I have been advised that we need a full DPC injected as part of refurbishments to a lower ground floor flat in a terraced Victorian property. I have a few questions:
Although the risk of damage occurring to the adjoining property is slight, injecting a supplementary damp-proof course into a party wall does come within the scope of the Act (section 2(2)(f)).
The injected damp-proof course would have to cover the entire depth of the wall to be effective so it is unlikely to drive dampness from your side of the wall to the adjoining owner’s side.
If the adjoining owner dissents to your notice and surveyors are appointed a schedule of condition covering the adjoining owner’s property will be prepared and then re-checked at the end of the works. Although the party wall file never technically closes, the more time that passes by the more difficult it will be to make a case that any damage is attributable to your works.
Regarding the making good to the gardens walls and whether that would be notifiable – it would depend on the extent of the works. Render repairs would not be notifiable but if any part of the wall has to be rebuilt that would. Pointing (or rather the raking out required in advance) would technically come within the scope of the Act although most owners wouldn’t bother serving notice.