This site has one contact form and nothing else. No account system, no newsletter, no advertising network. This page says exactly what is collected.

The contact form asks for what you choose to put in it. Whatever you send is stored on this website and emailed to a monitored inbox so it can be answered. It is not sold, rented or passed to any third party.
Like any web server, this one records ordinary request information: the pages requested, the time, the browser user agent and the network address the request came from. That is used to keep the site working and to see which pages are read.
Every calculator on this site runs entirely in your browser. The sizes, materials and jurisdictions you select are never sent anywhere, are not stored between visits, and are not visible to this site or to anyone else.
WordPress and the hosting platform may set functional cookies needed to serve the pages and to protect the form against automated submissions. There is no advertising or cross-site tracking cookie on this site.
Web fonts are loaded from Google Fonts, which means your browser makes a request to Google to fetch them. Photographs are served from this site rather than from a third party.
Form entries are kept so the question can be answered and so a later message makes sense in context. If you want what you sent deleted, say so through the form and it will be removed.
If this policy changes, the revised version replaces this one on this page.