Falling Damp

Niamh Riordan

‘The root of all evil is water. It dissolves buildings’ Stewart Brand

A brick building is built in portable units: hand sized.  These bricks if made by hand were kneaded like bread before moulding. All that solidity was once wet dirt, but then dirt is the planet’s most popular of building materials.

Granby terraces come in red and buff.  Red and mottled mudstone dug out of Merseyside usually fires red, but with the right iron content it can turn pale and creamy: an antidote to the red brick snobbery which considered bright red buildings ‘fiery and disagreeable to the eye.’

All buildings have their private face, and underneath their plaster coats some walls are so piecemeal they’re practically collaged. Victorian mortar was lime based and often more brick spacer than adhesive. A builder trying to skimp on cost might skimp on lime, substituting in vegetable soil or dust from roads or the contents of ash pits. Gaps between bricks were stuffed with offcuts of wood, paper or fabric.  But terraced houses help support one another.

Tear down a Victorian wall and you will find horse hair, mixed in with lime plaster for its fibrous strength:  a prototype of the fibres and shreds now used for strength and insulation. One Granby Street resident suspects that her ‘60s estate was built with Weetabix. Her cavity walls are probably filled with fibreglass, blown in loose-fill insulation or spray foam.  Because air is increasingly a building material too – we construct with bubbles and pockets: holes poked in bricks to save clay and keep out moisture, lightweight hollow breeze blocks, aerated concrete, cavities filled with foamed petrochemicals.

Smeared in a smooth layer of plaster, a wall presents an inscrutable face. Victorians used lime plaster: caustic cousin of quick lime applied by labourers with weak acids on hand to treat the chemical burns. Plaster of Paris - the soft sulphate mineral Gypsum, roasted, powdered, mixed with water and when set, Gypsum once more - was cast for cornicing and ceiling roses: a pretty chunk of ceiling, replaceable when stained black by candle or gas-light smoke. The ‘Paris’ because Montmartre was once a Gypsum mine, though it’s now a hill full of holes.

Ceilings have thickened over the years, dropped false ones hiding bulky services and encasing another layer of air. But they started as the undersides of roofs, the smooth side of that most fundamental barrier. Ceiling, sealing: the two words are etymologically linked. All buildings obstruct outside elements to varying degrees, and a Victorian terrace is drafty -  air-tight is a 20th century invention, born of silicon sealants and mechanical ventilation. But every roof attempts to be a watertight obstacle to rain.

Water is the great corroder and our houses are soft at heart. The ‘universal solvent’, as Stewart Brand terms it ‘makes chemical reactions happen in every place you don’t want them.’ Stripping lead from terraced roofs is a reliable means of assuring dereliction. As rain enters buildings that have stood solidly for a century ‘it warps, swells, discolors, rusts, loosens, mildews and stinks.’ A house is nothing without its hat.

Niamh Riordan