Quite often concrete shells have vertical cracks with huge length. Sometimes there has to be answered the question whether or not could it be possible to apply crack bridging coatings to avoid ingress of aggressive substances deteriorating concrete or reinforcement by substances from operation and environment. It must be known which crack moving characteristic hasto be to carry out determining and dimensioning of a coating. There will be shown exem-plary how the crack movement inside and outside of the shell can be measured on side and which consequences does ithave concerning coating or not.