I’d be concerned doing that only because, I believe, in some (all?) jurisdictions, steps of different heights would be a code violation. It’s something a home inspector might pick up on when you sell the house someday.
My thought (and it might not work) would be to drill several small pilot holes at an angle so it goes through both pieces of wood along the crack, fill the crack with wood glue then drive screws through the holes to clamp them together, making sure to counter sink the screws. Then you could fill in the holes with wood filler or Bondo and paint over that.
Like I said, might not work, but it’s a thought.
Or, if have access to the underside of the tread, you could brace it from the bottom with something so it doesn’t flex.
So adding a 1/4 inch piece of plywood should be okay (but you’ll want to set the peice of plywood on the offending stair and measure all the tread heights and make sure that you are still legal. Making sure that the difference between the biggest and smallest is less then 3/8ths of an inch AND the one with the plywood is no more then 8.25 inches. Also, you may want to walk over it a couple of times to make sure it doesn’t feel awkward, and won’t trip someone that isn’t expecting it. That would be my greatest concern. Personally I would really see what I could do about repairing it before adding a 1/4 inch to it.
I’ll second this; people are remarkably sensitive to changes in height for stairs. Think about the amount of time and effort it would take to do a good job on replacing the steps now, vs. tripping and being generally bothered by it for potentially years to come.
Before you cover damaged wood, be REAL sure you have stabilized it - seal it from water, bugs, etc.
This is especially dangerous to do on stairs - you can’t see the rot, termites, etc unitl it breaks when you step on it.
That said - epoxy (full surface contact = seal) expanded metal (aka mesh) on top of ALL of the treads - keep both the texture and riser heights consistant.
First google, I know nothing of the company or their products:
This is just a wild idea - I have no idea if it is even code-compliant
Something you didn’t mention in your OP, do you have access to the underside of the tread. You said it wouldn’t be easy to remove. I’ll take your word on that, but if you can get at the bottom, some strategically placed wood bracing the bottom and some wood glue on top might be just as good.
And that’s precisely why I was looking for different opinions. It’s so obvious, but I didn’t even consider it.
Though I would not be able to remove a tread without destroying lots of stuff around, it would be very easy to go underneath (moving all of the junk aside) and screw on some beefy bracing, complete with a healthy dose of liquid nails. Then the top side can be prepped and painted.
You keep mentioning liquid nails, but in my completely unprofessional opinion, I would recommend wood glue. Get it into the crack as much as you possible can. Even if you can step on the tread to open the crack a bit to really get it in there. Then from underneith screw in some 1x1’s maybe, I would do three or four going from front to back, perpendicular to the crack along the width of the tread. Make sure you make pilot holes and make sure the screwes aren’t too long. Also, I would put wood glue on those as well.
Also, I’m not a carpenter and don’t really know what I’m talking about.
Since you have access underneath, get a quarter sheet or two of 3/4" plywood, cut to size, and screw & glue them to the underside of your treads. The plywood has enough beef on it’s own to be a tread, and this will be nearly an ironclad repair.
I would glue and screw a 3/4 or 1/2 plywood to the bottom of the tread for bracing. Then I would add reinforcement by glueing and screwing a couple pieces of 2x4 to each stringer, underneath the reinforced tread. This helps to guarantee that if, for some reason (say stress cracks from only one piece of the cracked tread being stepped on regularly), the original tread were to fail, the reinforced tread has its own bracing and would hold.
It might be overkill, but it would cost you all of about 2 bucks for a 2x4, and 10 more minutes of your time.
If the steps are just split I would glue and screw from the bottom using gorrilla glue. This keeps the spacing the same. If you think the steps are weak then brace the bottom boards on each side with a block of wood screwed into the sides. You can let the steps float on the braces.
Gorrilla glue is a water activated glue that will foam up and force itself into wood. The screws are really just to clamp the boards in place during this process. Once the glue sets the boards aren’t going anywhere. Think of this glue as wood working super glue. You don’t want it on your hands so wear latex gloves.
I’m not a big fan of painting steps. Sand/stain/finish them to look nice.
I agree with you totally. However, I don’t have much to work with here. The steps were carpeted at one time and had five thousand staples in them, along with lots of big fat screws put in the pine boards they used for the risers (it was a plain open staircase many years ago).
It’s not any serious damage that will harm the safety, but I am not very hopeful about how things will look after I have filled all of the holes and sanded. Paint will hide it all.
I am a carpenter, so can try to give you a few tips.
First, a couple of questions:
1.) Can you determine why they cracked?
2.) It’s the basement stairs and you have access to the underside so why is there no good way to replace them?
3.) Are there risers on the steps?
4.) What type of wood are they? Hardwood?
5.) How old is the wood and is it rotted, etc.?
6.) What are the dimensions?
If you cannot replace the whole step then your best bet is to reinforce from underneath, as suggested.
Plywood has little strength horizontally so while it will hold the step together it will not stop the flexing or sagging. Use a plank of wood equal to or greater thickness to the stair tread and it’s exact length and width.
Cut plank to fit snug underneath stair tread. i.e. you have to hammer it gently in place but it does not distort the existing stair.
Measure and mark where screws will be and drill pilot holes!
Remove plank and apply glue liberally to both surfaces. Carpenter’s wood glue is fine, anything else is expensive, messy, and probably overkill.
Wait until glue becomes tacky and set plank.
If possible clamp or use a jack from the floor to maintain pressure while screwing.
Use flat wood screws with a 1/2" lag and 1/4" shorter than the sum of the stair tread and plank thicknesses.
That should do it.
Upon reading Sparky812’s post I withdraw the suggestion to use gorilla glue. There is no need for lateral support. All the weight is vertical so the glue isn’t critical. I was thinking in terms of reinforcing joists. I would drill pilot holes in the new wood so it pulls it tight to the original wood.
I’m a strictly amateur woodworker so I defer to Sparky as the professional, sound advice. I’d also like to add that a number of folks recommended gluing cracks shut, it’s important to note that with the exception of epoxy, glue is generally not gap-filling. You can certainly glug adhesive into a big gap but it will not provide strength across that gap. That’s why you want your surfaces to be clean and tight fitting against each other and why you clamp the joint together (whether with actual clamps or by using fasteners such as nails or screws). IIRC wood glue requires a gap of less than a few thousandths of an inch.
Since you can get underneath you should also take a look at how the treads/risers are fastened to the staircase sides. If that area is damaged just reinforcing the tread itself might not be all you need to do, since the tread could break free from the sides under somebody’s weight. If you’re gluing 3/4" plywood to the underside of the stairs you can add some little cleats (support blocks at the ends, fastened to the sides with glue & screws) to provide support for the bottom of the treads.