Facing the future

There are many benefits to building with Architectural Facing Masonry (AFM) blocks. as Steve Frost of Lignacite explains

Designed for internal and external applications, Architectural Facing Masonry blocks combine an inherent decorative appeal with strength and durability. Used for many years in construction projects around the UK, they have been used to construct walls, floors and interior finishes on homes, schools, factories and offices. They are one of the most sustainable and long-lasting building products available with many different textures from clean flat surfaces, to heavily textured and irregular faces, to stunningly beautiful polished masonry.

Aesthetics aside, building with facing blocks offers a number of benefits including structural strength and durability, sound control, fire protection and energy efficiency. Laying one standard block to six bricks shows construction savings too. Maintenance costs are reduced, as moisture, for example – which can undermine other building materials – has no adverse or weakening effect on concrete. The blocks are also not subjected to large daily temperature fluctuations, having a positive effect on ventilation, heating or air conditioning.

Due to the increasing demand for more ‘environmentally friendly’ products, manufacturers are constantly searching for new and improved methods of production. These include processes such as the refinement of raw materials and the use of greater quantities of recycled materials such as glass, shells and flint and selected secondary aggregates. As a result, it is now possible to find facing blocks containing in excess of 75 per cent recycled materials.

The cost of building materials such as natural stone can be a prohibitive factor facing architects and designers. Research and development within the concrete block industry has led to the creation of a number of man-made alternatives which closely replicate these natural products, while showing cost savings and environmental benefits.

An example of this can be seen on some of the recent phases of the Royal Wharf housing development in London, E16.

Today’s blocks are generally manufactured to a standard 440 mm x 215 mm face size, however smaller, lighter and more contemporary formats are now available. A good example of this is the ‘Roman Brick’ format which is 440 mm x 65 mm. This module has the length of a standard block but the height a standard brick. Having all the benefits and flexibility of a brick and only weighing 6 kg, it makes an attractive alternate to brickwork or conventional facing blocks. This provides savings in both material cost and labour, giving architects and designers the opportunity to design modern buildings which can blend into more traditional settings.

Facing masonry shapes are a simple and effective way of adding character to buildings, while providing solutions to some technical and aesthetic issues. Shapes are normally available in a range of standard units including quoins, cill blocks, trough lintel blocks and jamb blocks. Few manufacturers can offer full length hand cast versions of these shapes together with design and bespoke manufacturing services.

Different manufacturing techniques are used to achieve a varied range of finishes and textures. Smooth or natural masonry is produced straight from a mould and is best suited to situations where clean crisp lines are required in conjunction with monotone colours. Enhanced visual effects can be created by using bands of different textures and colours. This may be particularly desirable where wall heights span several stories.

Splitting blocks creates a craggy and heavily textured look producing a decorative masonry finish. Shot blasting exposes the natural aggregates within the block, producing a flat but weathered texture.

Polishing a block produces a high gloss finish with a shine that is both lustrous and distinctive while creating further visual interest by exposing the raw materials beneath the surface.

Stone faced masonry offers designers the opportunity to use high quality natural stone, normally granite and marble, in a conventional facing block manner with a bed of mortar, in a very cost-effective way. 10 mm slips of stone are bonded onto a dense concrete backing block. The bonding process uses the latest construction adhesive technology which has been rigorously tested for shear resistance and bonding. In addition, the finished product has been subjected to fire resistance and freeze/thaw testing.

A broad colour palette of blocks is available, created with the use of pigments and coloured raw materials. The most common are the earthy or natural tones such as sandstone or terracotta.

Facing masonry blocks are extremely versatile. They are available in a wide variety of colours, textures and formats and offer good design flexibility. Additionally, use of blocks creates both unique and stunningly visual impacts on buildings and in a cost-effective manner.

Steve Frost is head of sales & marketing at Lignacite