Historic Stourhead gardens grotto closed until September for repairs

The trust says it has closed the Grotto at Stourhead House and Gardens near Mere to replace the floor.  The Grotto was built in 1748 for Henry Hoare II, known as Henry the Magnificent.

Stourhead House and Gardens is Wiltshire’s third most visited National Trust property, with more than 370,000 visitors a year.

A section of pebbled floor lifted in the Grotto at Stourhead © National Trust - Lucy Fenna (Image: ©National Trust Images/Lucy Fenna)

A spokesperson said: “The damage to the Grotto floor was caused by years of water flowing from the plunge pool inside the Grotto into the lake, wearing away the grouting on the brick-lined drainage channel.

“During this, the brick-sided drains underneath the pebbled floor also become blocked and the power of the water has caused a new, unintended, channel to open beneath the floor.”

 The Grotto was fully closed on August 5 to enable these repairs to take place. It will be closed to the public until Monday, September 2.

Visitors in the Grotto at Stourhead. ©National Trust Images - John Millar (Image: ©National Trust Images/John Millar)

Tim Parker, Head Gardener at Stourhead, added: “Although we are currently undertaking essential repairs to the Grotto, investigation work carried out has meant that this work will ensure that the Grotto, which is one of the most popular locations at Stourhead, will be protected and be able to be enjoyed for many years to come.”

In late 2022, part of the floor in the Grade I listed Grotto collapsed greatly limiting access to visitors for safety reasons.  

Since then, investigative archaeological research has been undertaken by specialist teams to understand the sub-structure and drainage of the Grotto building.

An environmentally friendly dye has been used to see how water is flowing from the new channel beneath the floor out into the lake. 

A key section of drain exposed below the pebbled floor in the Grotto at Stourhead © National Trust - Lucy Fenna (Image: ©National Trust Images/Lucy Fenna)

 The pebbled Grotto floor with its concentric circle design, is a notable feature and stonemasons carefully lifted the pebbles to access the under-floor drains.

Once the under-structure was exposed more archaeological recording took place to enable the Stourhead team to make informed decisions about any future repair works that may be needed.  

The trust says a new grout will be prepared and used for the brick-lined channel, meaning it is properly reinforced for years to come.

The pebbles will then be reinstated using a special mortar that will need time to set and fully cure. 

The rest of Stourhead House and Gardens will remain open during the summer.