Do i need to damp proof my internal walls ?

[shreddie102]

I have a victorian school with a slate damp course in the external walls. I am planning on putting in a damp course into the mortar above the slate damp course of these walls.

My question is do i need to put the damp course into the internal walls as well as the external walls , seeing as these internal walls are also sitting the earth below ?

[TheDoctor5]

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[Inform Timber and Damp]

A damp proof course is installed to protect against rising damp, rising damp will therefore affect internal walls - infact will tend to affect internal solid walls more. External walls will tend to be affected by penetrating damp and condensation, therefore i would advise that you have to identify the cause of the damp before spending on a type of action.

[fix]

I have abit of rising damp on an internal wall. It comes about 30cm up from ground level and I guess it's from the cellar.

I'm abit worried about injecting a damp proof course into the wall and the damp going elsewhere under the floor,can anyone tell me if I should be worried or will it be ok?

Thanks