Understanding Stair Drawings in Floor Plans: Stacked Stairs and Switchback Stair Tower Explained

Stairs are tricky to read in a floor plan, especially when we have stacked stairs, or multiple stairs on top of each other. We will quickly look at four stair drawings in this example. We have a stacked stair, and this stair has a landing in the middle.

We also have three different levels of a switchback stair. We could also call this a stair tower. We have the top floor, a middle floor, and the ground floor.

Let's look at the first stair. Where you see text, either up or down, this is where you can picture yourself standing. If you follow the arrow, you are either walking up the stair treads, or standing here and walking down the stair treads.

So on this floor plan, we have an up and a down, and these two points are on the same level. If I'm standing on this up text, I can walk up the stairs here. And if I were to stay on the same level and go around to the down text, I could go down the stairs here.

When stairs go up, they will end in a break line. This break line represents the section cut of the floor plan. In this case, we have a double break line.

The first break line represents the section cut for these stairs that go up. The second break line tells us that these stairs are running down. These stairs continue down below the stairs above.

Let's take a look at this in 3D. Remember, these two people are standing at the same level. This is why we saw up and down on the floor plan.

We can see the stairs going up from the left and down from the right. Now we can see where we placed our break line. It replaces this section cut shown here in our 3D view.

---

We can see the stairs running up from the left, and the stairs going down from the right continue below. So in this case, we represent this condition with a double break line. Now let's look at the top floor of a switchback stair.

This would represent a stair tower. Again, when I see down, I know that I am standing on this level, and the stairs go down, turn the corner at the landing, and go down again. Notice that there are no break lines because there are no stairs that are being covered by other stairs, and no stairs that are cut by our section cut of the floor plan.

This person is standing where we saw our down text. We can see that we go down the stairs to the landing, down the stairs again, and are on the landing on the floor below. We can see that the landing on the floor below is covered by the landing at the top floor.

This becomes more difficult to understand when we are on a middle floor, when we have some stairs going up and some stairs going down. We see here that we have a down arrow, just like our top floor, and an up arrow so we know that we are standing on this level and have stairs going up and down from the same landing. In this case, the stairs going up are ending in a break line, which we know means that they are cut in section.

And the stairs going down end in a break line because they are covered by these stairs above. So, like in our straight-run stairs, we have a double break line. We are only showing one person here, but this person could go up the stairs here or down the stairs here.

You can see where it is cut. This will be the break line for the stairs going up. You can also see the steps going down, and here they go below the stairs above.

So again, we would have our break lines here because these stairs are going up, and here the stairs are going down around the landing and continuing down. So in our plan view, the stairs are running down underneath the stairs running up. And then, at the bottom of our stair tower, we only have stairs going up.

---

However, we know that this stair will turn at the landing and continue up. We know that by looking at other floor plans for this stair tower. So how can we have a storage space underneath it? The key to remember about floor plans is it is not always a full height space.

In this case, the storage room is a partial height space underneath the stairs. Let's take a look at that in 3D to have a better understanding of how that storage room fits into the stair. Here we see our person standing on the bottom floor where we had the up arrow.

We can see the stairs running up to the landing and continuing up from there. We will have our break line right around here. Can you also see the door behind this person? That is the door to our storage space.

Here you can see the storage room under the stairs. If we cut our stairs higher up, say here, we wouldn't have been able to see any of the storage space. Now you can see the bottom of the door and the break line for the stair.

Storage rooms under stairs are tricky to understand on plans, but just remember that they will not be full height spaces, especially right next to the break line on the floor plan. Again, from the top-down Plan View, we can see the break line location here and the storage room. And when this snaps into plan view, it's very tricky to understand from this single drawing what is a partial height space and what is a full height space.

So make sure that you look at the other drawings in your drawing set to get the full picture.