Planning for runner on flared staircase

I want to have a stair runner on our main staircase. We recently had the stairs updated by having them capped. The shape of the staircase has me asking myself a few questions about how to tackle this issue so I thought I would ask you the same questions.



First the staircase. The first 9 steps (from top down) are straight and essentially the same size (40" wide to the baluster and 9 1/2" deep). The risers are between 5 5/8 and 5 7/8" high. The nose thickness is 1 3/4" and it overhangs the steps about 1 to 1 1/4". The left side of the staircase is up against the wall and the right side is open. Nothing special here.

The interesting part happens on stairs 10-13. This is where the staircase begins to flare. These steps also deviate from the rectangular tread shape and take on a trapezoidal shape. The balusters also start to take on the shape of the staircase so I thought two measurements would be necessary. For example, step 10 is 40 1/2" wide to the first baluster and 41" to the second, but by the time we get to the 13th step, the width increases to 48" to the inside of the newel.

This is where I stop feeling good about my carpet laying skills! If I buy a runner of say 32" width to deal with the top steps, how do I get it to turn into enough carpet to follow the flare? I see examples of carpet being laid on circular stair cases, but all those treads seem to be the same width. Is this an example of where custom made runners are needed? Thanks

 

Not a carpet layer, but you just need to determine what reveal looks good on the edges and mark it out. Then I would be cutting small pieces to cover the riser and tread... staple a piece top and bottom across the back of the riser, then do the tread and wrap the front part around the nosing and staple it underneath. Work from the bottom up.

Figuring your square footage shouldn't be too hard.