# Mark 2 points on parallel walls directly opposite each other

I am about to mount some steel pipe which spans from one wall of a room to the opposite wall. (Here's why: Mount Pull-up bar from wall to wall)

How do I accurately mark two points on facing parallel walls so that the points are directly opposite each other? By directly opposite, I mean that the line joining the points should be horizontal and should also be perpendicular to both walls.

Additionally, I have a hook suspended from my ceiling and it would be nice if I could accurately mark the points so that the line joining them passes directly below this hook in addition to being level and perpendicular to the walls.

• A string. Put a small screw or nail on the heihgt you require on one wall, then pull a string across, use a water level (make sure the water level is correct, always mesause twice, rotating the level, even doing it upside down, I have seen too many water levels being incorrect) Once the string is as desired on the other wall, mark it. Taadaah. Commented May 9, 2015 at 22:38
• Did you ever get this resolved? If so, please give a check-mark to the answer that helped you the most, or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer. Commented Aug 10, 2020 at 17:53

Why not buy the pipe, and make the marks based on that. That is, have a level, hold the pipe up and level it, then mark where it touches the wall. A friend would help, so might hanging or otherwise supporting the pipe from either above or below as you do this.

I guarantee the walls are not parallel but you may not notice it. Point is being off a 1/4" or so in any direction for something like that is not going to be a problem. Just measure up, and measure over from the nearest wall on each side. Probably be more accurate that way than a level if you are not used to using a level.

We'd just shoot our laser on it with a horizontal self leveling plane.

• Not a good idea if it MUST be level. The floor may be 1cm~3cm out on opposite walls. If its critial, then yea, laser it, technologic. But then again because of skew walls and floors, something that is ideally level, will visually look unlevel, something that is not obvcious to DIY'ers, cause, visually everything looks OK in a house.. but in reality some houses are horribly deformed. SO it all depends what the end result is supposed to be. I painted horizontal lines skew so many times and people were amazed by how straight they were. Magic! Commented May 9, 2015 at 22:41

Take a laser pointer mount it on wooden square (4x4x1 cm)piece perpendicularly by making hole in center and fix it. Now place on the wall at desired height laser points exactly horizontal on opposite wall. That's it. LASER travel straight line.

Get a tube file it with water, a water always finds its level. This old house will have a clip on how to do it.

• Welcome to Home Improvement. If you'll take a look at the help center on answering, you'll see that we're looking for something a little more substantial than "go google it". There's nothing wrong with including a link to a video that demonstrates what you're suggesting. If you would describe how to make and use a water level, along with a link to one in use (or a recommendation on where to find one in use, like on This Old House), that would go a long way toward improving your answer. Commented Aug 10, 2020 at 17:56