Our conservation architect on breathable repair, and the damage cement has done since the 1970s.

When the first Huer’s Hut appeared on the lane above Porthminster, now known as Hain Walk, it would have been made of what the builders of it had to hand or materials available locally. There is no record of when the Huer’s Hut first appeared on the headland, but we know that the seining industry was thriving from records in 1736 with huers mentioned in roles.

The oldest material within the Huer’s Hut structure is on the rear wall, earth mortar and local stone. It seems likely that the majority of the building would have been constructed this way – earth mortar and stone laid on a shelf cut straight into the headland. Earth mortar, like lime, is breathable and when water that gets into the wall, whether from rain or damp ground, it can pass back out through it and evaporate. The wall works with the weather instead of fighting it. Older buildings were built in a way that ensured they were breathable and therefore long lasting.

However, in modern times, materials that aren’t breathable have been developed, and we start to see challenges arise, particularly in older buildings, where non breathable materials are mixed with those that need to breathe.

Cement for example, doesn’t work in the same way as earth mortar. Cement is hard, and it’s impermeable and where earth mortar lets moisture through, cement traps it – sealing water inside the wall instead of letting it out. That trapped moisture doesn’t sit still. It carries soluble salts through the stone, and when those salts reach the surface and crystallise, they push outward with force. The result is spalling – stone and mortar crumbling and flaking away from the inside out. It’s slow, and it’s easy to miss until the damage is well advanced – which is exactly what’s happened inside the Huer’s Hut.

The building’s own history has made this worse. When Sir Edward Hain funded the building of the south shelter in 1904, it appears that around the same time, ground behind the Huer’s Hut was raised, banked up against the rear wall of the hut. This rear wall has been soaking up moisture from that raised ground ever since. Add cement repairs on top of that, likely carried out in good faith during the 1970s, and you get a wall that’s been slowly trapping water against itself for decades.

En Space, the conservation architectural practice working alongside Lavigne Lonsdale, have advised that in order for the Huers Hut to have a long future, any modern material should be removed. This involves stripping out the inappropriate cement pointing, to repair with mortar that matches the original – earth and lime, breathable, working with the building rather than against it. It’s a slower, more careful way of repairing a wall. It’s also the only way of actually stopping the decay rather than just hiding it for another few decades.

Cement for example, doesn’t work in the same way as earth mortar. Cement doesn’t stop water getting into the wall, it just stops it getting back out.