Blog posts of '2026' 'November'

The price of a bucket only tells you part of what a silicone render job will cost. Before putting a figure together, you need to know what it covers, what is going underneath it and how much material the job will actually use.

I’d start with the specified system and work through each component. That makes it easier to compare costs properly and spot anything missing before the order goes in.

This guide focuses on silicone thin coat systems. Bagged silicone-enhanced renders have different coverage and application requirements, so they need their own calculations.

Start with the system you’re pricing

Two jobs with the same wall area can need very different material budgets. A suitable, level background is a different starting point from an elevation that needs repairs, levelling or a specified build-up over insulation.

Before calculating quantities, confirm the substrate, its condition and the complete system specification. Depending on the job, your order might include preparation products, base coat, reinforcing mesh, primer, silicone finish, beads and fixings.

If insulation or render carrier boards are involved, include those and their associated components separately. A finishing-system price should not accidentally become the price for the whole wall build-up.

Our guide to choosing the right premixed render covers the product-selection considerations. Once that is settled, you can work out what needs ordering.

Measure the area and the details

Start with the area that will receive each material. Deduct openings where appropriate, then account for window reveals, door returns and any other surfaces included in the work.

I’d keep a separate record of linear measurements for beads and trims. Wall area alone will not tell you how many corners, stops or opening details you need.

Mesh needs its own calculation too. Allow for the specified overlaps and any additional reinforcement around openings or junctions. A roll’s nominal area is not necessarily the wall area it will cover once installed.

Any levelling work should also be measured and priced separately. Otherwise, extra base coat can disappear into the background before you have even started the specified reinforcing layer.

Turn coverage rates into quantities

Use the current technical data sheet for the exact product and finish you are ordering. Check the units carefully: a figure in kg/m² is different from one in kg/mm/m².

For a product with consumption stated in kg/m²:

Wall area × consumption rate = material required in kilograms

Divide that figure by the pack size, include an appropriate allowance for the job and round up to whole packs.

Where consumption is stated per millimetre of thickness, the specified thickness needs to be included in the calculation. Do not apply the same calculation blindly across base coats, primers and finishes.

For example, K Rend lists approximate consumption for Silicone TC 15 at 2.5kg/m², equivalent to around 10m² per 25kg bucket. That is a product-specific starting point, rather than a coverage rate for every silicone render.

A worked example for the finishing coat

Take a measured finishing area of 100m² and a 25kg product with stated consumption of 2.5kg/m².

For this illustration, assume a 10% material allowance and a hypothetical price of £60 per bucket excluding VAT. These are example figures, not a Rendit quotation or a recommended allowance for every job.

That £6.60/m² covers the finishing material only. It does not include base coat, mesh, primer, beads, preparation, delivery or labour.

For the actual estimate, replace the assumptions with the chosen product’s coverage, the current price for the selected colour and an allowance appropriate to the site and application method.

Build up the complete material cost

Repeat the quantity calculation for each specified component, using its own coverage or measurement basis.

I’d keep the estimate in a simple schedule:

Multiply the rounded pack quantities by the current purchase prices, then add delivery and any separately required consumables.

This gives you a material total you can divide by the measured wall area. It also shows where the money is going, which helps when comparing suitable systems.

If you need to check the preparation stages, our render base coat or primer guide explains their different roles.

Account for pack sizes and ordering

Pack rounding can make a noticeable difference, particularly on smaller jobs. If the calculation calls for part of an extra bucket, the purchasing budget still needs to cover a full bucket.

Keep this separate from your wastage allowance so you can see what you have already allowed for. The same applies to mesh overlaps: do not unknowingly count them twice.

Check colour availability, lead times and delivery charges before finalising the estimate. Confirm any batch requirements for continuous elevations with the supplier. Running short can create more than an extra material bill if it interrupts the programme.

Turn the material estimate into a job price

Once the materials are costed, add your labour, access equipment, plant, protection, waste disposal, overheads and margin separately.

Be clear about whether prices include VAT, and record when supplier prices were checked. Your quotation should also identify what preparation is included and how unexpected repairs or specification changes will be handled.

I’d rather have those details written down at the start than try to explain an extra cost after work has begun.

If you need help checking the components before ordering, speak to the Rendit team. With the substrate, measured area and proposed finish confirmed, we can help you identify suitable products and check the material requirements for the job.

When you are looking at tired or patchy render, a fresh coat of paint can seem like the obvious answer.

It may be the right approach, but I would check the wall before choosing a colour. You need to know what the render is, whether it has been painted before and what condition it is in.

Choosing exterior render paint involves more than finding a shade you like. The paint needs to suit the surface, and any underlying problems need sorting before you start.

Does the render actually need painting?

First, think about what you want to improve. Is the colour uneven, has the finish become dirty or are you looking to change the appearance completely?

If the main problem is dirt or organic growth, suitable cleaning may be enough to improve it. I would assess the surface again once it is clean and dry before deciding whether to paint.

Where the render is sound but needs a decorative refresh, a compatible paint can be an option. However, painting should follow an assessment of the existing finish and the preparation it needs.

What should you check first?

Look over the whole wall, including around windows, doors, gutters and near ground level. Check for loose render, flaking paint, cracks and persistent damp patches.

If something is failing underneath, a new coating will not make it sound. You might improve the appearance temporarily, but the original problem still needs attention.

I would be particularly careful with cracks that keep returning or patches that remain damp. Find out what is causing them before deciding how to repair or coat the surface.

Does the type of render matter?

Yes. Different renders and existing coatings can have different requirements, so I would not assume that one masonry paint suits every wall.

Try to establish which render was used and whether it has already been painted or treated. Original paperwork or information from the installer can help.

If the render forms part of an external wall insulation system, check the system specification before applying another coating. Where you cannot identify the surface, speak to the manufacturer or technical supplier before ordering.

Which exterior render paint should you choose?

Start with the existing surface and what you want the paint to do. A general decorative refresh, uneven colour and hairline cracking are different situations.

Ecorend SP77 Silicone Masonry Paint is a silicone resin-based option designed to provide weather resistance while allowing water vapour to pass through. Ecorend lists several suitable backgrounds, including render and properly bonded existing coatings.

Webersil P Silicone Paint is another option for suitable render and masonry, including refreshing tired façades. Check Weber’s current guidance for the building and system, as it includes restrictions relating to building height and multi-occupancy use.

Baumit Silikon Color is a ready-to-use silicone resin façade paint. As with the other options, check its suitability for the existing render and any previous coating before deciding.

I would not treat these products as interchangeable simply because they are silicone paints. Preparation, application and substrate requirements still need checking for the product you choose.

What if the render colour is uneven?

Where the main issue is colour variation, Ecorend RP77 Equalising Paint is designed to help achieve a more even appearance on suitable render. Ecorend identifies monocouche render as a suitable substrate.

Before using it, establish why the wall looks patchy. Colour variation and persistent damp staining need different attention.

If you are matching an existing finish, check the colour information carefully. Rendit’s SP77 and RP77 product pages include colour-matching notes, particularly relevant when continuing work started with materials from another supplier.

Can paint cover cracks?

Some specialist coatings have crack-bridging properties. Bauer Kapalux Flex Crack Bridging Paint, for example, is an elastic coating designed for suitable surfaces showing hairline cracks, including old render.

That does not mean it is the answer to every cracked wall. The type and extent of the cracking need to fall within the product’s specification.

I would get larger, widening or recurring cracks assessed first. A flexible coating cannot make loose render sound or resolve the cause of movement.

How much preparation is needed?

The surface needs to be sound and free from anything that could affect adhesion. Loose coatings, dirt and organic growth should be dealt with using methods suitable for the existing render.

Check the chosen paint’s instructions for cleaning, repairs and drying requirements. Any repaired areas also need to be ready for coating before you continue.

Primer requirements can vary. One product may need a separate primer, while another may specify a particular first-coat treatment. I would follow the individual instructions rather than use the same preparation for every paint.

When should you paint exterior render?

Check the forecast alongside the manufacturer’s application guidance. You need suitable conditions while painting and during the drying period afterwards.

Rain, frost, high humidity and hot surfaces can all affect when the work should go ahead. Direct sunlight can also be an issue, even when the air temperature seems reasonable.

The limits are not identical across products. I would plan around the paint’s stated temperature, humidity and drying requirements rather than assume a dry afternoon is enough.

Check colours and quantities before ordering

Before placing your order, make sure you know:

• Which paint is suitable for the existing surface
• What preparation or primer is required
• The area you need to cover
• How many coats are specified
• Whether coverage is quoted per coat or for the complete application
• Which colour and finish you want

Texture and absorbency can affect how much paint you use. Check the coverage information for your chosen product and background rather than relying on a general estimate.

Where samples are available, review them before committing to the full order.

Choosing the right products for the job

Painting existing render starts with understanding the wall. Check its condition, identify the existing materials and choose a paint that suits the surface and the result you need.

It is much easier to establish the preparation and coating requirements at the beginning than to put problems right afterwards.

If you are unsure which exterior render paint to choose, speak to us before ordering. Details of the existing render, photographs and an approximate wall area will help us discuss the options with you.