How to straighten a ceiling

[flyfisherman]

Hello. I'm about to level a ceiling where the rafters are "Polish-built" on site, meaning there isn't a right angle anywhere, and when you lay a straightedge across the spacing boards you see differences of up to 15 mm. The spacing panel is screwed with plastic and insulation on top. I'm thinking of measuring where the ceiling is lowest and then loosening screws and placing spacers between the spacing boards and the rafter. But how should I measure it? I have no experience with lasers, could that work? Or does anyone have any other tips?

 

[anaitis]

Transparent plastic hose!
With a bit of colored liquid inside for easy reading.
Have used mixed saft...

 

[Mikael_L]

The laser equipment I can think of that works is a rotary laser with a receiver and some kind of measuring rod (which in this case can be homemade from a piece of wood lath).
But it's not particularly cheap equipment.

You place the laser near the ceiling somewhere it has a clear line of sight everywhere.
Then you choose the new level of the ceiling and set the measuring rod and receiver to this height.

Then you place the measuring rod against each point where you wish to set the height and adjust until it matches.

 

[flyfisherman]

Thanks for the tip. That sounds easy. I will try it. Expensive yes. 9000 kr according to information. But maybe there is equipment to rent.

 

[Stefan N]

Rotary lasers are available cheaper. Bosch GLL-80 for example. You can also use it for other purposes.

 

[Daniel78]

I usually use a rotary laser and a piece of batten with a decimeter folding rule/tape measure taped onto it.

I have a cheap Black & Decker rotary laser which I hang from the ceiling at roughly eye level. Then, just set the batten against a furring strip and read a measurement, find the lowest furring strip, and move the tape measure/folding rule so that you have the laser line at 0mm on the lowest furring strip.

Then go around with the batten and read off the measurements, writing directly on the furring strip how many mm it differs. After measuring everything, just go around and insert shims/packers. I've adjusted both ceilings and floors this way, and it's relatively quick.

 

[Daniel78]

Bosch also has a green rotary laser:
http://www.clasohlson.se/Product/Product.aspx?id=158778556

 

[Hubbe2]

There are cheap rotary lasers that do the job well enough, around a thousand. Hang it from the ceiling in the middle and then walk around with a ruler to check the heights you have from the line to the sparse panel and adjust accordingly.

 

[Skumpen]

Start from the floor, level the four corners, use a spirit level and straightedge, place masonite or other spacers so the corners are even. Measure up to the ceiling from these four points and between these four points, stretch a string. As you add supports, tighten up new strings while keeping the old strings as reference. Difficult to explain, hope you understood. String is cheap, you probably have a level and a board as a straightedge max 100:- kr.

 

[flyfisherman]

There are rotary lasers available for rent at Ramirent for a few hundred kronor. So that's what I'll do. Does anyone have any tips about underlays? I usually use masonite, but are there special spacers with different thicknesses? I seem to remember seeing something about it on TV, but can't find anything when I search online.

 

[Gnor]

Transparent plastic tubing! With a bit of colored liquid in it to easily read off. Have used mixed juice...

Why all the talk about lasers when old reliable technology works just fine. As Anaitis has already suggested. At least for one-time jobs, if you don't want to spend money on a laser.

 

[flyfisherman]

Why so much talk about lasers when good old-fashioned technology works just fine. As Anaitis has already suggested. At least for one-time jobs, if you don't want to spend money on a laser.

I used the hose method for a house foundation in the late '70s. I found it awkward and time-consuming with the water level in the hose that never settled, and in the end, I had to check the result with a leveling instrument. And adjust. I might have done it wrong then, but it feels safer with the laser.

 

[Mats]

With a slang, you take it easy, but if you do it right and ensure there are no air bubbles, the slang is unbeatable. It measures better than even an expensive laser.

 

[Mikael_L]

I usually use a rotary laser and a piece of batten with a decimeter ruler/tape measure taped on. I have a cheap Black & Decker rotary laser which I usually hang from the ceiling at eye level, then you just place the batten against a sparse panel and take a measurement, then find the lowest beam and move the tape measure/ruler so you have the laser line at 0mm on the lowest beam. Then go around with the batten and read what measurement you get and write directly on the beam how many mm it differs, when you've measured all of them it's just about going around and placing shims/wedges, I've adjusted both ceilings and floors this way and it's relatively quick.

That's not a bad method. With that method, you can even use a cheap line laser, as long as you mark a reference point when you move it to a new sweep area.

 

[Daniel78]

There are rotary lasers for rent at Ramirent for a few hundred kronor. So that's what I will do. Does anyone have tips on underlays? I usually use masonite, but are there special spacers with different thicknesses? I seem to recall seeing something about it on TV, but can't find anything when I search online.

I use these two products when aligning floors, walls, and ceilings, and also when installing windows, doors, etc.

http://www.haraldnyborg.se/merinfo.asp?varenr=4509&n=10
http://www.haraldnyborg.se/merinfo.asp?varenr=4512&n=10

The spacer discs are very convenient to use once you've learned what size each color represents. The discs are available in 1-5mm and have guides so you can stack them inside each other. When it exceeds 15-20mm, I use the wedges instead.