RHS Limited
226-228 Holbrook Lane
I assume that you mean a straight staircase with walls either side that are no wider than the width of the stair. The answer is yes you can, this is typically done in a three-bed semi with two main bedrooms and a box room. A staircase is built in one of the bedrooms along the party wall between the two main bedrooms in order to access the loft. Then a new stud wall is built to enclose the stair from the bedrooms. This is combined with forming a new access in the landing wall to access the space saver staircase
This all works very well, and takes up the minimum amount of space, but it does normally mean repositioning one of the existing bedroom doors, as well as building the staircase access door. One thing to be aware of is that open plan metal and wood space saver stair kits like the Karina, Kya, Gamia Mini Plus and Berlin all have gaps between the treads through which you will be able to see the enclosed area beneath the stairs. A good solution to this is to box in the underside of the staircase and put an access door in your new wall to this useful storage area.
An alternative would be to use a traditional all timber closed stringer stair with alternate treads and closed risers. You may find an "off the shelf" traditional timber kit that fits your height and going,or you may have to have one made by a joinery shop.
The Stair Doctor
It is becoming increasingly popular to access roof areas for sun bathing/ party decks etc. This for obvious reasons tends to be a fashion for big city flat dwellers,and who can blame them. Access to the roof normally has to be via a ladder, as typically there is not enough room for a staircase. Continental loft ladder manufacturers have long satisfied this demand, particularly around the shores of the Med where flat roofs are popular. Most of these manufacturers produce a loft ladder that when folded is housed in metal box with an opening lid on top. The whole thing is plonked onto the flat roof and provides a lockable waterproof terrace access. They work very well and solve a difficult problem in one piece of kit, but they are designed for Mediterranean climates. I have only ever seen an Austrian model that was insulated, and therefore more suitable for Northern Climes. I also think that some careful thought has to be given to waterproofing. As all the ones that I have seen are simple galvanised sheet metal boxes that sit on the roof and require roofing felt to be dressed up the sides to finish under the overhanging lid. This is maybe fine around the Med but I am not sure how well it will survive six storeys up facing a gale in an English winter. I am not saying That you should not use these terrace access loft ladders, but I do think you should probably consider carefully the waterproofing details.
So can you have a electrically operated terrace loft ladder? I know of only one manufacturer who does make a model that is offered electrically operated. It would really gain you some brownie points to invite your neighbours onto the terrace via your electric loft ladder. My only real thoughts on the subject are as already mentioned above but more so. You have now added electricity into the equation. Electric circuits do not go well with the sort of condensation that you are likely to get in a tin box on the roof in a British winter. Personally I would make sure to install the supply cable via a trip device, as well as insulating the box somehow. I would also put holes in the plywood lower hatch to allow both ventilation and heat to circulate around the box in winter. The last you want to do is find your expensive 'show off' loft ladder is not working at the first BBQ of the year,the neighbours will not be impressed.
The Staircase Doctor