Sympathetic damp vault options

By: admin | Posted on: May 20, 2020

Have you got a damp cellar in a Listed building where you have exposed stone, and the Conservation Officer would prefer this to be left exposed, rather than having the walls cement tanked, or a plastic membrane system?

The Conservation Officers in Bath, always prefer the Ashlar to be left visible, especially when there has been no previous modern repairs.

There are solutions with sympathetic repairs regarding damp that we can offer; however this will not completely stop water from hydrostatic pressure.

One of the causes where vaults are beneath the pavements is sometimes when cables have been installed, and paving slabs have been lifted, waterproofing below normally gets damaged. Sometimes re-pointing the slabs will make a difference as long as the kerbs don’t keep getting mounted by the delivery drivers, and then driving across the slabs again, causing subsequent cracking. I also find that some of these damp vaults also have continual issues with condensation especially in the winter months. Many also have very limited ventilation or no ventilation.

The damp assessment

First of all its always good to get a capillary moisture reading of some of the mortar to ascertain how wet the walls are. Damp meters can’t be used as these often will read hygroscopic salts, especially in below ground areas. We use gravimetric sampling for this (BRE DIGEST 245), which then gives us a reference point that can always be referred back to if needed. Corroventa desiccant dehumidifiers are also needed when the walls are wet. We can then introduce warm, and dry air. This then ensures the walls are dried down, and the stone can be prepared for lime pointing works. Old worn pointing can be removed, and the walls can be deep re-pointed again with lime. Once this has dried down a suitable lime wash can be applied to the walls. Limecrete floors can be used to replace concrete floors if needed, and even some form of drainage if needed, and even possibly a pumped system. All of this then creates a breathable sympathetic traditional repair, which is in keeping with what the Conservation Officer would expect.

Ideally some form of heat and ventilation can be installed to try and keep any moisture balanced in the future.

If you need some advice, and a quotation for some sympathetic damp repairs to vaults, and basements in Bath using breathable materials, please don’t hesitate to contact us. Complete Preservation are leading experts regarding damp issues in Listed buildings around the Bath areas.