The world has changed.
From 1227 (the year from which the history of the fireplace is made to begin in Venice) until 1940 (the year in which the Beautiful, the Just, the Healthy, the Humane and the Reasonable ended in favor of the Consumerist, the Industrial, the Ugly and, that's all that was missing, the Chinese) the mode of making a fireplace was only one: The wood-burning hearth. The technicians who specialized in recommending and/or making a hearth, complete with a proportionate chimney and associated chimney pot, were the chimney sweeps. What a beautiful world that was, at least for fireplaces.
Then, in the postwar period, THE DILUTION.
The (obscene) industrial prefabrication, the new modes of combustion and/or "non-combustion" (after all, a kind of fire and smoke can be produced with steam and a little electric shock...);
The magical (so to speak) bioethanol is anything but "bio" but it has been very successful;
And again, a nice gas fire... Or, why not, pellet, in short, you name it....
Obviously, the ancient figure of the chimney sweep, at least as it used to be understood, no longer exists; today this man is called a "stove-repairer," and, in addition to cleaning flues, he has become handy with these modern hearth devils.
This historical gunslinger serves to understand how, since the postwar period, the world of the fireplace, which was completely immobile in the previous 700 years, has in a few decades radically changed, the systems for its operation are many, and, in short, it is not easy for anyone to find his or her way through this chaos.
For our part, we can help you (and will do so gladly as well as in our own interest) :
A) regarding the specific installation of the marble frame (which is basically what we sell) by giving fundamental instructions to your technicians or masons (in case you opt for "Do it yourself").
B) Or (advisable) we can direct you to the best fumigators operating in your area, many of whom we know personally, if only for the almost half a century of work in the same world.