A clinker brick facade ten years on

A facade is the one part of a building that everybody sees and that nobody replaces on a whim. The material is therefore worth discussing not on the day of purchase but at ten years' distance: how it looks by then, what a Vilnius winter does to it, and how it can be ruined without anyone meaning to.

What clinker is, and what it is not

A clinker brick is ceramic fired until the clay body partly vitrifies. That leaves it denser than an ordinary ceramic brick, with low water absorption and high resistance to freeze–thaw cycling. The second fact matters more than any technical figure: the colour of clinker is in the body of the brick, not in a coating over it. Scratch a clinker brick and the scratch is the same colour. Scratch a painted surface and you see what is underneath.

Decorative render is a different decision, not a worse one, but it follows another logic. It is a thin layer over an insulation system. It is sensitive to impact, it soils more readily, and on north and shaded elevations biological growth settles into it as grey and greenish patches. Render is repaired in patches, and a patch almost never matches the surrounding plane, so eventually the whole wall is repainted. That is a foreseeable and normal part of a rendered facade's life; it simply has a cost and an interval.

The third option, and the hardest to tell apart in a photograph, is a thin clinker slip glued to a substrate. The slips are real, from the same clay, but they are a finish rather than masonry. What decides the result is not the slip but the adhesive, the joint and the corner details. In masonry the corner is bonded; with slips the corner is assembled from a corner piece. Stand close to the corner of a finished building and you can see which it is. In a visualisation you cannot.

What water and frost do to a facade

At ten years the greatest risk to clinker masonry is not the brick. It is the joint and the flashings. Mortar is more porous than brick, so it takes the water first, and it is saturated mortar that freeze–thaw cycling tears apart. When a joint starts to dust, crumble or shift colour in particular bands of a facade, that is nearly always a story about where water runs, not about the quality of the masonry.

The path of the water starts at the top. Parapet flashings, window sill flashings, gutters and downpipes are the details that decide whether rain is led away from the wall or down it. If vertical streaks appear under sills and darker stains under the ends of flashings, the masonry is only the victim. That is why reading the facade of a finished building begins with the metalwork and not with the colour of the brick.

White bloom on new masonry deserves its own paragraph. It is efflorescence: salts carried out of the wall to the surface by water. In the first years it is ordinary, and rain and time usually wash it off by themselves. The bloom is not the problem; what matters is that it marks where the water travels. If the same spot is still white several years later, the question is not for the brick.

What never to do to clinker

Do not paint it. This is the first and most important point. A paint film closes the pores, water that has got into the wall has nowhere left to go, and the film starts to peel — beginning where it is wettest. Painted clinker is practically impossible to take back: stripping the paint damages the face of the brick with it. And in any case there is nothing to paint, because the colour is already in the body.

Do not pressure-wash into the joints. A joint is open to that kind of jet, and after a wash the facade has places with less mortar in them than before. Masonry can be cleaned, but with volume of water and angle, not with pressure.

Do not fill the cavity vents. Brick facades are often an outer leaf with a ventilated cavity behind them, and a cavity only works while air moves through it. The openings at the bottom and the top are not a bricklayer's oversight and not somewhere to be tidied up with mortar. Block them and the wall loses its ability to dry itself out.

Do not use acid cleaners without a test in a hidden place. Some products sold as masonry cleaners do not remove salts at all; they etch the surface and shift the colour of the brick unevenly. If cleaning is unavoidable, it starts on the least visible square metre.

How a clinker facade ages

Masonry built properly does not get lighter or darker across the whole plane over a decade. It becomes uneven. The south elevation reads slightly differently from the north, lighter bands appear under the flashings, a darker line forms at ground level, and in shaded corners the brick looks cooler. That is patina, and it is the reason a clinker wall at ten years looks older only in the ways it is worth looking older.

Over the same period a rendered wall has usually been washed or repainted at least once, and timber elements have either been renewed or deliberately left to grey. When several materials share one facade, their rates of ageing differ, and after ten years the building shows not only its design but how it has been looked after.

What a finished building shows

The building on Gerosios Vilties street in Vilnius is useful for this conversation because all three materials meet in one wall: dark clinker masonry, panels of beige render and timber battens at the balconies. It is built, handed over and lived in, so the materials there are a working facade rather than a set of sample boards.

At a wall like that you can walk up and look at the things no visualisation contains. The width of the joint and its tone against the brick — more of the character of masonry than the brick colour itself. The corner: whether it is bonded. How the brickwork meets the flashing and the window frame. Whether the plane runs flat along its full length or whether the light ripples across it. And the variegation of the brick itself: fired ceramic is never one colour, while in a render it always is, because there it is a texture.

The full-height glazed stair towers and the timber battens serve the same test. Glass shows how the immediately visible is maintained. Timber shows what the owners decided: left unoiled it greys over the years to a silvery tone, and that is not a fault but a choice — better known in advance than recognised five years in.

The building on Gerosios Vilties street was built by UAB Savo investicija (company code 304499183), part of the international SAVO group, which has been in the market since 2006. The choice of facade material here is a decision whose result can be inspected on foot rather than on a screen — which is how facades ought to be judged.