The downside is that paint fades, chalks, peels and shows cracks, so a painted render can look tired between repaints.

Silicone render gives a crisp, uniform, contemporary finish in a very wide range of through-coloured shades, from bright whites to deep anthracite, with a fine, even texture. The colour is consistent across the wall and doesn’t peel. You can’t change the colour as easily as repainting — though a new finish coat is possible — so choose carefully. Our silicone render colours guide has ideas.

Which lasts longer?

Both can last many years when well applied to a suitable wall. Cement render’s life is limited mainly by cracking and the damage water does once it gets in; with regular repainting and prompt crack repair, it can perform for a long time. Silicone render’s flexibility and water repellency mean it tends to stay sound and clean with much less intervention.

In both cases, the deciding factor is the quality of the preparation and application. A badly applied silicone system will fail sooner than a well-applied, well-maintained cement render, so the installer deserves as much scrutiny as the product. Our guide to how long render lasts covers the factors in more detail.

Repairs: where cement still shines

Cement render has one clear advantage: it’s easy to repair. A crack or blown patch can be cut out, patched in a compatible mix and repainted, and once the whole wall is repainted, a well-matched repair is usually hard to spot. That makes cement the natural choice for like-for-like repairs on existing cement-rendered houses.

Silicone render can be repaired too, but because it’s through-coloured, a patch may not match a weathered wall exactly, and the repair needs the full layered system. Our render repair cost guide covers typical prices and the colour-matching issue.

Does either improve insulation?

Neither standard render adds meaningful insulation on its own; both are thin finishes compared with the wall. If you want to improve the warmth of your home, both can be part of an external wall insulation system, where insulation boards are fixed to the wall and finished with a render. Insulated systems are typically finished with a thin-coat render such as silicone rather than traditional sand and cement.

Whichever you choose, re-rendering a large share of a wall can bring Building Regulations into play. In England, stripping render back to the masonry and re-rendering more than 50% of a wall, or more than 25% of the whole building envelope, normally means the wall should be upgraded thermally where that’s technically, functionally and economically feasible, and building control should be notified. Patch repairs and over-coating sound render don’t usually trigger it. Wales and Scotland have their own rules, so confirm with building control; our guide to building regulations for re-rendering explains more.

When each render makes sense

Cement render still makes sense for like-for-like repairs on an existing cement-rendered house; as a base or levelling coat beneath some modern finishes, where the system manufacturer allows it; on outbuildings, garden walls and garages where appearance and long-term maintenance matter less; where budget is the overriding factor and you’re comfortable with a repainting cycle; and where you want to change colour easily over the years. It’s usually not the best choice for a whole-house render on a home you plan to live in for many years, and it’s generally the wrong choice on historic solid walls.

Silicone is usually the better choice for whole-house rendering and re-rendering on modern cavity-wall homes; exposed elevations facing driving rain; shaded or north-facing walls prone to algae; anyone who wants a low-maintenance finish with no repainting; pale or strong colours you want to stay crisp; and walls with some movement or mixed substrates, where its flexibility and full mesh help.

It’s also a common way to end the repainting cycle on a house that already has a painted cement render, either by removing the old render or, where it’s sound, preparing it and applying a silicone system over the top.

Replacing an old cement render with silicone

Many homeowners comparing the two already have a painted cement render that’s cracking and needs repainting again. There are two routes. If the existing render is sound and well bonded, it can often be prepared — cracks repaired, loose paint removed, a base coat and mesh applied — and a silicone finish applied over the top. If it’s hollow, cracked across large areas or linked to damp, it needs to come off first, which typically takes the job to around indicative £100–£170 per m² all-in.

A specialist will tap the walls to find hollow areas and tell you which applies. Our re-rendering cost guide covers the removal route in detail.

A worked example over the long term

Take a hypothetical semi with an illustrative 100m² of wall. At the indicative per-m² ranges, the render element in sand and cement comes to around indicative £3,500–£6,000 and in silicone around £6,500–£9,500, before scaffolding and preparation, which cost much the same either way. On day one, cement looks cheaper by a few thousand pounds.

Add several repaints of the cement render over the years you own the house, each with access, crack filling, paint and labour, and the gap narrows; the silicone needs only occasional cleaning.

The exact figures depend on your house and how often you repaint, which is why we haven’t put a single number on it. But the pattern is consistent: the longer you plan to stay, the more the through-coloured option tends to win.

Three example scenarios

These illustrative examples show how the choice usually plays out on real house types.

A post-war semi with flaking painted cement render. The render is mostly well bonded, with a few cracks and a small blown patch by the back door, and the owners are tired of repainting. Once hollow areas are cut out and repaired, preparing the sound render and finishing in a silicone system over a mesh-reinforced base coat ends the repainting cycle without the cost of a full strip. If tapping reveals widespread hollowness, the plan changes to removal and re-render.

A detached garage and garden wall on the same property. Appearance matters less, the walls are small and sheltered, and budget is tight after the main house. A well-applied sand and cement render, painted, is a sensible economical choice here, and easy to patch later.

A Victorian solid-walled end terrace with an old cement render and damp patches inside the gable. This is where neither cement nor a standard silicone system is the automatic answer. The likely recommendation is removal and lime, or at least a specification chosen specifically for breathability — see our lime vs cement render comparison before deciding.

How each is applied

Cement render is usually applied by hand in two or three coats. The first, the scratch coat, is pressed into the wall and scored to give a key. A second coat may follow to build thickness and level the surface. The finish coat is then floated smooth, sponged, textured or dashed. Each coat needs curing time, and the whole render needs to cure before it’s painted. Mix proportions matter: a mix that’s too strong is more likely to crack, which is why many renderers add lime to soften it.

Silicone render starts with beads at corners, openings and the base, then a base coat with mesh bedded into it across the whole wall. Once cured, a primer goes on, followed by the thin silicone finish coat worked to a uniform texture. It’s a more technical system with more materials, but each layer is thinner.

Both are weather-sensitive: neither should be applied in frost or heavy rain, and both need protecting from very hot sun and drying winds while they cure.

Dark and strong colours

Dark colours behave differently on the two renders. On painted cement render, a dark masonry paint absorbs more heat from the sun, which adds to thermal movement in a rigid render that already tends to crack, and paint on sunny elevations will need renewing. On silicone render, darker shades are available as through-coloured finishes, and the system’s greater flexibility copes better with movement.

If you want a strong or dark colour such as anthracite, silicone is usually the more reliable choice. Some systems limit how dark you can go on a given wall, so ask your renderer about the specific product’s suitability for dark shades on the elevation in question.

Questions to ask and how to compare quotes

Put these to any renderer quoting either system: Which would you recommend for my walls, and why? Are my walls solid or cavity, and does that change your recommendation? If you’re quoting cement, what mix, and is painting included? If you’re quoting silicone, which system, and is mesh full-coverage? Can my existing render stay, or does it need to come off? What guarantee comes with each option? The answers should be specific to your house, not a general preference. Our full list of questions to ask a renderer covers the rest.

When the quotes arrive, check each covers the same walls, preparation, beads and scaffolding, and that the cement quote includes the first coat of paint — a smooth or floated cement render usually isn’t finished until it’s painted. Ask the silicone quote to name the system and confirm full mesh. Our guide on how to get accurate rendering quotes has a full checklist, and our render guarantees guide explains what cover to look for on each.

When neither might be right

On historic solid-walled houses, lime is often the right choice rather than either. If your brickwork is sound and attractive, re-pointing may be all it needs — see our guide on whether to render or re-point. And if appearance is the main concern on an existing render, some homeowners compare masonry wall coatings too, a different product worth weighing on its merits.

If you’d like expert advice, SmartMatch™ weighs render-type experience, verified reviews, online reputation, insurance and accreditation to introduce you to one vetted local specialist for a free, no-obligation survey and quote. Browse every system on our services page.