Building a New Basement Stair


Newly completed stairs, view from old doorway.

We had initially planned on only painting the den and changing the carpet but the carpet place had a big sale on what we wanted and a special promotion for free installation so we got a quote. The price seemed good and we decided to have the stairs recarpeted at the same time since it was almost as bad as the den. The installer’s rep came out to inspect and do a final measure, he turned out to be a really good guy and gave me a number of useful tips from his years of being an installer when he was younger. One tip was for me to remove all the old carpet and padding and have the floor ready when the guys got there. He said that they charge extra for the time to do this and also charge a disposal fee for what they take away and if I found anything that needed to be fixed I could reschedule the install until after the work was done but if the guys came out and found anything that would stop the job I would be charged for the time they wasted.

The den is on a concrete floor so removing the carpet was as easy as cutting it and rolling up the pieces. My garbage took the carpet so the total cost for this was zero. Next I started to remove the carpet from the stairs. Under the carpet the first thread had a huge crack in it, then the second and now the third was found broken. At this point I stopped and had a good look at the rest of the stairs.


Old landing, repaired once.

The stringer was sitting on the landing with no support and at the top of the stringer was two huge cracks so the stringer was no good either. I had remade that landing when we moved in as it rocked and flexed when you walked on it. The person who built it used 2x4s and two pieces of plywood for the top but did not add a support where the two pieces joined, that made the flex and the rocking was caused by the nails pulling out and twisting. You can see my quick fix uses 4x4s and carriage bolts.


Ruthie loves to be in the picture

You can see the two cracks here, the photo makes them look better than they are but every time I walked these stairs I could feel the stairs moving and making noise as these cracks opened and closed.

Starting the new stairs: The web and youtube were very helpful in planning the new stairs. One of the first things I found was recomendations to consult the local building codes. I did this and found that the old stairs had too high a rise and the stringer were made with wood that was too small. In my area the homeowner is allowed to make “home improvements” that don’t comply with local code but since I had to buy all new material to build this stairs I used the code as my baseline and in most cases I went above the minimum requirements.

During planning I asked my wife if she wanted anything changed on the new stairs and she complained that she was afraid she would hit her as the bottom landing was too near the ceiling. I hadn’t noticed this but she was right and the space was also smaller that the requirement in the code. To change this I would need to shorten the top landing and move the stairs further away from the ceiling. This move would require that the door to the garage be moved to the den. That’s now a big deal so I slept on it for a few nights.

All the homes in my neighborhood were made by the same developers and quite a few of them are very similar in design to our home so I have a keen interest in them and always try to see what they have done and it was noticed that all of them had the garage door going into the den and not the stairs like mine. I never liked that door and how it blocked the stairs and what a pain it was to bring anything in especially groceries which you do often.

Back to the hardware store and a chat with the boys at the door department. They said I need a firedoor and spend a few minutes showing me how it should be mounted. At home I find that it’s not a firedoor and it was the wrong frame for the opening and it was mounted wrong and that wrong mounting caused the door frame to crack all around the door. So not only is it a tiny door in the wrong place but it’s the wrong door and they broke it installing it! Great.

New firedoor costs $190 and takes two weeks, I’ve ordered the carpet but they don’t schedule the install until it arrives so I can put them off until all the work is done. I order the door and start the stairs. Youtube videos show many ways to make a staircase, I have to pick on that I feel I can build with the tools I have. One guy says you can make the whole thing with just a handsaw and a chisel and I’m sure he’s right I’m just not that guy and keep looking.


This is the first cut I made, it allows the mockup to sit flat on the floor like the finished product will.


Here I’ve made a mockup of the stringer angle from the height and length needed in the basement, this way I can make sure everything is correct before cutting anything.


You start by clamping a piece of wood on a square that has been set up to show your thread length and your rise. You then transfer those dimension to your stringer in pencil to make sure everything lines up. I did this many times making adjustments each time, a good tip I found was to use a different colored pencil for each try.


This full size drawing on graph paper allowed me to easily transfer the marks on my stringer to the template boards.


To build the stairs I chose a method that uses a router and four templates, one for the thread and one for the riser on both sides. You can do it with just two but it is easier to accurately cut two squares than to get an “L” shape perfect so I went with that.


Above is one thread template, you can see how I notched out the end to get the contour of the bullnose on the thread. The piece of wood under the template is one of the guides to keep the template on the same angle for all the treads. On the right is the riser template, you can see that I’ve been cutting here, you just line up each template and cut out the slots and repeat for the entire length. It took me about a day to cut each stringer.


Here you can see how once I get the markings perfect on one stringer I transfer them to the other. This requires that you move the reference on your square to the other side (in background).


I don’t have any shots of assembling the staircase or of the hardwood wedges I had to cut to shore up everything nice and tight but suffice it to say it was the hardest part of the job. The wedges were cut from an oak shelf bought for this purpose, you have to cut them with a slight variation as each one needed to be slightly different. My building code says you need to use long and large nails to hold the threads as they won’t break off like screws will but there is an allowance to use a screw to aid in assembly which is what I did. I also used glue and construction adhesive. As an extra and likely overkill point I doubled up on the riser boards with one blind riser and a custom one cut for each step that is attached to the front.


The tops of the stringers were cut off after a test fit since I wanted a perfect fit here.


The bottom thread is open because the last staircase was too and the cat liked to play in there so we grandfathered it in. The stringer sits on a very large plank and is attached with carriage bolts, if this plank were to become damaged from moisture it can be replaced without removing the stairs. The landing is also easily removable because there is a floor drain underneath, it’s heavy but you can move it.

It’s been installed about four months now and we’re still very happy with the results. The new door is in and all the drywall has been repaired and painted. We love the carpet too. Next I’ll put up a hand rail and it will be finished. We’ve saved a ton of money thanks to having some basic tools and using youtube and our local hardware store.

For my next post I’ll be documenting the installation of a pretty large assortment of LED lighting and dimmers.





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