9A Sion Hill, Lansdown, Bath
9A Sion Hill is a Grade II early 19th century terraced dwelling, situated within the Bath Conservation Area and World Heritage Site. The building constitutes a three storey above-ground structure in coursed rubble stone, adjacent to the Grade II listed Sion House. The dwelling was formerly abutted by an easterly wing which adjoined with Sion House, which was subsequently developed to form a separate dwelling at No. 9 in the 1970s.
Whilst BPT does not typically comment on internal alterations without the benefit of a site visit, Bath’s historic vaults and cellars often retain historic features and their original material finish with limited later intervention and their conservation is important.
The existing basement level appears to currently form a basic, ancillary use (see https://www.rightmove.co.uk/house-prices/details/england-101890370-14186248?s=cb57bcfb29811b4f428ad7f1a28b2f9bc39cc2dbbaf2c958d07b05adafbca8e4#/). Given evidence that the ‘Reception Room’ would have originally been in use as the kitchen (note the surviving range in the north-east corner), the principle of a domestic use in this space is accepted.
We recommend further information is provided regarding the proposed stone repair works. Further observation indicates that the existing stonework in the Reception Room is likely pointed in cement and would benefit from repointing works ahead of the application of a plaster.
We further strongly recommend that further details are provided regarding the proposed timber panelling works “in marine grade ply” such as the proposed appearance and finish and over what extent of the walls this would be applied.
We are generally supportive of the proposed works to the vaults and utility to remove existing paintwork, allowing the existing stonework underneath to be revealed. Generally, where possible we encourage stonework in these particularly damp and poorly-ventilated areas to be left uncovered to be allowed to ‘breathe’ as best as possible. Where it is proposed to repaint these areas, we recommend the use of a limewash rather than paint where this is a more materially compatible and reversible addition. Limewash also has the additional benefit of being applied in multiple, thinner coats through which the texture of the historic stonework of the vaults’ interior would remain legible.
We note that as part of proposed works to replaster the Reception Room and Study, it is proposed to use Argical as a pozzolanic additive to speed up the drying process within the “damp conditions” of the basement, although the specific qualities of Argical and why it has been selected are unclear. We therefore suggest that further details are submitted regarding the use of an additive to the mortar and the specific additive choice. There could be an option to consider a lime of a more naturally hydraulic set (purely based on lime/sand/water ratio) without the need for additives.