Ventilation Blocks UK: Concrete & Terracotta 20x20x10 cm

In the UK trade these are called ventilation blocks, screen blocks or breeze blocks — pierced masonry units used for airflow, privacy and decorative screening. We cast them in Indonesia and ship FOB Semarang.

Minimum order: 1 × 20’ FCL — mixed items and sizes accepted, so you can load different blocks in the same container.

Two materials are available: concrete in a grey cement colour, and terracotta in a fired red clay colour. Both are 20 × 20 × 10 cm, so a single pallet plan works for either.

Ventilation blocks, screen blocks, breeze blocks — same product, three names

The naming differs by trade and by region. Builders' merchants in the UK usually advertise ventilation blocks when the purpose is airflow, screen blocks when the purpose is decorative screening, and breeze blocks when they mean lightweight concrete masonry in general. The unit we supply answers all three uses: it is a hollow, pierced block that lets air through while blocking sightlines.

Because the naming varies, please send the pattern you have in mind as a photo or drawing. We will confirm whether it matches a mould we already run, or whether it needs a new one.

Concrete ventilation block

Terracotta ventilation block

Specification

Unit size	20 × 20 × 10 cm
Coverage	25 pcs per m² (including joint)
Materials	Cast concrete (grey cement) · fired terracotta (red clay)
Typical unit weight	approx. 4.5 kg per piece (concrete)
Commodity code	6810.11 (concrete) · 6904 / 6905 (terracotta)
Terms	FOB Semarang, quoted per order

How many ventilation blocks per square metre

A 20 × 20 cm face with a 5 mm joint gives 25 blocks per square metre. A 10 m² screen therefore needs about 250 blocks; a 40 m² wall about 1,000. Allow an extra 5 per cent for cuts and breakages.

Because the blocks are pierced, the weight per square metre is lower than a solid block of the same size, which is what makes a full container economically sensible.

Container loading

Weight, not volume, is the limiting factor. On the assumption of 4.5 kg per piece, a 20ft container carries roughly 5,300 blocks — about 213 m². If your own unit weight differs, the figure moves: at 3.5 kg per piece you approach 5,900 blocks; at 5.5 kg you are nearer 4,300.

We will confirm the actual loading plan against the fired weight of your order before the container is booked.

Bringing ventilation blocks into the UK

As the importer you will need an EORI number and a customs agent who can classify the goods. Concrete ventilation blocks normally fall under 6810.11; terracotta units fall under heading 6904 or 6905 depending on whether they are building blocks or tiles. Your broker will confirm the final code and the duty rate that applies on the day of import, and import VAT at 20 per cent is normally recoverable if you are VAT-registered.

Documents we prepare for each shipment: commercial invoice, packing list, bill of lading, and a certificate of origin on request. If the consignment needs any additional declaration, please raise it at quotation stage rather than after the container has sailed.

Ports we quote to most often: Felixstowe, Southampton and London Gateway. Let us know which one your forwarder uses.

Colour and finish expectations

Concrete units are a consistent grey cement colour. Terracotta units are fired clay, so shade varies slightly between kiln batches — this is normal for the material, not a defect. If the screen is visible from one side only, we recommend ordering the whole area in a single batch so the tone stays even.

Order sequence: sample, pallet, container

Most UK merchants start with a sample box to check the pattern and the weight in hand, then a pallet for a trial installation, then a container once the product sells. We are happy to work in that order; it keeps your first commitment small and tells you how the block behaves on site before you invest in freight.

Tell us the pattern, the material, and the quantity you have in mind, and we will come back with an FOB Semarang quotation and the loading plan.

Frequently asked questions

Are ventilation blocks the same as breeze blocks?

In practical terms yes. "Breeze block" is the general UK trade term for lightweight concrete masonry; "ventilation block" or "screen block" describes a pierced unit used for airflow and screening. The blocks we supply are pierced, so UK buyers order them under either name.

What is the minimum order?

We quote from pallet quantities upwards and price per order. Sampling is possible before a production run is committed.

Can you match a specific pattern?

Send a photo or drawing of the pattern. If it matches a mould we already run, we can quote immediately; if not, we will tell you what a new mould would involve.

Do the blocks need UKCA marking?

That depends on how the blocks are specified for your project. Tell us at enquiry stage whether UKCA marking or test data is required, and we will confirm what can be supplied with the shipment rather than assume it.

Which UK ports do you ship to?

Felixstowe, Southampton and London Gateway are the ones we quote most often. If your forwarder consolidates elsewhere, send the details and we will price against that port.

Sourcing ventilation blocks for the UK?

Send the pattern, the material and the quantity you need — we will reply with an FOB Semarang quotation and a loading plan.

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