Technical Data

All Fireborn^® blocks are F2 durable (BS EN 771-1)

Ibstock Product Specification Clauses

  Click the relevant colour to download a product specification for Fireborn in PDF format.

Mortar Mix

For normal elevations a designation (ii) mortar mix (1:½:4½ cement:lime:sand) will be suitable when used at a stiff consistency appropriate for the weight of the units.

Pack Sizes

Fireborn blocks are packed on pallets with interleaving paper, shrinkwrapped and are Fireborn branded. Handling and laying instructions are included with each pack.

The above information does not apply to Glazed units.

Stack-bonded fireborn^®

With stack-bonded work, there is no cross bonding from course to course with a consequent reduction in flexural strength.

There are two ways of achieving stability, one way is to use Twin Block, which can be laid stretcher bond but looks like stack-bonding and the other is to use bed joint reinforcement.

Bed joint reinforcement is used to restore bond and stability and panel strength is calculated from the reinforcement specified.

Generally, bed joint reinforcement should be incorporated at 225mm vertical centres(i.e every course for 215mm high Fireborn), using stainless steel ladder type reinforcement, material ref. SBF35W60 by BRC Building Products, or similar. Care in setting out is required in ‘stack-bonded’ situations to ensure uniformity of vertical joints and some size selection will be beneficial.

Quality Control

Fireborn is individually gauged and batched. There are three size definitions ‘L’, ‘M’ and ‘H’ into which Fireborn is batched thus providing the tightest tolerances in the market.

For the 440mm block, a square gauge is used and the block has to fit precisely or it is rejected.

These are probably the tightest quality controls for size in the industry and means that for stack bonding there is no better product.

Each product is also colour checked against the Colourimeter, to ensure consistent and repeatable colour. This electronic device digitally measures the colour of the fired Fireborn block and this data is then compared to the agreed colour data to ensure minimal variation from standard.

Peacocking

Natural blue Fireborn sometimes exhibits an oily coloured type of stain,generally referred to as ‘peacocking’. It is caused by light diffraction through a very thin surface layer of colloidal silica and it is noticeable because of the iridescent effect of the blue colour.

The staining is usually a result of:-

• Saturation of brickwork prior to the mortar curing – giving a picture frame effect
• Fireborn coming into contact with copious amounts of water before being built in. The manufacturing process uses a layer of silica sand to separate the bricks during the firing process, without this the bricks would fuse together in the kiln. The residue of silica on the bricks can turn blotchy when saturated.
• Water run-off from cementitious areas
• A fine deposit of cement or lime transmitted to fine crazing lines by the moisture in the mortar at the time of laying.

All of the above are superficial; are not detrimental to the performance of Fireborn and all may be minimised by protection from saturation during construction. It is a natural phenomena of natural blue clay products and it should be expected to happen.

Laying Instructions

Health & Safety

Fireborn Glazed laying guidelines

Handling Fireborn

Fireborn Clay Laying Guidlines