Cavity in dwarf wall - damp

[Donkey123]

Conservatory is fairly damp, decided to investigate in the dwarf wall cavity. It is hard to see but the bottom of the cavity looks wet and there is definitely damp rising.
should there be a dpm at the bottom of the cavity? Is there a fix if there isn't?
I was going to use cavity closer but that might just be hiding the problem.
Thank you for any advice!

 

[noseall]

Conservatory is fairly damp, decided to investigate in the dwarf wall cavity. It is hard to see but the bottom of the cavity looks wet and there is definitely damp rising.
should there be a dpm at the bottom of the cavity? Is there a fix if there isn't?
I was going to use cavity closer but that might just be hiding the problem.
Thank you for any advice!

It's a connie and won't be built to B'regs standards.

 

[^woody^]

Cavities are not normally closed at the bottom, and building regs don't require them to be.

 

[Donkey123]

Thank you @^woody^ , is there something I could do to stop the damp raising into the cavity?
Thought about Thompson water seal on the inside but it is probably a bad idea, or cavity closer?

 

[^woody^]

No it's normal and not a problem.