Bostik Aquaproofe - garage wall

[RH83]

Hi

I have a single skin brick detached garage (new build House)that I am having a bit of trouble with water ingress.

I am just wanting the garage to be used for storage of ‘normal garage’ items, tools, lawnmower, bikes, scooters etc.

I have already applied a seal to the outside but still some water ingress / damp through onto an old wooden bookcase.

I am thinking of using Bostik Aquaproofe on the internal walls and then put some plasterboard on the walls. From looking around I am planning on doing:

Apply Aquaproofe
Attach batons to wall (with a DPM between wall and batons)
Attach Plasterboard to batons
Build my own shelving units

Any thoughts / advice would be greatly appreciated.

Many thanks in advance.