A thick concrete wall can keep your house cool. Steel will make your house hot unless you insulated the walls well. Insulated walls don't work very well in a flood zone. When they get wet, you need to tear them apart. You will need concrete for the foundation most likely unless you are driving steel pylons. There is probably a combination of the two that will suit your needs best. It would be helpful to know what you want to achieve by using steel. There are advantages to both. Steel floors can be cantilevered further. It is easier to make bigger window openings. Floor and roof spans can be lighter and quicker to build with steel, but the roof will get hotter and therefore need good insulation and need to be well ventilated. These are just general assumptions of certain building practices so that you know what to ask people where you live. The practices and resources vary from place to place and building something for a specific purpose can change the benefits of one material or the other. My best guess is that you will probably want to use both.

The metal stairs have metal cross members. Drill holes in them so you can bolt wood to them. This will you give you a nailing surface for the treads.

Hello there, When you have considered granites as window frames, it will definitely outperform than any other material as it is a natural stone. Second, the borders and frames need to be put up very carefully with a skilled stone worker only and please ensure the appropriate mortar mix before fixing. Third, mirror polish is needed for the frames as they look incredible when using with uPVC profiles. Fouth, pre-drill holes for hinges and security grills. Hope your project turns out good. Regards, Aurum Ideas and Spaces Bhubaneswar

That explains his opinion. Your description until now was for outlay doors. Slideline 16 is capable for 50-60 kg and 18-24 mm doors only. As I said earlier, not a big fan of bottom running sliding systems. Hope it works fine for you. Steel decorative strip is possible . But avoid deep cuts on the door that would increase the chances of bend/warp.