Replacing My Basement Stairs
I'm going to do this as a sort of short story/long story thing. So in each section you can decide how much you want to read. If there were lessons learned, I'll put those in two.
Motivation:
Short story: need to replace our stairs in less than 1 month.
Long story: Our dyer had failed and we went out and bought a new one. I knew our basement stairs were pretty dodgy so I figured before either a person and a dolly or two people and a hand crane caried a 100 pound appliance down the stairs I should really evaluate their condition.
Terminology:
Before we go talk about stairs we need a little terminology. The stringer is the saw-toothed piece that supports the treads, and if present risers are mounted to. The tread is the horizonal part you tread on. The riser appropriately is the vertical part that rises between treads. Why the stringer is a stringer, I certainly don't know.
Picture 1:
Evaluation:
Short Story:
These need to be replaced.
Long Story:
They aren't pretty, I'd noticed the top stair was kind of a mess (it's removed in this picture). You can see how it was attached on the right (with a chunk of wood nailed to the top of the stringer).
Picture 2
So, that isn't how a stair is suppose to be constructed, worse yet the stringer is in terrible shape. I know it looks like concrete but what is toward the bottom of the picture is actually the tread, you can tell by the black tread cover.
Picture 3
Stairs are a variation of the simply supported beam, if you want to dig into the engineering for a simply supported beam here you go Simply Supported Beam - an overview | ScienceDirect Topics. However, what is critical is that weight is supported by the stringer pressing into the wall and the floor. Clearly, this stringer isn't in any shape to support the weight. Also it's a 2X10, that isn't the recommended size for a stringer it should be a 2X12. So why is this stringer in terrible shape?
1. It's old, my guess is it could be as old as 30 years
2. It was only painted on one side
3. The unpainted side was placed against cinderblock that leaked. So it was almost always wet.
What is amazing is that these actually could support a person. There are a couple of 2X4 and some other supporting things crammed underneath them. Also, the stair treads got cement around them and the cinderblock which probably provided some support. It's also a credit to building codes almost everything is wrong here and yet they supported me for 15 years. Nobody else used them.
Should I do This?
Short Story: Yes.
Long Story: That wasn't my original intent. However, finding construction help now is crazy so I actually couldn't find anyone to do it by the time we needed it done. We'd bought a dryer at a good price that would be cancelled if we didn't get it installed in a month. Plus, the estimates I got meant several months of trips to the laundromat for drying. I found a great blog where someone replaced and repainted their stairs, now I can't find the link. Plus, the big box stairs seemed to have prebuilt stringers that would work.
Dealing With The Water:
Short Story: Hydraulic Cement and Dryloc.
Long Story. In the picture below the really dark parts near the bottom already have hydraulic cement applied, but due to seepage they stayed dark pretty long. The dark parts higher on the wall are where water is seeping. In the end I applied hydraulic cerement to pretty much all the exposed cinderblock and then followed up with Dryloc.
Lessons Learned: If I'd had more time I think I could have been more judicious about where I used the hydraulic cement. Also if your trying to cement just the leaks a bright light, like the Ryobi work light in the picture is super helpful. Note I'm not sure if you tried to do just the leaks how much the leaks would just move up to the unpatched areas. I suspect if you alternated Dryloc and cement you'd probably be ok. Note in picture 5 you can see the finished work, plus the stringers. There were also some areas I over patched because I didn't understand the problem was water leaking from above.
Picture 4
Day 1 At The Big Box.
Short Story: No the prebuilt stringers are NOT big enough.
Building The Stringers
Short Story: Make sure you know which is your rise and run, have a builders square and stringer building stops.
Long Story: I started by trying to layout various designs for the space. There are three complications I played with. First, there is an odd part near the top where the concrete sticks out. Not sure what it is their for but the wall isn't flat. You can see it as the blue part at the top in picture 2. So should the stringer touch that, should it stop below like the original. Then between the basement and the bulkhead there is a raised entry, you can see that in picture 7. What should the relationship between the last step and the entry way be? The old stairs stopped well before the entry way. Laying this out in sketchup made me more confident that everything would fit. Can't find the actual instructions I used but these guys are pretty good Design and Cut Stair Stringers Using SketchUp and Saw - YouTube. For layout and how to use a tread stop, this is a nice video. How to Layout and Cut a Stair Stringer, How to Build Stairs - YouTube
Lessons Learned: First the top and bottom treads may be special cases. Since you're putting a tread on them that adds ~1.75 inches of height you need to consider this in your design. Second, don't try and build anything to crazy, in the end I ended up with a conventional stringer that landed on the floor and touched the top of the upper part of the wall. Be careful if your stairs aren't 45 degrees that you are doing the rise and run right, if not you'll waste a stringer. Also, I really like using a handsaw to finish it give you much better control. In sketchup it is helpful to know that you want to make components of your pieces and laying out the stairs against your dimensional lumber (your 2X12) will make sure everything fits.
Picture 5
One thing I really like that I did with this project is build two treads, with excess 2X12 that each have 2 2X2 on each side. Put on the stringer it stabilizes everything. That way I could double check the treads for level, check the measurements, and make sure everything fit.
What about the 4X4 and 2X6. This part I'm not wild about, but it seemed a reasonable precaution. Usually the top of the stringer is attached with a stringer bracket. The old cinderblock that the top didn't hold well. Now as I said earlier this is a simply supported beam and as long as the top stringer can't move down you shouldn't need anything to take up vertical load. The bottom of the stringer is attached to a piece of the 2X12 which is mounted to the floor with tapcons, see picture 6. The floor is solid concrete so that is sturdy. However, I wanted some extra insurance that the the stairs weren't going anywhere.
Picture 6
Water Mitigation
I've done several things here. First, I've hydraulic cement and drylocked the space. That has made a big difference. You don't see water pouring in and ending up in the sump, but you still have weepage. The stringers only touch concrete at one point, the very top where there is minimal weepage. They aren't flush with the walls anymore. Also the attachment to the floor is to a different board. If that rots away I can replace the board without having to replace the stringers. Finally, all the lumber is pressure treated and completely painted.
Lesson Learned: Rent the hammer drill if you don't have one. The three holes for the tapcons (each rated at 750lbf of sheer) took an hour with a conventional drill and a tapcon bit. The little cup of water was used to cool the drill parodically.
The Treads
I don't like nails, sure nailed in at an angle they should be good forever but I'd rather use screws. I used standard deck screws with predrilled holes in the treads and in the risers. I used the 2X12 as a template for drilling the holes. This worked pretty well but I forgot to account for the stairs being 2X10s and so on many stairs only 2 of the predrilled holes worked. I noticed that most stairs have a rounded nose, and wasn't sure what that was for. A little web surfing revealed it was to avoid splintering. The right angle edge of an unrounded stair is a classic stress concentrator Stress concentration - Wikipedia. So, off to home depot for a router and some bits. The black treads are also from Home Depot, I was worried that painted stairs would be low friction. Since I didn't finish the wood nicely they weren't but I think they look nice and the cost less than the screws:)
The Final Product
Something about the lighting makes this look better than it actually does. The stairs look sharp, but not home beautiful sharp.
Picture 7
A Delivery Step
So for normal use you just step between the bottom step and the raised entryway. However, if someone was going to bring something in on a dolly I think that would be a pain. I made a custom cover that can bridge the gap
It has aligning features underneath so it won't move. Obviously it is a spare piece from one of the stringers there is no reason any sane person would cut a notch into such a thing. That's actually a scress concentrator again. Fortunately worst case is a 1.5 inch drop.
The real object of the effort, getting the new dryer in. Hmm, perhaps I should paint the dryer stand I do have spare paint, and possibly the wall behind it.
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