The 19th century Abbey also serves as a parish church. The Abbey Church is a grade II* Listed building dating from the mid 1800s. The church is noted for the quality of its sculpture and stained glass.

As many old buildings of it age, the Abbey had various dampness problems that required constant attention, rising- or structural damp just being one of them.

The Survey

We undertook a detailed dampness survey of the building complex. This included all administrative buildings, the Lodge, the cloister, the sacristy and the Abbey church – these together cover an approx. 45 x 110 m area totalling about 4,000 m2 ground floor area. The church has over 1m thick walls.

floor plan

Proposed Solution

For the structural dehydration of the walls, in addition to some repair work, we proposed the non-invasive Aquapol building dehydration system and damp proof course (DPC). This system is ideal for listed buildings as it is building-friendly, reversible and non-invasive. It looks like a lampshade, it can be suspended on a ceiling or hidden in a loft.

Its working principle in simple: the system outputs tiny pulses that penetrate the surrounding walls, similar to your average Wi-Fi router. The small pulses decrease the capillary attraction (adhesion forces) between the wall surface and water molecules. Once capillary adhesion decreases, gravity wins. The fine balance of capillarity/gravity is destabilized, the water column under its own weight starts shifting back into the ground and the walls dry out. The system is permanently kept on premises as it will act as a “wireless” damp proof course, not letting the water molecules re-bond to the wall surface, keeping the building permanently free of rising damp. The pulses the system uses are tiny and so harmless to health or any living organism.

Due to the size of the building complex, two large commercial systems were needed to cover the full area. The large size of the building complex requiring more than one dehydration system allowed an interesting scientific experiment: installing one system only and taking comparative readings between areas within and outside the range of the dehydration system. Areas nearby the dehydration system should dry out, while areas outside of its range should stay damp, and this should reflect in the measurements.

Measurement Methodology

Following the installation of one system covering approximately half of the building complex, the Core Conservation technical team has done regular follow-up moisture checks. The dehydration progress has been monitored with the gravimetric method (wall core measurements based on weight). This measurement protocol is described by English Heritage in their practical conservation handbook Practical Building Conservation: Mortars, Renders and Plasters as: Gravimetric analysis of a drilled sample is the most accurate of the analytical methods, and it is therefore used for calibrating other forms of measurements.– English Heritage

After the installation of the Aquapol system in May, regular moisture measurements have been taken at approx. 3-4 month intervals in Sept, February and following May.

Results

The overall dehydration progress is summarized on the charts below:

Dehydration progress chart

One year dehydration progress breakdown

One year dehydration progress summary - Before & after

It can be seen that the moisture content of check points on the left (oratory, cloister, kitchen, mailroom) have steadily decreased from around 10% absolute moisture content to air-dry equilibrium values of 1-2%. On the other hand, check points further away from the dehydration system (church) had a seasonal variation and the results were much less pronounced. Based on the above results, half of the building complex can be considered dry.

The moisture content of the walls within the range of the dehydration system has decreased on average by 68%. All individual measurement points have decreased without exception, some of them significantly. In comparison, areas not covered by the dehydration system have only decreased on average by 2%; some points became drier while other points became damper.

Similar results were experienced in the cellar. According to Brother Peter, the monk in charge of the building, the cellar area within the range of the dehydration system has also dried out considerably, from being “mainly wet” to being “mainly dry” except during heavy periods of rain; after which it dries out quickly.

The Abbey has been very pleased with the results as the dehydration system provides them with a long-term solution for the problem of rising damp, and does it in a non-invasive, building-friendly way.

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