What do you mean by coating strength?  Do you mean the ability of a chemical composition to shield the electromagnetic fields?  If yes the answer is yes.

There are some electromagnetic field shielding paints currently available in the market just Google (Electromagnetic Field Shielding Paints).

Electromagnetic radiation is a energy and it can't be easily shielded with coating however copper paint coated on a conductive container and should be earthed properly is useful. copper shelf or room  as a whole should be layered with copper sheet on the inner wall and of the  floor with proper earthing is the best solution and fail safe.This method is used in broad casting Industry.If you tell specific requirement  enable me to give right solution

Electromagnetic field can be shielded using some thin conducting layer. The electric field is reflected back  from the conducting coating. To absorb the radiation some resistive material should be combined with a pyramidal geometry, that is the way the absorbing pads are designed, the absorbing pads are used to cover the walls in the anechoic chamber.

There are conductive rubbers available which can provide very good shielding. It could be neoprene or such other material. This works based on reflective principle. 

There are certain carbon coated material, which are RF absorbents.

Dear Sir,

yes it is possible with a absorption coating ( a layer or thick film or paint layer ....

with a rf resistance ´´ (f), µ´´(f) or eps´´(f) material loss to  reduce the electromagnetic field .

Or the second way is, to use the reflection effect with a very low resistance material like

metal , or metal hybrid materia ...

Sincerely yours

F. Gräbner