How to Widen a Staircase?

[Alison M.]

Hi all, I looked at a rehab candidate yesterday, an old rowhouse in NE DC. I like the property and will make an offer but I am stumped about how to estimate widening the staircase to the basement. First to clarify: by "wide," I mean the distance hip to hip as you start to go down the stairs, not the depth of each stair tread. This staircase was the narrowest I've ever seen - I am roughly 20" across at the hips and I was having trouble wedging myself down the stairs.

Any idea what is involved in widening a staircase like that? It hugged the party wall of the rowhouse on the right, and opened onto the basement on the left, as I went down.

Thanks! Alison

[Walt Payne]

@Alison M. There are multiple factors involved.

One is that the opening through the floor will need to be enlarged. This is easy enough for someone who knows how, but is not a task to be undertaken by the inexperienced because it involves structural integrity. Joists have to be properly supported and headers properly installed. You will need permits, and this type of project would likely need a structural engineer or architect to do the drawings.

Another consideration is where the extra space is coming from. Would widening those stairs make a hallway too narrow? Would it effect a load bearing wall? Would it involve ducting, plumbing or electric running through the walls?