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.

hi Prinka, I would like to note down some problems you are having for this space and further ill give you solutions to make it better. I highly recommend to hire a designer to make these changes for you. 1. wall around the staircase 2. Railing change or refurbishment (think about how much you can spend) 3. Steps refurbishment (treads) 4. Lighting (most important) 5. false ceiling (area false ceiling) solutions 1. wall around the staircase Brighten up the space my luster or hi sheen paint or do a texture paint or put a wall paper. make sure do damp proof course to avoid any seepage of water. 2. Railing change or refurbishment (think about how much you can spend) changes the verticals (railing balusters) of railing to something simpler modern or designer as per your liking. or do a color change. find couple of examples of before and after railing pictures. You can even do a glass railing notice the color and contract added to railings and steps 3. Steps refurbishment (treads) i can see wooden stairs -do new polishing or change it to veneer or slab of solid wood -Burma teak /walnut. add details to it. refer picture below. 4. Lighting (most important) lighting it the most important here, as the space is dark and dull, you need to have surface lights, false ceiling lights above the landing area. picture lights to enhance your family pictures. 5. false ceiling (area false ceiling) do some false ceiling if height permits. simple will do, as less is always more. For doing all this, I highly recommend to hire a designer to make these changes on these points for you, the designer will take care of all the vendors needed for construction part to light changes, repair works & sourcing of materials. Sit back & relax, give 15 days of time to have a nice looking staircase & enjoy the space. cheers.

vedikaseth Bombay rains are harsh! The one thing you can do is use flexible covers that work similar to roller blinds, and are transparent which allows the light to enter. There are many companies that offer such a product. Just choose one where the installation is easy and taking down the sheets is not an issue once the rains are over. Do keep in mind however that the water will still enter the balcony, you will simply be reducing the force of rains, and will require a water outlet.

sararahim123 What constitutes an adequate illumination level varies from person to person. What exactly do you require illuminated? If its simply ambient light you would have tiny lights as shown that throw light on the stairs itself. If a bit more is required you could consider adding a railing with a light under. If general illumination is what you are going after, but in a muted way, would suggest wall scones that throw light upwards onto the ceiling, diffusing the light.