Topright banners

Ecclesiastical & Heritage World Scanaudio

Current Issue

Ecclesiastical & Heritage World Current Issue

Ecclesiastical & Heritage World Lighting Dynamics UK

Ecclesiastical & Heritage World JTC Roofing Contractors Ltd

Ecclesiastical & Heritage World Nimrod

Back Issues

Ecclesiastical & Heritage World Back Issues

The non-invasive system that’s at the Core of damp treatment Print E-mail

Belmont Abbey, just outside Hereford, is a Roman Catholic Benedictine monastery which also serves as a parish church for the local community. The abbey church is a Grade Two*-listed building dating from 1860. It was designed by Edward Welby Pugin, son of the celebrated architect Augustus Welby Pugin, and is noted for the quality of its sculpture and stained glass.

As with many buildings of it age, the abbey had various dampness problems that required constant attention – rising, or structural, damp being just one of them. Specialist damp treatment company Core Conservation were engaged to survey the building and proposed the Aquapol non-invasive system.

The company’s experts undertook a detailed dampness survey of the building complex. That included all the administrative buildings, the lodge, the cloister, the sacristy and the abbey church – together covering an area of approximately 45m by 110m, about 4,000m2 in total. The church has walls over one metre thick.

Proposed solution

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

Its working principle is simple: the system outputs tiny pulses that penetrate the surrounding walls, similar to a wi-fi router. The small pulses decrease the capillary attraction – the adhesion forces – between the wall surface and water molecules. Once capillary adhesion decreases, gravity wins. The fine balance of capillarity/gravity is destabilised, the water column starts shifting back into the ground under its own weight and the walls dry out.

The system is permanently kept on the premises as it will act as a ‘wireless’ damp-proof course, preventing the water molecules from re-bonding to the wall surface and 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 at Belmont Abbey, two large commercial systems were needed to cover the full area. The fact that more than one dehydration system was required allowed for an interesting scientific experiment. Core Conservation installed one Aquapol system only and took comparative readings between areas within and outside its range. Areas near to the dehydration system should dry out, while areas outside of its range should stay damp; and that 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 performed regular follow-up moisture checks. The dehydration progress has been monitored with the gravimetric method – wall core measurements based on weight.

That particular measurement protocol is described by Historic England in its handbook Practical Building Conservation: Mortars, Renders and Plasters thus: “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.”

After the installation of the Aquapol system in May last year, regular moisture measurements have been taken at approximately 3-4 month intervals – in September, February and the following May. The overall dehydration progress is summarised in the chart (above).

It can be seen that the moisture content of the check points shown 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 (in the church) had a seasonal variation and the results were much less pronounced. Based on those 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 Aquapol system have only decreased on average by 2%, with some points becoming drier while other points became damper.

Dampness measurements (left) and the device being installed

Similar results were experienced in the cellar. According to Brother Peter, the monk in charge of the building, the cellar area near to the Aquapol system has also dried out considerably – from being ‘mainly wet’ to ‘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 Aquapol system provides them with a long-term solution for the problem of rising damp – and does it in a non-invasive, building-friendly way.

For further information visit the Core Conservation website at www.coreconservation.co.uk or call 0131 661 9068 / 0750 746 8303.

 
Privacy

Copyright © 2018 Ecclesiastical and Heritage World. All Rights Reserved. Designed by DMM Hosting Ltd.