Not an uncommon sight: an airbrick that’s been chewed by rodents. On a careful inspection, this one was clearly chewed from the outside and shows a mouse had got into the building. Obviously the problem of them being in the building needs to be addressed but firstly, we need to stop any more getting in.
A rough and ready fix is to fill the hole with stainless steel wire wool. Practical, quick and easy but not very attractive. A better solution in some cases is to use one of these.
A stainless steel mesh fitted into a frame that then attaches over the faulty airbrick. These are much tidier than filling the hole – and yet still quicker to install than cutting out the damaged ‘brick and replacing the whole thing.
This one is a half-brick – the usual size found on most buildings – but full- and double-height versions are also available.