In fair-faced concrete the finish is not applied afterwards: it coincides with the first three millimetres of the pour. Everything the site does — the formwork, the release agent, the compaction — stays written on the wall forever.
It is the only material where structure and finish are the same gesture, made once and not repeatable. Quality is not born on site but in the preparation: the choice of formwork, which imprints texture and absorbency; the layout of joints and tie holes, which becomes the compositional module of the facade; the consistency of the mix, because two different deliveries give two different colours. The pour is then a matter of rhythm: shallow lifts, measured compaction, no interruption. After striking begins the part almost nobody really protects — moist curing, which decides how durable that skin will be and how uniform it will stay over decades.
click a beat · arrow keys ← → walk the site · dashed pauses are the chemistry at work
The detail of the craftcover as a countdown
Placing the cages on spacers made for fair-faced work, with increased cover and tie wires turned inwards.
Turn the tie ends inwards. Every wire pointing at the form is a stain three years from now.site notebook — editorial synthesis
Stains have a cause
Every imperfection in a fair-faced pour has a precise origin, and almost always one that predates the pour itself. Recognising them serves two purposes: correcting the next wall, and understanding where the responsibility lies before the discussion turns into a legal report.
A full-scale sample — a portion of wall built with the same forms, the same mix and the same team — is the tool that turns all of these items from disputes into agreed choices.
Three binders, three ways of thinking
Fair-faced concrete is no longer just Portland grey. UHPC pushes strength to values that allow extremely thin sections and shapes ordinary concrete cannot hold; geopolymer binders replace clinker with alkali-activated by-products, cutting the carbon footprint and changing both colour and chemical resistance. Each demands different formwork, timing and skills: they are not the same material with a different label.
A qualitative comparison between binder families, not commercial products. Performance and durability requirements remain those of the structural concrete standards: what is explained here is the logic of the choice, not a substitute for design values.
Only within narrow limits, and it is worth agreeing with the designer before trying. Isolated honeycombs are made good with shrinkage-compensated mortar of the same tone, sampled separately; blowholes are not filled one by one, because the result looks worse than the defect. Differences of tone can be softened with mineral glazes, never with opaque paint. A cold joint, on the other hand, cannot be removed: it can only be turned into a declared joint, by adding others at the same spacing so that it reads as a rhythm.
Because the colour of concrete depends on at least four variables that change from one pour to the next: the cement (even the same brand varies by batch), the water-cement ratio, the absorbency of the formwork and the curing temperature. That is why, on projects where tone matters, the cement batch is reserved, the mix is fixed and the whole facade is programmed to be poured with formwork at the same number of reuses. It is not fussiness: it is the only way to get uniformity.
It is a design decision, but technically they should always be closed at least on the inside: the tie tube is a direct passage through the wall and, if it crosses an element below ground or exposed to weather, it is a water path. Outside, coloured cement plugs are used, sampled on site, and they become part of the drawing. Leaving them open is legitimate only where there are no heated spaces behind the wall and the designer has decided so deliberately.
External fair-faced concrete and external insulation are incompatible by definition, so three routes remain. The first is a double-leaf cast wall with insulation between, poured in two stages or precast: it costs more and needs low-conductivity connectors. The second is internal insulation, which works but must be checked carefully for interstitial condensation and for the thermal bridges at the floor slabs. The third is to reserve fair-faced concrete for non-heat-losing elements — shear walls, parapets, walls of unheated spaces — and treat the envelope differently. None of the three is free: it has to be decided at design stage, not on site.