Carpentry and Woodworking - Converting tread size on staircase with narrow tread

I am about to install engineered hardwood flooring over a currently carpeted staircase. The existing stair treads are only 9" deep with a 7" rise. I would like to convert these treads to 11" before applying the hardwood.

Has anybody ever done this or have any advise?

My plan is build out each step with 2X4 lumber and 3/4" plywood attached to the riser of each step and supported vertically to the tread below.

I am also debating whether I should cover the existing tread and newly built out portion with a new sheet of plywood to tie it all together. If I do so, the rise will be 3/4" short on the top step, but I am not sure how big of deal that is.

I would apreciate any advice / comment.

Thanks,

I would refer to the local building code, especially before installing one irregular step at the beginning. The first step has a bad reputation for causing falls if it is different from the rest.

It may be better to replace the existing treads with the desired dimension rather than layering on top of the existing ones as it sounds you plan to do. You could install the appropriate hardwood tread in the desired dimensions and skip the engineered flooring.

I must be missing something - I can't see how what you're describing would work in the first place. How can you change the depth of each stair without changing the overall run of the entire staircase? The only way I can see to change the tread depth would be to build a new staircase.

In addition to what mitch and chris have said, how do you plan on installing engineered hardwood on the stairs? Just curious.

Adding structure to the risers will decrease the tread depth of all except the top step. You need to rebuild the stairs including new stringers (if there is additional horizontal space available).