Damp Coursing a 19th Century Stone Wall on a Rubble Base 

Ashridge House is a Grade I neo-gothic country estate, once the royal residence to Henry VIII and Princess Elizabeth I. It is currently used as a wedding venue, conference centre and an International Business School.

As with any property of considerable age, maintenance is to be expected. Freezteq was used to treat a section of wall built in the Early Gothic Revival style in the early 1800s. The external face is a 50 mm thick stone, and the internal face is a single skin of brick. The base of the wall consists of brick, stone, and mortar rubble. 

Considerable quantities of water were rising through this composite wall base and into the 508 mm dressed stone wall above, causing deterioration to the exterior stonework and making the interior environment damp. 

In places, the survey for rising damp revealed that the external and internal skins of the rubble base were retaining water. The structure was acting like a tank and not allowing the ordinary passage of moisture or humidity, trapping a large amount of water within the creviced rubble.

 At Ashridge House, the composite wall bases include a number of stone buttresses. Drill holes were made through the buttresses, using an external application, to within 25 mm of the opposing face. In certain places, this was to a depth of 1110 mm. 

Treatment of this wall type, as well as 13th and 15th century walls at Ashridge House were successfully carried out by the Freezteq damp proof course system. Sticks of Freezteq were found to be the most effective and economical method for treating the creviced walls, as the slow diffusion ensures the large cavities present are not ineffectively filled by solution.