Common Mistakes When Restoring a Garden Folly (and How to Avoid Them)

Follies are among the most forgiving buildings in Britain and among the least forgiving things to restore. A tower raised as a joke, a sham ruin built to close a view, a temple of brick dressed up as stone: they were never meant to be weathertight, practical or permanent. That is part of their charm, and the reason so many well-meaning repair projects go wrong.

The damage is rarely dramatic. A hard cement mortar here, a changed roof pitch there, a land drain that no longer runs anywhere, and a century of gentle decay becomes a decade of rapid decline. These are the mistakes that come up again and again, and how to sidestep them.

Assuming a folly was built like a house

Most follies are thin-walled, lightly founded and made of whatever was cheap: soft brick, rubble stone, rough core work, timber, render, plaster on lath. What weatherproofing they had was usually lime, which is soft, porous, and moves with the building rather than fighting it.

The classic error is to repair with whatever a modern builder carries in the van — ordinary Portland cement mortar, cement render, acrylic masonry paint, injected damp-proof courses, silicone, plastic gutter, modern screws driven into soft brick. These are hard, strong and impermeable. Moisture that used to evaporate is now trapped; salts crystallise; brick faces spall; cracks open along the line where old meets new.

The fix is to match, or at least respect, the original: lime putty or natural hydraulic lime for pointing, mixed weaker than the masonry it holds; limewash or a breathable mineral paint; lead, cast iron or timber gutters repaired rather than swapped for plastic; non-ferrous or stainless fixings in stone. If you cannot tell what the existing mortar is, have it analysed before a single joint is raked out. Then try a small test patch in an inconspicuous place through one winter before committing a whole elevation.

Over-restoration: making it better than it ever was

Follies owe much of their appeal to age and oddity. A blast of the pressure washer strips the fired skin from brick and leaves stone looking newly quarried. A neat rebuild of a ragged parapet deletes the evidence of time people came to see. It is possible to spend a great deal of money and reduce the building's interest in the process.

The usual culprits:

• Rebuilding a collapsed section to an invented design, or to "how it must have looked".
• Repointing every joint when only a fraction have failed, racking out sound fabric for nothing.
• Stripping vegetation wholesale, including ivy that may be holding a ruin together.
• Adding handrails, floodlights, benches, signage and glass — all of which change what the folly is.
• Straightening a leaning wall without understanding why it leans, or whether it has stood that way for a century.

Work to the principle of repair rather than restore, with minimum intervention and as much historic fabric kept as possible. New work should be honest and legible on close inspection rather than indistinguishable from the old. As for ivy: on a sound wall, remove it; on a fragile ruin it may be structural, in which case cut it at the base and let it die back slowly instead of tearing it off in an afternoon.

Ignoring water, the thing that actually kills follies

Follies rarely fall down. They rot, spall and settle because water gets in and cannot get out. Blocked gutters and hoppers are the most common culprit, followed by downpipes discharging straight against the wall and ground levels that have crept up over the base, burying the plinth. Shallow roof pitches, hidden valleys and a lack of overhang let water track in quietly.

A short routine saves a fortune:

1. Clear gutters and hoppers twice a year, after leaf fall and again in spring, and check them after any major storm.
2. Follow every downpipe and confirm it discharges into a working drain or soakaway well away from the wall.
3. Check the ground level against the internal floor and any visible plinth. Soil should sit below both, with a gravel apron rather than a raised flower bed.
4. Do not seal the base with a concrete apron or a plastic membrane. Trapping water at the foot of a porous wall concentrates the problem; ventilation does more good.

Inspect after rain rather than before it. Damp patches, salts and algae tell you more on a wet day than a dry one.

Planning pitfalls

Many follies are listed, or fall within the curtilage of a listed building, or stand in a conservation area; some are scheduled monuments. Listing usually covers more than owners expect — gates, boundary walls, garden structures and sometimes the designed landscape around them. Works that affect character can need consent, and that can include repairs, re-roofing, repointing in the wrong material, or taking down an element someone has decided is dangerous.

Start with a conversation, not a skip. Conservation officers are far more helpful when approached before work begins than after. Consent regimes differ for listed buildings, scheduled monuments, conservation areas and ordinary unlisted structures, and the rules vary across the UK, so take advice from a conservation-accredited architect or surveyor before you commit. Wildlife matters too: bats, nesting birds and protected trees can all shape what you may do and when. Do not treat permissions as a formality to be sorted out once the scaffold is up.

Wrong order, wrong trades

Record before you touch anything. Photograph every elevation, measure, note materials, and keep a simple diary of cracks and movement over a season. If something is failing, make it safe and dry first — props, a temporary roof, sheeting on scaffold — before any permanent repair. Then work in the right sequence: roof and rainwater goods, then structure, then surfaces and finishes, with drainage and ground levels sorted before any landscaping. Scaffold towers spread their load on spreader boards, not on soft ground beside a shallow footing.

An excellent general builder can still ruin a folly. Ask what mortar they would use and why, ask to see comparable work, and ask what they would do if

Photo: Nikiko / Pixabay