RHS Limited
226-228 Holbrook Lane
A good question, and one that I have been asked several times before.
The usual scenario is that someone converts a house from a two storey to a three storey dwelling, and in the process decides to replace the existing stair. Logically the new first to second floor stair will go over where the existing stair was. So, you end up with two identical holes in the upper floors one above the other above the other. Now you look for suitable staircases to fill the holes.
The problem with using modular kit stairs such as the Kompact or Genius staircase kits is how to support the second floor staircase. The ground to first floor is no problem, it will go where the old one was and sit happily on the floor. However the base plate of the second floor stair needs to sit on, and be fixed to, the floor as well.
This means that it cannot sit in the same place as the lower staircase because its base plate will be sitting on the fresh air of the stairwell. So the second floor staircase cannot be the same shape as the lower stair, it will need to be extended at least one tread onto the landing. This can cause problems with restricting the landing and it can cause problems trying to stretch the same number of treads to reach the intended landing point at the top.
"But I have seen loads of houses with one stair above the other" I hear you cry. That is true but traditional timber stairs are supported in a different way with timber side supports called strings or stringers. These are capable of being fixed and supported off the vertical face of the opening so almost identical stairs can be put one over the other.
It is also true if you have a made-to measure stair with a welded metal under support, these can be manufactured to work in the same way as strings.
Modular kit stair manufacturers have to draw the line somewhere on the number of parts that they make available in their kits, and to my knowledge the only modular kit staircase on the market that has attempted to provide for this particular scenario is the Rintal Stair System. This is a new exciting range that I have as yet only seen in the brochures, so I am not yet sure how well these will work in practice.
One final thought on the subject. Do not forget that most modular kit flight stairs require a floor support pole around mid tread. In most of the systems this can also be taken horizontally to side wall for the upper stair support. It is however worth checking that this will not impinge on the head clearance height of the lower stair.
The Staircase Doctor
12/05/2010 1:04 pm
Yes you can, some of the more up market modular staircase kits, like the Genius RA, or Rintal stair system have quarter landings included in their ranges, most entry level systems do not.
I suspect the question comes from someone who understands the term quarter landing, but perhaps I should first explain the meaning for those less familiar with it.
Staircases can be straight or 'bent', bent stairs can be formed in a few ways.
This term refers to a turn of a quarter of a circle (90 degrees) and is platform put anywhere in an otherwise straight flight of stairs to turn it through 90 degrees. The platform will be basically a square shape with sides the same width as the stair.
As above but now turning 180 degrees so that the staircase forms a U shape. You can put the landings together or have any number of treads between.
As above but now turning 180 degrees so that the stair turns back on itself in a single double sized platform, it can really be any size but typically will be the same width as the stair flight but twice as long. This style is sometimes referred to as dogleg stair, look at the whole stair from the side and you will see why.
The Building regulations call them tapered the construction industry tend to call them call them winders. Some people refer to them as kite winders but this more correctly refers only to the very corner tread which is normally a kite shape, whatever, they are narrower one end than the other. This allows a flight staircase to curve in say a continuous arc or turn say 90 degrees or a 180 degrees by putting a few of them into a straight flight to create the required angle of turn.
There are some specialist variations on the above themes but let us leave those to Grand Designs.
So which of these styles are available in the kit staircase market?
Starting from the top.
Quarter landings as already said are available in the luxury ranges of modular staircase kits on the market. These are more expensive than winding treads but they are more Building Regulation friendly, and they are probably the most comfortable to use. They do however take up more space and they really require an adjacent wall in order to support the platform. You can use vertical floor posts as an alternative means of support but a wall is better if available.
Half landings. Not available in the kit ranges but you can put two quarter landing together (with a step up between them) to achieve the same thing. Obviously half landings are available in made-to-measure systems.
Winding treads. 90 degree and 180 degree turns using 3 and 6 treads respectively are available in most kit ranges on the market. These work well and save space when compared to quarter landings. They do not require wall support, although they invariably need a floor support. To my knowledge there is only one system on the market, The Rintal stair system that allows you to form a continuous curve, this is a lovely luxury range of stairs, but they do require floor supports in order to achieve stability.
As a final word from an old staircase codger, let me say that 90 degree and 180 degree turning staircases can make for really economic use of space in a lot of house styles. In fact a typical dogleg stair will take up less space than the equivalent tread width spiral staircase. “Not a lot of people know that,”
As always never assume that you can automatically use any of these stairs in your project, if in doubt talk to a man who knows.
The Stair Doctor