Category: Stairs

Designing and building the first floor stairs, installing cladding and treads, newels, railings, and balusters, plus stair edging

Stair Planning Redux

May 12, 2014 / / 2 Comments

Almost exactly a year ago I spent some time working out where the stairs would go and how exactly they would be configured. This was because the original design work I did had overlooked some issues that the architect caught, but in so doing he caused a lot of other problems. For example, in the approved drawings we have there’s only 5′ 10″ of headroom on the first floor landing. So I recalculated everything last year and had worked out a plan that was pretty good. I used that plan to position and size the basement stair opening.

However, since then I have leveled the first floor subfloor, which means the height from the first floor to the second is slightly different than it was when I made my calculations. Not only that, but if I plan to level the second floor as well I need to consider its height when it’s done rather than its height now.

Stair Planning

Stair planning with minimum required headroom

Another factor is that I read up on load and span limits for the stair stringers. Since the opening for the basement stairs prevents me from having any intermediate support for the first floor stairs, they need to be able to span the whole distance to the first landing, which is nearly ten feet. That means I need to use 1 ¾” x 14″ thick, 1.55E stringers, which are bigger than I planned. That affects the headroom in the landing going down to the basement. Finally, the rise for each step must be equal and no more than 7¾”. The current rise floor-to-floor  averages about 10’11” (131″). I can’t fit more than 17 steps, so the closest rise match is 7 ¾” for a total rise of 131 ¾”. I guess I’ll just level the second floor to that height.

So, I went back to my model in Sketchup and started re-working the plans. I got a bit frustrated because I was spending a lot of time drawing things out just to figure out it wouldn’t work. I finally realized I need to draw the required headroom and clearance, so I could see how much space I needed.

Second floor stairs

Second floor stairs

Once I did that, it started to come together. It’s a tight fit between the multiple stories, roof slope, and other available space restrictions. There are a couple of things that are less than ideal. In the picture above you can see that the second floor landing will need to be notched so there’s enough headroom coming up from the first floor, but structurally it will be fine. There’s also the roof pitch clipping a triangle of headroom above that landing, and the stringers which are notched onto the edge of the landings rather than completely on top to provide enough space to meet code.

The good news is that I can figure this out on the computer and that it will all meet code requirements and I should be able to get a queen-size mattress up the stairs (and not bonk my head on the underside of the landing). Now I can get my LSL stringers on order and start framing the first floor landing.

Basement Stair Opening

May 29, 2013 / / 2 Comments

We’re probably not going to have a finished basement for a long time. When we do finish the basement we’re going to lower the basement floor in order to gain some additional headroom. That will be after we finish the first floor, the second floor, and the outside. In short, we probably won’t have stairs going down into the basement for years. However, we do need to frame out the opening for the eventual stairs in order to finish the first floor. This is just one small piece of the massive 3D jigsaw puzzle we’re working on. Framing the opening for the stairs comes before we put down new subfloor comes before we build a stair landing comes before we build new stairs to the second floor.

Original opening

Original opening

My friend Matt B offered to spend a couple days of his week off down from Milwaukee to work on our house, so I wanted to tackle a two-person project and with the beam mostly done it seemed as good a time as any to start framing the first floor. I finished the stair planning so I knew where we were putting things and I picked up the necessary lumber and some joist hangers. The floor is framed with 2x10s that span the width of the house. Four had been cut at some point to make an access door down to the basement that had then been covered over with hardwood floor. The hole wasn’t properly reinforced and the joists were patched with 2x4s to provide a nailing edge for drywall in the basement.

Floorboards removed

Floorboards removed

We removed the 2x4s and cut back the floorboards where we’d be working. Since the new stairs are further back in the house, the cut joists only partially coincided with the joists that needed to be cut for the new opening. To conserve lumber we did a swap, cutting the joists back to the beam and replacing the cut joists with full pieces and vice-versa. We used mending straps to join together the cut joists at the beam.

Mending straps

Mending straps

At the ends of the opening we doubled up the joists, gluing together the 2x10s and putting in two rows of screws every 12″. We had to remove the top courses of brick to expose the 6×8 wood sill on top of the foundation. The joists were notched into the sill, so we had to enlarge the notches to fit the doubled joists. Once the ends were in place we attached joist hangers and dropped in the doubled up joist along the length of the opening. This was glued and screwed the same way as the ends.

Notched rim board

Notched rim board

At this point we ran into trouble with the joist hangers. The existing 2×10 floor joists are rough-sawn, meaning they are much thicker than the “nominal” 2x10s they make today. Joist hangers are designed to accommodate the 1½” modern 2x10s. It turns out they make joist hangers for rough-sawn 2x10s, but I didn’t know that when I first exchanged the hangers for LVL hangers only to discover they were now too tall, then exchanged them back for the original hangers and bent them into shape with a hammer. Oh well, they’re installed and not going anywhere. The new structure is very solid, though I still need to repair the brick between the joists.

Hangers installed

Hangers installed

In order to get everything straight I used a jack post in the basement to push the joists into position before installing the hangers. I’ll still have a lot of shimming to get the subfloor level thanks to the wonky nature of the joists, but everything here is straight. Thanks to Matt B for all his assistance!

Stair Planning

May 15, 2013 / / 0 Comments

We’ve got two parallel tracks for the next little while: framing the first floor and the mechanical room plumbing. For now I’m working on the framing. My friend Matt B. will be down tomorrow and Friday to help work on the house, so we’ll be tackling the opening for the stairs in the first floor. In order to be ready I had to go back over the stair calculations, re-measure everything and come up with the final plan and position of the stairs. The stairs are extremely complicated because everything has ripple effects and there are some tight constraints.

Stair Planning

Stair planning

For example, the first floor stairs will go straight up to a landing, turn right 90° and go up the remainder. The bottom of that landing needs to be more than 80″ above the floor so that we can put the stairs down to the basement underneath it. The stairs from the second floor to the attic are above the first floor stairs. Those stairs have a landing directly above the first floor stair landing. We need at least 80″ from the top of the first floor landing to the bottom of the second floor landing plus another 80″ from the top of that landing up to the roofline, and there needs to be a consistent rise and run to the stairs to allow them to get to the correct height at the correct place.

To further complicate things, the brick foundation is thicker than the frame walls, so the finished first floor wall will be 9″ from the finished basement wall. In order to have the minimum 36″ stair width going down to the basement, the stairs above them must be wider, which means the landing must be wider and deeper, and the stairs from the landing to the second floor have that much less space to go up the remaining distance because they can’t go through the LVL beam we just put in. Despite all of that, we did have some play in where the stairs could go front-to-back. Moving them back makes the front bedroom on the second floor bigger, but the coat closet, pantry, and walk-in closet in the master suite smaller. We eventually figured it out.

First floor stair opening

First floor stair opening

Despite the stick drawing of the stairs, I did account for the head room under the stairs after stringers and drywall. Everything checks out, but it’s very close to the 6′ 8″ minimum height. I’d really like to have more clearance, not just for tall people but for moving furniture, but unfortunately there’s no good way to fit more in without building a dormer in the attic above the stairwell, something we really don’t want to do.

The stairs from the first floor to the second will be 42″ wide with 11″ treads (including a 1″ bullnose). From the floor to the landing they’ll rise 7 ⅝” per step, and from the landing to the second floor they’ll rise 8″. The stairs to the attic and basement will have an 8″ rise and a 10″ tread. We’ll build the stairs from framing lumber (rimboard for the stringers, OSB for the risers and treads), and eventually cover them with finishing treads and risers that match our floors.