- How Much Area Does a 25kg Tub of Silicone Render Cover?
- How Do I Calculate How Much Silicone Render I Need?
- Example: 50m² Using 1.5mm Silicone Render
- Silicone Render Quantity Examples
- Make It Easier With Our Materials Calculator
- Does Silicone Render Grain Size Affect How Much I Need?
- What Is Silicone Render?
- What Else Do I Need With Silicone Render?
- Don't Forget Your Topcoat Primer
- Do I Need to Subtract Windows and Doors?
- Should I Order Extra Silicone Render?
- Can Silicone Render Be Applied Directly Onto Brick?
- How Much Does Silicone Render Cost?
- Frequently Asked Questions
- How many square metres does a 25kg tub of silicone render cover?
- How many tubs of silicone render do I need for 100m²?
- Is silicone render ready mixed?
- What thickness should silicone render be applied at?
- Can I use silicone render with external wall insulation?
- Calculate Your Silicone Render Requirements
If you're planning to silicone render a property, one of the first things you'll need to work out is how much silicone render you need.
Ordering too little can leave you short part-way through the job, while ordering considerably more than required can add unnecessary cost. The amount of render you'll need will depend mainly on the size of the area being rendered and the grain size you've chosen.
In this guide, we'll explain silicone render coverage, how to calculate the quantity you need and what other materials you may need to complete your project.
How Much Area Does a 25kg Tub of Silicone Render Cover?
Silicone render coverage varies depending on the grain size.
EWI Pro EWI-075 Silicone Render is supplied in 25kg tubs and is available in a choice of grain sizes. As a general guide, the expected coverage rates are:
|
Grain Size |
Approximate Coverage per 25kg Tub |
|
1.0mm |
12–13m² |
|
1.5mm |
9–10m² |
|
2.0mm |
7–8m² |
|
3.0mm |
5–6m² |
The grain size also determines the thickness at which the thin coat render is applied. For example, a 2mm grain silicone render should be applied at approximately 2mm thickness.
These figures should be treated as a guide. The condition and evenness of the substrate, application and wastage can all affect the amount of material used.
How Do I Calculate How Much Silicone Render I Need?
The basic calculation is straightforward:
Total wall area ÷ coverage per tub = number of tubs required
You'll need to begin by calculating the square metre area of the walls you're planning to render.
For a simple wall:
Wall width × wall height = wall area in m²
For example, a wall measuring 10m wide by 5m high would have an area of:
10m × 5m = 50m²
You can then divide this by the expected coverage of your chosen silicone render.
Example: 50m² Using 1.5mm Silicone Render
A 25kg tub of 1.5mm silicone render covers approximately 9–10m².
Using the more conservative 9m² coverage figure:
50m² ÷ 9m² = 5.56 tubs
Because you can't purchase part of a tub, you would need to round this figure up to 6 tubs.
It's usually better to calculate conservatively rather than risk running out of material during application.
Silicone Render Quantity Examples
For a quick idea of how much 1.5mm silicone render you may need, here are some example quantities based on approximately 9m² coverage per tub.
|
Render Area |
Approximate Number of 25kg Tubs |
|
25m² |
3 tubs |
|
50m² |
6 tubs |
|
75m² |
9 tubs |
|
100m² |
12 tubs |
|
150m² |
17 tubs |
These examples are intended as a starting point rather than a final material specification. Your project's substrate, detailing and application can affect actual consumption.
Make It Easier With Our Materials Calculator
Don't want to calculate every material individually?
Our Materials Calculator can help you work out the materials required for your project and provides a straightforward way to build your materials list. We also offers the option to receive a personalised quote based on the materials required.
Instead of only calculating your silicone render, you can use the calculator to consider the other components needed for your chosen system.
Click on the image below to give it a go.
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You can also check out our blog, which provides a step-by-step guide on how to use our materials calculator.Â
Does Silicone Render Grain Size Affect How Much I Need?
Yes. The larger the grain size, the more material you'll generally need to cover the same area.
For example, a 25kg tub of 1.0mm silicone render may cover approximately 12–13m², whereas a tub of 3.0mm silicone render may cover approximately 5–6m².
Your grain size isn't just a question of coverage. It also influences the finished texture of the façade.
When choosing a render, think about both:
-
The appearance you want to achieve
-
The quantity of material required for the project
If you're comparing finishes, ordering samples before committing to a colour and texture can help you make your final choice.
What Is Silicone Render?
Silicone render is a thin-coat decorative render designed to provide an attractive external finish while offering properties including breathability, flexibility and water repellence.
EWI Pro EWI-075 Silicone Render is a polymer-modified, ready-to-use render suitable for a range of applications, including external wall insulation systems and render-only systems. It can be used on suitable substrates, including brick, concrete, render carrier boards, and traditional plasters, when the correct preparation and system build-up are followed.
Its combination of performance and decorative finish makes silicone render a popular choice for both renovation and external wall insulation projects.
What Else Do I Need With Silicone Render?
The silicone render itself is only the final decorative layer of the system.
Exactly what sits underneath it will depend on the substrate and whether you're installing a render-only system or an external wall insulation system.
Depending on the project, the full build-up may include products such as:
-
A suitable basecoat
-
Fibreglass mesh
-
Render beads and profiles
-
Topcoat primer
-
Silicone render
-
Insulation, adhesive and mechanical fixings where part of an EWI system
It's important to consider the complete system when calculating quantities rather than simply working out how many tubs of topcoat you need.
Don't Forget Your Topcoat Primer
A suitable topcoat primer is applied before the silicone render as part of the appropriate system build-up. The primer helps prepare the surface ahead of the final thin coat finish. EWI Store's guidance for rendering onto brick, for example, specifies allowing the Topcoat Primer to dry before applying Silicone Render.
Do I Need to Subtract Windows and Doors?
When measuring the total façade, you'll naturally have areas such as windows and doors that won't be rendered.
These openings can be taken into consideration when calculating the total square metre area. However, you'll also need to remember that detailing around window and door reveals still requires material.
For straightforward projects, measuring each individual render area will give you a more accurate starting figure than simply using the property's overall width and height.
For buildings with multiple elevations, calculate each elevation separately before adding them together.
For example:
Front elevation: 45m²
Rear elevation: 42m²
Side elevation 1: 30m²
Side elevation 2: 30m²
Total = 147m²
You can then use this total area to estimate your silicone render requirement.
Should I Order Extra Silicone Render?
It's sensible to avoid ordering an amount that leaves no margin at all.
Small variations in substrate condition, application and wastage can change material consumption. Your calculated figure should therefore be considered an estimate rather than a guarantee that every project will use exactly the published coverage rate.
There is another important consideration with coloured render: batch consistency.
We recommend mixing tubs where necessary because colours from different batches can vary slightly. Tinted renders are also made to order, so checking your chosen colour with a sample before purchasing the full quantity is recommended.
For that reason, working out your total requirement before placing your order is particularly useful.
Can Silicone Render Be Applied Directly Onto Brick?
Silicone render can form part of a render system installed over suitable brickwork, but that doesn't mean the thin coat silicone finish should simply be applied straight onto an untreated brick wall.
The substrate needs the correct preparation and system build-up before the final silicone render is applied.
Our render-onto-brick guidance, for example, uses preparation and base layers before Topcoat Primer and Silicone Render are applied as the finishing stages.
Below is a list of products we recommend using; please read our guidance on render-onto-brick installations for advice on when to use each product and how. If you're unsure which system is appropriate for your substrate, speak to the EWI Store sales team before ordering your materials: 0203 0340 552
How Much Does Silicone Render Cost?
The total material cost of a silicone render project depends on much more than the number of tubs of topcoat required.
You'll need to consider:
-
Total façade area
-
Grain size
-
Substrate condition
-
Required preparation
-
Basecoat and fibreglass mesh
-
Primer
-
Beads and profiles
-
Insulation and fixings, where applicable
-
Number of silicone render tubs required
This is why calculating the whole system is generally more useful than looking only at the cost of a single tub of render.
Frequently Asked Questions
How many square metres does a 25kg tub of silicone render cover?
Coverage depends on grain size. As a general guide, we state approximately 12–13m² for 1.0mm, 9–10m² for 1.5mm, 7–8m² for 2.0mm and 5–6m² for 3.0mm.
How many tubs of silicone render do I need for 100m²?
Using 1.5mm silicone render and calculating conservatively at approximately 9m² per tub, 100m² would require approximately 12 x 25kg tubs.
Always check your project's exact requirements before ordering.
Is silicone render ready mixed?
EWI-075 Silicone Render is supplied as a ready-to-use thin coat render, removing the need to mix the render from a dry powder before application.
What thickness should silicone render be applied at?
Thin coat render thickness corresponds to the selected grain size. For example, we advise that if it's 2mm Silicone Render should be applied no thicker than approximately 2mm.
Can I use silicone render with external wall insulation?
Yes. EWI-075 Silicone Render is suitable for use as the decorative finish within appropriate external wall insulation systems and is highly breathable, making it suitable for systems using breathable insulation such as Mineral Wool or Wood Fibre.
Calculate Your Silicone Render Requirements
Getting the quantity right starts with knowing your total render area and chosen grain size.
Once you've calculated the square metre area of your project, you can estimate the number of tubs required using the coverage figures above. But remember that silicone render is only one part of the system.
For a quicker way to plan your project, use the EWI Store Materials Calculator to work out the materials you may require.
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