I love that our house is constructed from stone hewn from the ground just metres away. The original mortar and plaster would have been similarly local, from kilns next to the ancient quarry that were used as far back as Roman times, perhaps further – people have been using fire and water to unmake and remake limestone in new forms with new properties since at least the Neolithic.
We’ve known for some time that cement used in a 1980s repointing job was trapping water and “rotting” our walls, and it’s high time we did something about it, so I’ve booked the whole family on a lime-pointing workshop in Dewsbury.
Our teacher, Ian Womersley, guides us through processes and techniques that have changed little in four millennia. We learn that adding water to raw quicklime creates a powerfully exothermic reaction, but left to slake for days or weeks, it matures into a beautifully malleable putty. Both the hotlime (activated quicklime) and putty make excellent mortars, but are slow to cure, so most people opt for natural hydraulic limes, prehydrated and premixed with sand, which can be activated with a little more water into a workable mortar that sets in a couple of days.
We spend an hour mixing and pushing various mortars into joints, while Ian punctuates his instructions with some of the many virtues of lime: “It’s porous, breathable, sustainable and strong; it literally draws damp out of your walls; if it cracks, it self-heals as rain gets in there and reactivates the lime; you can even reuse it after hundreds of years, just rake it out, crush it and add it to the new mortar; lime-mortared buildings can be dismantled rather than demolished as the bricks or stone are easily cleaned up and reused; honestly, I wonder why we ever thought of using anything else.”
Our efforts look amateur and smeary at first, but then comes the good bit – bashing the mortar as it dries with a stiff-bristled churn brush. The excess falls away, cracks and wrinkles magically disappear, and a square metre each of beautiful pointing is revealed. It seems almost too easy, until we remember that we have a whole house to do. But I can’t wait to see the results.
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