Establishing a straight line on a cathedral ceiling
RenovatingRedhead
| Posted in Construction Techniques on
Hello, I’m new to the forum and am looking for carpentry/building advice.
I am making faux wood beams for my cathedral ceiling in the MB – 4 sets of beams, no ridge beam. I can’t figure out how to establish a reference line on the peaked ceiling that is straight and square on which to align my first beam. None of the four corners of the room is a perfect 90. All of the walls have a slight bow both horizontally and vertically. The end walls aren’t straight. The side walls aren’t straight. So how do I establish a straight reference line and somehow transfer that to a peaked ceiling? The room is 14 x 11. Geometry was never my strong suit.
I will post a diagram of what I mean.
Replies
diagram of how to align beams in a crooked room
Diagram to illustrate my question of how to alignbeams straight in a crooked room with a vaulted ceiling.
is you concern the ridge (labeled peak) and finding a consistent line between wall 2 & 4?
if so, you wont be able to hide the fact that the peak is wavy or that your beams are "aligning" at different points, you could just add one more beam to your project and set a ridge beam and avoid those issuse.
Hi Mark 122 The wavey peak isn't my worry
I'm more concerned with the beams being straight and aligning to each other. I am mounting the beams paralell with the end walls, #2 and #4 in my diagram, but those end walls are crooked. So I will have to mount the first set of beams at some (as yet) unknown distance from the wall to establish a straight line/plane. So how do I detemine that straight line/plane? I will likely have some filling to do between the end wall and the beams.
you will either have to go with precise spacing or aesthically pleasing spacing then. Plan your layout on paper. figure your theoretical spacing between beams and then compensate for crooked walls. You will notice your crooked walls at wall 2 & 4, so when you get there you will need some creativity.
maybe pulling those beams off the walls in question a bit so that the crooked walls are not as noticable. depending on how crooked they are some separation between wall and beam may be enough to trick your eye a bit.
another option would be to have a beam at walls 2 & 4 that look like they are inbeded in the wall. not sure if that makes sense. you could make those beams 2 sided vs 3 sided making it look like your walls 2&4 are supporting the beams.
either way you will have some compromising to do that can not be avoided, just a matter of where the compromising will be.
One trick you might use is to hold the end beams off the end walls a foot or so, then paint the area up to the gable wall (and possibly part of the wall itself) a dark color. This will tend to conceal the irregularities.
There are several other tricks you can play with paint, such as painting a (straight) stripe maybe 6-8 inches wide along the peak, to conceal how crooked it is.
Mark
below is a link to a job I did. Layed out paneled ceiling in a bogus room on the floor. Kept the layout perfect, scribed the perimeter to the "bogus" wall lines. Was able to adjust the perfect layout to the line of walls so there was no visible (readily) "bogusness" in the finish.
the squaring dot laser projected layout points to the ceiling, the line laser completed the layout lines. Chalk lines struck. Fill in the finish.
http://www.quittintime.com/ubbthreads/showflat.php/Cat/0/Number/10953/an/0/page/0#Post10953
Well, of course, with your situation "straight" is relative.
But I'd first try to establish a horizontal line (string) running from one side to the other, something that I'd consider "square". Then drop a plumb line down from the peak and find where it just touches your horizontal line. Mark that at the peak and (conceptually, at least) draw a line down from that mark to each end of your horizontal. Your beams should then be made parallel to that line.
Hi DanH tell me if I understand you correctly
So thinking about this in terms of my diagram, I should run a string line between wall 1 and wall 3, right.? On the floor, or overhead?
Then when you say drop a plumbline from the peak - from any point along the peak?
I don't get what you mean "draw a line down from that mark to each end of your horizontal"
I'd probably make the first line from the top of one wall to the top of the other, right where the wall and sloping ceiling meet. Then the weighted line from the ridge is dropped and you move it back and forth along the ridge until it's just touching your first line, meaning you've found a point on the ridge directly above the first line. Mark that point on the ridge.
Then a line drawn, on the sloping ceiling, from the point you just marked on the ridge to the ends of horizontal line will be as "square" as you're going to get. You should only need to do this once (or maybe once near each end to check yourself) then measure off equal distances from the lines to place your beams.
If your ridge is really that "unstraight", it might be best to install a straight ridge board that conceals the actual ridge a bit and establishes a straight line down the ridge.
RR
could you tell me which direction these faux beams are going to run?
and do you have a line laser you could use?
remember no remodel conditions are perfect, your job will be to fool the eye.
I Was Gonna Suggest a Laser...
... seeing as how they're really inexpensive now. Considering all the time, effort, and expense for materials in such a project the cost for one of these is trivial compared to the risk and complexity of doing something unfamiliar with strings and plumb-bobs.
I used one when I laid out then built a set of hardwood stairs (7 steps to landing, another 7 on to the 2nd floor) with housed stringers (mortised in treads & risers) last year for the first time. Once completed and installed a digital angle reader told me everything was level & plumb to 0.1 degree, which was gratifying.
I bought a laser, now what?
I bought a laser, now where do I start?
Red
Where do the beams run?
If the laser can be made to spin with the axis of spin horizontal rather than vertical, then you can use it the same as my two strings and a plumb bob (without having to climb a ladder). Have it paint a line up one side of the ceiling and down the other, and regard that line as the route for your beams.
My recommendation would be to.....
find the adjusted center of the space (each way) and layout from there. Make the beams right with themselves, adjust to a happy medium their relationship to the existing b/4 you begin.
The beauty of both a dot and line laser......
Is that it enables one person to show temporary lines or spots when doing layout. Couple that with tape with marks and you can do preliminary figuring w/o marring the finished surface.
in the op's case, she should use them to find centers square to themselves in order to adjust the placement of the faux beams to make them "right to themselves". Minimize the "goofiness" of what's right compared to the existing.
fool the eye!
To all helpful responders
Thinking about all the suggestions you've given me I've come up with an idea for making a straight reference line. The walls and ceiling are wonky but maybe the floor is better. I happened to notice that on the bare plywood floor in that room there is a seam running between the 4'x8' sheets of plywood that goes from side to side. Assuming that the sheets of plywood are square/straight maybe I could transfer that line to the ceiling using my laser.
I am thinking to hold the laser along points on the seam to shine dots or a line on the ceiling and have a helper mark those. Then snap a chalkline across them to average out any anomalies. Then I'd have a reference line on the ceiling from which to measure/square from.
What do you think? Picture of floor seam attached.
Seams like a possible approach.
Red
adjust the control line on the floor so it is in line with what you want to do on the ceiling. Lay it all out, strike the lines on the floor to plum up. Spray the lines with a can of clear lacquer, they'll last through all the work and sweepings.
Mark
It's easy being in the biz, takes a bit of work to last.
i will admit that I 'm glad I concentrated on the total reno area instead of specializing on only a part. Way more rewarding to the head.
thanks.