I'm thinking through on stair treads and risers project and was wondering if an EXPANSION GAP is necessary. It's been driven into me that hardwood floors will expand/contract (as any other solid wood materials) but from all I've seen regarding STAIRS, they're all flushed: treads are butted flushed side-to-side with walls (or skirt boards) and risers are flushed from bottom-to-top of each tread.

Should I play it safe and add 1/8 expansion gap to the treads and risers? I can hide the gap on the risers with a stair skirt but not sure about the riser.

I live in Nevada and the high dessert climate has minimal moisture. Please see attached pic of my stairs that I've prepped for treads/risers. I intend to use 1x... solid wood plank (stained) for each tread. Risers material can be anything thin and minimal expansion (MDF?).

Thanks for any help.

 

The skirts should go in before the treads and risers.
The was no need for any of that wood you have installed. The risers and treads get attached directly to the stringers.
No gaps needed.

 

Joe, this is a remodel. The existing stairs was covered with carpet which I removed. I'm going to install new treads and risers over existing rough wood.

 

Got ya, still a lot easier to remove that plywood, install the skirt and install the treads tight to the skirt. That way there's no visible gaps.
If you really meant using solid wood for treads it's going to be hard to keep them cupping an splitting.
Treads are almost always laminate with strips of real wood not all one piece.
If your going to leave that plywood place conceder using over treads like this so there's the needed over hang and it covers the tops of the risers.
http://www.stairpartpros.com/Retro-F...no-Return.html

 

Thanks Joe. I didn't realize that it was easier to get rid of the existing plywood and install fresh to the stringers. I'll keep that as an option. I'll also look into the other materials you mentioned for the treads. I'm a DIYer so I'm glad to have advice from veterans here.

 

The more you can prefinish before installation the easier it will be on you! I'd stain [or not] and apply 2 coats of poly [sanding between coats] to all the wood [primer and enamel if the risers/skirt paint] That way when you install it, you only have to putty, sand, dust and apply the final coat. Besides being quicker/easier, that only ties up the stairwell for one drying/cure time.

 

If you tried to cut skirts like you suggested after the treads where installed you will have to have them perfectly cut so you do not end up with gaps under the skirts.
If the skirts are in place already and there's some small gaps there going to be covered up by the treads and risers.
If the stringers where installed correctly there would be a 2 X 4 holding the stringer off the wall studs so there would be no be no needed for stepped cuts.
Just cutting the treads is going to be a challenge. There not all going to be the same length and some may even be at a slight angle. That's why I have a stair gauge that acts as a template.
I also have a 12" compound sliding miter saw so I can make the cut in one pass. A nonslider is not going to be able to do that.

 

Mark,

Agreed on the pre-finish installation. From all that I've read and seen (on YouTube), it's preferable to prefinish and stained/paint prior to installing the new treads and risers on top of exsiting plywood stairs.

The only thing I haven't nailed down (no pun intended) is expansion gap for stair treads. I've read a couple of references that hardwood tend to expand/contract on the width and NOT on the ends. Maybe that's why I see a lot of treads butted up against the side walls on all the installations pics?

 

Joe,

My plan is to keep the plywood stairs as is and retrofit treads and risers on top of the existing plywood. I've already considered riser height and everything will be in spec as before.

After I've installed the new treads, I will cut scribe and cut new stair skirt boards and install on top of the treads. This site has excellent instructions on how to do it:

Scribing Stair Skirt Boards Revisited | THISisCarpentry

I guess using this method, I wouldn't have to worry if the treads will expand/contract since it will be hidden under the stair skirts.


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joecaption1
If you tried to cut skirts like you suggested after the treads where installed you will have to have them perfectly cut so you do not end up with gaps under the skirts.

If the skirts are in place already and there's some small gaps there going to be covered up by the treads and risers.

If the stringers where installed correctly there would be a 2 X 4 holding the stringer off the wall studs so there would be no be no needed for stepped cuts.
Just cutting the treads is going to be a challenge. There not all going to be the same length and some may even be at a slight angle. That's why I have a stair gauge that acts as a template.
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