We are busy with a study build and looking at the possibility of a spiral staircase instead of a closed off ballustrade

Require staircase on existing building, double story. Staircase must be enclosed with roof, walls and include light fitting

We want to do this on a budget, so we want to use the existing wooden stairs and have a balustrade inserted as well as railings on both sides and the wooden stairs filled in. My husband wants the steps to be carpeted, but we are still discussing it. I would like glass or Perspex, and he might be thinking steel or something similar, but it needs to be safe and childproof, in other words, a 4 and 7 year old boy shouldn't be able to fit their head through the balustrade. Thanks.

The staircase is 3.8m. Doesn't have to be wood, can be metal. Just want to get an idea of price.

The rail will only be on one side as the other side is a high wall.. I prefer a combination of glass and metal.

14 wooden steps in total in an L-shape where the landing is. Each step should be approximately 75cm by 25cm with 12cm height inbetween. First 4 steps then The landing (should be approximately 75cm by 90cm) then the other 10 stairs

2.6m length and 900mm width Need it the sanded down and painted white with glass rails