Framing - Positioning top and bottom plates

Hello,

Maybe I'm just overthinking this entire thing but I'm having a hard time understanding how to line up and square a standard partition wall. All instructions say to snap a chalk line, but never really talk about ensuring it's 'straight'.

Say you want to frame a wall that's 8' out parallel from the foundation wall (say for an 8 x 8 room). If the foundation wall is perfectly square and straight I would assume you would establish the plate position by measuring out 8' from the foundation wall at both ends of the plate position, and then run a chalk line. Is that the correct assumption in this case?

What if the foundation wall runs on more of angle? Say if the shape of the foundation was more of 'rhombus' than a rectangle. How do establish the plate position when your end measurements are not equal? Obviously you want the wall squared and not following the angle of the foundation, correct?

Again, maybe I'm just overthinking but I really want to know how these initial positions are established properly.

Thanks!

 

First, there isn't a square corner anywhere, they all are just close guesses.

The way to check for a 90 angle is the 3-4-5 rule. Measure 3 feet along one wall, then measure 4 feet out on the perpendicular wall. The hypotenuse of those two measurements will be 5 feet for a wall at 90 degrees.

 

First, if your foundation is not square you are off to a bad start.
Second, if the sill plate and deck on top of that foundation was not adjusted to be square (or exactly where it is supposed to be) then you have compounded that "bad".

But, since you are where you are, the best you can do is adjust as needed to get the room sizes you want on top of the platform you have. The difficulty arises when resulting ceilings and walls are not square where dimensional materials no longer fall on studs of joists as needed. The results would be wasted materials and TIME and poor construction.

If I were brought in at this point I would first apply the thinking czizzi explained and sketch out exactly what is there, sides, angles and framing members. On that sketch (hope you are good with geometry) I would apply all of my desired measurements and locate where studs will need to go, t-walls, windows, doors, corners, and all ceiling joists.

Unfortunately, framing is a far more involved process than just standing up walls and if you do not have a handle on it the bad gets worse at every step.

Do you know anyone skilled at framing?

Bud

 

Floor plans are two dimensional. You snap lines on the floor to denote where the bottom plate goes, then you plumb up.