Many technologies have been used in cultural heritage conservation and documentation in recent years. One of these techniques, laser scanning which is increasingly becoming popular in late years is used for various purposes like surveying, modelling, archiving and visualization in the field of cultural heritage. Plenty of works have been done in heritage documentation with laser scanning technique allowing the user to achieve different information from a 3D model and helping to investigate the shape and components of heritage. This paper deals with how a 3D model can be used to identify the construction technique of heritage and the application of laser scanning for the generation of 3D models of the vaults in Sangallo’s House in Firenze. The aim of this study is to compare the shape and the constructive techniques of surveyed vaults. To achieve this aim, we needed to obtain the thickness and the morphology of the vaults, and this information was provided by laser scanner survey. The paper presents applied technology and instruments used, steps of graphical evaluation and 3D, comparisons between the vaults. In order to make comparison, detailed surface modelling was needed to understand them and to be able to see the differences between construction techniques of the vaults. Leica HDS 6000 laser scanner was used for the generation of 3D model of the vaults. Then point clouds were registered in Cyclone. After that, cross sections were extracted from 3D model to understand vault thickness, shape and to have an idea about how they were built. The results will be displayed and evaluations will be made as conclusion.