How to find angle of sloped ceiling for partition wall

[terrilorr]

Hello DIYers,

Sorry not the best photo but I'm hoping to put up a stud across this room where the cables are currently hanging. Can anybody please help with how I would find the angle to cut the top plate for where the sloped ceiling meets the flat ceiling, and same again for the sloped ceiling plate meeting the wall vertical?

 

[GhostIntMachine]

Use a sliding bevel and a protractor. The basevline you work from must be bang on plumb). This is one area where a laser line is a boon

Quick and dirty alternative: set the line up the wall (again, laser) then over the ceiling (ditto, laser). Measure 1 metre down from the junction between the ceiling and the wall, mark the point on the line. Measure 1 metre across the ceiling from the same point qnd mark that on the ceiling line. Get someone to hold one end of the tap against the mark on the wall and measure to the mark on the ceiling. Mark the left side of the PB at 1 metre from the bottom corner. Use that mark for the hook on the tape and holding a pencil at the 1 metre mark on the tape draw a semi circle on the face of the PB pivoting from the mark. Use the bottom LH corner as a pivot point and hook the tape over that. Using a pencil held on the tape at the distance from the mark on the wall to the mark on the ceiling draw another arc on the face if the PB which bisects the firstvarc you drew. Use a straight line (chalk line, timber batten, etc) to connect the mark on the edge of the board to the cross you drew (whete the arcs bisected) and continue to the other edge of the board. You now have a line to cut to and you can transfer the angle to any timber studwork using - a sliding bevel

Basic 3rd year geometry

 

[freddiemercurystwin]

Draw a horizontal line say 300mm long where the red line is. Measure the blue line distance (vertically). Then report back and I'll tell you the angle between the green & the red line and the angle between the green & blue line.

 

[GhostIntMachine]

Then report back and I'll tell you the angle between the green & the red line and the angle ...

You must be a surveyor. In the real world you just don't need the actual angles for a job like this.

 

[freddiemercurystwin]

He asked for the angles, simple maths, I'm happy to oblige.

 

[Harry Bloomfield]

Most smart phones, include an angle gauge. Place the phone, alongside a bit of timber, timber up to the ceiling, and read the angle off the phone. The timber helps to ensure you get an average of the ceilings plaster angle.

 

[Deluks]

Get someone to hold a piece of studding against the sloped ceiling. Hold a spirit level vertically against the timber, check the bubble is centered and mark the timber.

Cut along this line, everything else can be measured off of that.
If you haven't got a sliding bevel, make a simple one by screwing two small strips of timber together at one end.

 

[foxhole]

You don’t need angle just measurements .