Why Modern British Homes Are Getting Mouldy

The recent push to retrofit insulation in Britain’s houses – slammed by green groups as the coldest and draughtiest in Europe – counterintuitively is likely to dramatically worsen living conditions, says Aris Roussinos in UnHerd. Here’s an excerpt:

Around 25% of Britain’s housing stock was built before 1919, the highest proportion in Europe. These houses were built according to time-tested techniques to manage the ambient moisture of Britain’s Atlantic climate through air flow – that is, the very draughts we now spend money attempting to eradicate. Air-permeable lime mortar between brick and masonry and lime plaster on the walls allowed moisture from within the home to evaporate outside, much like a high-tech wicking fabric. Draughty single-pane glazing allowed air to circulate, preventing the build-up of mould: the problem of heating draughty houses was efficiently solved by the simple, if now unfashionable expedient of burning vast amounts of wood, and later coal in open fires.

But after WWI, when many skilled tradesmen had been killed in the trenches, housebuilders adopted the newly-introduced solution of gypsum-brd plasters and cement mortar, as cheaper and quicker to work with. Because both are impermeable to moisture, houses began to be constructed with air cavities and external vents or air bricks for circulation. Over time, the old skills were lost, and houses built before 1919 – perhaps including yours – were renovated with impermeable gypsum plaster, and overlaid with non-breathable plastic-BRD paint.

Draughty windows were replaced with sealed double-glazing and chimneys were bricked up in favour of central heating, reducing air flow further. The result was an explosion of damp in British homes, and whole new industries of damp-proof courses and chemical injections – none of which work – aiming to resolve the newly-introduced problem. …

What’s the solution? Short of demolishing and rebuilding a quarter of Britain’s housing stock – often the most valuable and desired British homes – government grants wasted on introducing damp problems where they had never existed would be better spent on retraining tradesmen in traditional breathable techniques.

Worth reading in full.