3/4″ vs 1″ oak stair treads and risers and recommended lip width

I’m ripping out the carpent on the stairs in my house and installing oak treads and risers. My staircase has 13 steps and is fairly steep with a 7.5″ rise and 8.5″ tread. I would like to make the treads wider. Is there a standard or code specification for the overlap/ lip of treads? I was hoping to use a 1″ lip to widen the treatds but I don’t want to break code (MD) or have the lip impede the function of the stairs.
Also, pre-planed treads and risers always seem to be sold as butcher block style assembled slabs of 1″ thick red oak. To save money, I was thinking of purchasing solid 4/4 red oak and jointing/planing/routing it myself into 3/4″ thick treads and risers. The underlayment on my stairs is 3/4″ ply. Is there any reason that I should use 1″ thick treads and risers if I’m building them from scratch? Is it a mistake to use solid wood treads due to the risk of warping? Any other wood options I should consider other than red oak?
Thanks,
Lyptus
Replies
lyptus
Unless it's changed in the newer code applications, 3/4 to 1-1/4 is the usual allowed overhang. Using 3/4 treads means more stress on that outside edge. No more than 3/8ths difference between largest and smallest overhang.
Further, by making the treads deeper doesn't do anything to really increase the actual usable stepping width. The run is the same, hence the relationship from each tread to each other remains the same-in your case 8-1/2".
Is your plan adding to the top of your boxed treads with this oak? That potentially is going to throw off the rise at the first step and the last. If by some chance they made allowance for that when figuring for carpet, maybe you luck out. No more than 3/8ths difference again between largest and smallest rise.
There are stair tread caps or covers offered that are thinner and meant to go over previous "unfinished" stair treads/risers-that might be an answer.
Wood species? most anything with of course the harder woods being more practical and the thicker treads more likely to stay sound over time. The last stairs I did were stained poplar.