I don't understand this house plan

Hi everybody.

I found this house plan through images.google.com.

But there are things I don’t understand what they mean or what they are for, what it really makes me confused is the door.


if that door is in the first floor what is it for?

Looks like the following, to me…

The door is on the main floor, opening to stairs to the basement.

That is a wall, but one with a sloped top and a railing going up to the second floor.

The Double dotted lines seem to represent a beam.

The single dotted line seeme to represent the line of the floor above.


Thank you @TheOnlyAaron.

I’m processing your review.
I also thought about that door lets you pass to the basement but … the basement isn’t in the plan, right?
I was to make sure.
I agree with the double dotted line representing a beam

About the second floor, how do you access to the red cross? because I see a railing that’s blocking your pass.


One thing more.

Do the railing start where the stairs start?

Aaron is of course point on.

The meaning of lines varies across countries and different standards. In our parts this would read as a plan for alterations in an existing structure. The black fill means the walls are existing ones. The dashed lines would indicate a wall or a beam that is below the floor, in the basement. The dotted line would indicate that something existing is going to be demolished.

The basement stair ought to have a landing at the upper end. A door should never open directly into a staircase.


Hehe, I think I’ve seen in several movies doors that open directly into a staircase where the basement is, but I agree it’s dangerous.

If only there was a simple way to represent that 2d drawing in 3D… Oh Wait a minute!!

Something like this…


Thank you so much again @TheOnlyAaron

I was about to upload three possibilities some of them made no sense when I see them once they’re drawn.

According to your picture the “wall” with a sloped top and a railing should start from the beginning of the walls till the end as in this picture?


Generally, this is something that I would look for an interior elevation or detail or section for, but a lot of times the stair wall would look something like this:

I was thinking in something like this (but yours looks like a better solution):


EIther way is valid… LIke I said, that’s where details come into play. With JUST a plan, you have to guess how a lot of that will work.

You’re right.

While it’s true it could go either way, in this case it’s almost certain to look like this for structural reasons. Where the full height wall ends supports an outside corner of second floor framing. If you look at Aaron’s model, there’s a corner hanging in the air. Not that you couldn’t do that, but it’s not as simple to frame.

Thank you RTCool.
The true is I know nothing about designs, but I was taking a look at images.google.com and there are all kind of internal stairs. I guess the point here is that a 2D plan like than with no more details can be interpreted in several ways.

The unsupported corner reminded me of a real life experience! I own a summer cottage in Maine that was built about 1904. There is lots of evidence that the carpenters just sort of winged it, making up the design as they went along. One example is the stairway to the second floor. It looks like they built the opening for the stairs and then decided they would be too steep. So they sawed off a joist across the end of the opening and redid the stairs to land against the next joist. But the rim joist that carries the ends of the joists on one side of the opening was supposed to attach to the joist they sawed off! So it produced a corner hanging in space like in @TheOnlyAaron’s model. To compensate, they overbuilt the stair stringers with much wider stock than normal. But over 100+ years the inevitable happened: that side of the upstairs hall settled and now the floor is sloped! I put in a new beam and studs to support it, but the sag remains as a reminder.

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Yeah, it’s incredible sometimes what I find people have done and amazingly, the thing’s still standing. Plumbers especially hack away at framing members to run plumbing drains that virtually leave the member worthless.

If they didn’t want plumbers and electricians to cut holes in it, they shouldn’t have made it out of something that a hole saw goes through so easily!

Funny how often I heard that, “The sheathing will hold that together.”

Another example! In my house at home (1886) when they added a bathroom at the front of the second floor they wanted to run a chase along a wall that happened to be right over the main carrying beam for the first floor. So they put a post (wooden, of course!) about a foot from the basement wall, sawed off the end of the beam, and attached a large L-bracket to keep the beam from moving sideways!

…and I’ll be the post is resting on something never designed to take such a point load at that spot.

You mean like dirt?

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