A major conservation effort at Charles Rennie Mackintosh’s Hill House in Helensburgh has hit a key milestone, the roughcast that contributed to long-running moisture problems has now been removed.
The house, completed in 1904, has taken the brunt of driving rain on Scotland’s west coast for more than a century. Early in the building’s life, a Portland cement render was applied under Mackintosh’s direction when it was widely viewed as a reliable shield against the weather. Instead, the roughcast trapped water within the walls, and water penetration gradually damaged both the structure and the home’s custom interior finishes.
To stop the deterioration and give the building a chance to dry, the National Trust for Scotland completed a large steel “box” around the property in 2019. With that protective enclosure in place, specialist stonemasons spent the past five and a half months carefully stripping the roughcast from the exterior, clearing the way for the next phase of work focused on making the building watertight and protecting it for the future.
For mason contractors and restoration crews, the Hill House story is a clear reminder that in exposed climates, surface treatments matter as much as the wall itself. When an exterior finish holds moisture in the masonry, the damage can show up for decades in places you cannot easily see. Projects like this also underline the value of phased work, ongoing monitoring, and trade expertise when the goal is to preserve historic fabric rather than simply replace it.
Next, the conservation team will work with experts to develop a long-term replacement roughcast that fits Mackintosh’s original design intent while better protecting the building envelope. The work is part of the National Trust for Scotland’s Mackintosh Illuminated project, with the Trust aiming to raise 14 million pounds toward the project’s 20 million pound cost.
Read the full, original article from The Scotsman here.