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Opinion
Sproughton Mill, Sproughton, Suffolk.
On Monday 1st November 1999, I met with Mr Robert Jones in respect of the above property, which has a Grade II Listing.
- The brickwork should only have been taken down after meticulous recording on drawings and on vertical and lateral gauge rods. This is normal to ensure that as the work comes down, course by course, the bricks are numbered and positions noted for their organised re-use, thus ensuring the bricks are re-laid to their original postion and to ensure that bricks from internal leaves do not end up on the face; where they may rapidly deteriorate.
- The designated cement-based mortar mix, would rarely, if ever have a place on the repair or restoration of traditionally constructed brick buildings. This mix was in favour with the heritage bodies up until recent times, but no longer. Impermeable cement-based mortars are primarily designed for modern masonry brick construction, which is thin walled and highly stressed. The mortar acts as a glue and the brickwork behaves with a “raincoat” effect, shedding rain water down the face of the wall. Traditional thick-walled brickwork set in softer, flexible lime mortar, acts as a gasket between the bricks; the brickwork having an “overcoat” effect whereby the wall soaks in rainwater but then dries-out in subsequent dry spells. In essence, the open-pored structure of the lime-based mortar joint serves as a conduit through which the wall breathes.
- The introduction of a cement-based mortar into the large area of rebuilt brickwork will have the effect of putting the overall brickwork of the building out of equilibrium in terms of its structural and thermal dynamics. It also presents future problems for affecting any necessary repairs to the brickwork. Should any of this brickwork ever need to be taken down, then salvage of the original bricks for re-use will be extremely difficult; if not impossible. The replacement mortar, therefore, should have been based on an appropriate class of hydraulic lime, carefully designated, to achieve the strength characteristics being sought.
- The reconstruction of the brickwork has created aesthetic problems with the selected new level, which it was deemed necessary to follow to resolve the structural concerns of the original brickwork. This has unfortunately adversely affected the overall character and charm of this building due to the following:
1. The windows levels on the rebuild sections are now seriously out of the all important alignment with the remaining original work.
2. The size of the top floor “blind” window has been substantially affected because it was necessary to squeeze it into the remaining space below the roof eaves.
3. The standard of bricklaying, when viewed from a distance appears to be satisfactory, but is less so under closer inspection and does not truly match the surrounding existing original brickwork. This can be seen as:
Conclusion
Due to the listed status of the building, however, once the masonry was braced and supported (to the satifaction of a structural engineer) I would have expected a sensible period of consultation with all interested parties and relevant heritage bodies to have been combined with careful planning of proposed works to rectify the problems. This would have helped to ensure that the repairs to the brickwork would have constituted an acceptable level of minimum interferance with the original fabric, to prevent the charm of this handsome building from being significantly altered. Also to help ensure that the materials and techniques specified were, as far as possible, in keeping with the traditional constructional and aesthetic characteristics of the building.
I am of the opinion that such works to an important listed building would not have been either allowed or passed as satisfactory, had they been executed by the client. There are several reasons for this conclusion.
It was suprising to read that in a Letter Dated 27th August 1997, English Heritage deem that this new work has been carried out in an acceptable manner.
To conclude, it is indeed unfortunate that circumstances appear to have pushed the deemed necessity of the executed works ahead of these normal considerations. This has resulted in the new brickwork, constructed in a cement-based mortar, being significantly out of character and equilibrium with the original brickwork constucted in a traditional lime-based mortar, combined with the undoubted negative aesthetic considerations as detailed above; which is not a satisfactory outcome for the repair of this important listed building.
Gerard C J Lynch
Historic Brickwork Consultant 3 November 1999
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