Fitting a new staircase into an existing opening
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
One of the most common questions we get is the simplest: can I just put a new staircase in the same space as the old one? Usually yes, but it helps to know what the space will let you change and what it will not, because the opening you already have decides more than most people expect.
The opening usually sets the rules
Two things are effectively fixed unless you rebuild: the floor-to-floor height, which sets how much you have to climb, and the size and shape of the stairwell, which sets how much room the stair has to do it in. Between them they largely decide the number of steps, the rise and going, and the footprint. That is why a straight replacement often comes out very close to the old stair in geometry, even when it looks completely different. How those measurements are actually taken, and why a survey beats a guessed figure, is on the how a staircase is measured page.
What you can change without moving the opening
Plenty, and this is the good news. Within the same opening you can usually change the whole character of the stair: a different timber, painted or stained, open or closed strings, timber spindles or glass or metal, a new handrail, feature bottom steps, the lot. The structure fits the same hole; the look is yours. So if the old stair is tired or dated but the space works, you are mostly choosing a new stair, not a new opening. What a good replacement fit actually looks like on the day is covered on the installation page.
What turns it into a bigger job
Three things push it beyond a straight swap. Wanting to change the geometry, a shallower pitch, a different turn, more headroom, means changing the rise, going or the opening, and that is where building control can come in and where the space has to give somewhere. Widening or moving the opening is building work in its own right. And a stair that never really worked, too steep or too tight, cannot usually be made gentler in the same footprint, because the maths does not allow it. Whether a replacement needs building regulations sign-off is its own question, and worth settling early rather than late.
Turns and awkward spaces
Where the opening is tight, the answer is often in the turn. Changing where the stair turns, or swapping a straight flight for one with winders or a landing, can make a new stair fit an opening that looks impossible, or make a cramped one feel better, without enlarging the hole. That is a design conversation best had on a survey, looking at the real well and the room around it rather than a plan.
Frequently asked
Can I fit a new staircase in the same space as the old one?+
Usually yes. The existing opening and the floor-to-floor height largely fix the geometry, so a like-for-like replacement tends to keep the same rise, going and footprint. What you are really free to change is the look: the timber, the finish, the strings, the spindles or glass, and the handrail. The structure fits the same hole while the character is completely up to you.
Can I change the shape of my stairs when I replace them?+
Within limits. You can change the look freely, and you can sometimes improve how a tight stair fits by changing where it turns or adding winders or a landing. But changing the actual geometry, a shallower pitch or more headroom, means changing the rise, going or the opening itself, which is a bigger job and can involve building control, because the space has to give somewhere.
Will a new staircase need building regulations?+
It can, and it is worth settling early. A like-for-like replacement in the same opening is a different case from one where you change the geometry, the width or the opening, which is more likely to need building control involvement. Because it depends on exactly what changes, the safest approach is to establish it at the survey stage rather than after the work is planned.
Ready when you are.
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