# Flatten uneven sloped ceiling



## Mr_Stop (Aug 15, 2016)

I need to flatten an uneven ceiling (consisting of poorly set trusses) to prepare for drywall. It is sloped on the edges and flat in the center. I'm running strapping perpendicular to the trusses with shims underneath. The flat was easy as I set my laser as a horizontal reference line and shimmed the strapping to the low spot. 

Since my laser is self leveling, I can't set it for an angle and I'm having a hard time visualizing how to do the sloped sides. The sloped ceiling is about 4' wide and 30' long.


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## META (Apr 9, 2015)

I've strung line on the slope I need and then shim as needed.

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## Mr_Stop (Aug 15, 2016)

I have been thinking about using a stringline. I have done that for walls before. It seems like I would need to run a separate line parallel to each truss with perpendicular lines to even them up creating some sort of grid. It sounds like a lot of work. Am I overt thinking this?


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## META (Apr 9, 2015)

Mr_Stop said:


> I have been thinking about using a stringline. I have done that for walls before. It seems like I would need to run a separate line parallel to each truss with perpendicular lines to even them up creating some sort of grid. It sounds like a lot of work. Am I overt thinking this?


How much are you actually needing to shim out? Do you have room for 3/4" sleepers?

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## Mr_Stop (Aug 15, 2016)

If the sloped sides are like the flat ceiling, there is up to an inch or so difference between the high an low spots. I'm running 1x3 strapping perpendicular to the trusses. 



As I talk through it, I could probably just set a board at each end to the slope i need and run a string line above each piece of strapping. There are just 4 boards, so it shouldn't be as bad as I was thinking.


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## META (Apr 9, 2015)

I think you're onto the correct direction. 

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## Tom M (Jan 3, 2007)

Mr_Stop said:


> If the sloped sides are like the flat ceiling, there is up to an inch or so difference between the high an low spots. I'm running 1x3 strapping perpendicular to the trusses.
> 
> 
> 
> As I talk through it, I could probably just set a board at each end to the slope i need and run a string line above each piece of strapping. There are just 4 boards, so it shouldn't be as bad as I was thinking.


The ***** is usually you think to run a string high end to end then low end to end but the mid section is bellied from deflection or sag.

Maybe that doesnt apply to your trusses but try the high and low string and maybe a steel stud straight edge to check the middle


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## Tinstaafl (Jan 6, 2008)

I don't have a self-leveling laser, but know they can be locked for transport. If it will light up in locked mode, couldn't you just use the beam as a stringline?


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## Railman (Jan 19, 2008)

Stretch string 30' at edge of strapping, raise string 1/8" at center (for string sag comp.) & fasten, gap shims/strapping string 1/16" so that nothing ever touches string. Letting shims touch string is where most people mess up. It will give an accumulative error from repetition. It might be easier to just shim each short truss section, instead of strapping entire section. You just need a selection of 1/8" to 3/4" rips. Result will be way better than 99% of most ceilings.
Never let anything touch a straight line string!


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## Big Johnson (Jun 2, 2017)

I’d hire tipi to fix it.


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## Mr_Stop (Aug 15, 2016)

Thanks for the help! I think I got it. Sometimes, it just takes a bit of talking (or typing) through the issue. 



My Dewalt laser doesn't lock. Definitely will look for that feature on my next one though.


Tipi is welcome anytime, as long as his work is better than his writing....


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## META (Apr 9, 2015)

My Hilti Green laser locks, but it'd be a pain to get a 30' plane without fine tune multi axis adapter. 

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## Tom M (Jan 3, 2007)

My laser has a fixed mode as well.

It should be common knowledge to gap the string for sight purposes.

After weighing out the heart of the problem I often ditch all shimming and bust out the electric planer.


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## Railman (Jan 19, 2008)

Tom M said:


> My laser has a fixed mode as well.
> 
> It should be common knowledge to gap the string for sight purposes.
> 
> After weighing out the heart of the problem I often ditch all shimming and bust out the electric planer.


I believe he said up to 2"...lots of shavings!:whistling


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## Tom M (Jan 3, 2007)

Railman said:


> I believe he said up to 2"...lots of shavings!:whistling


I didn't catch that.


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## Mr_Stop (Aug 15, 2016)

It was about 1", but still don't want to take a 2x4 truss down that far!


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## Fouthgeneration (Jan 7, 2014)

Find the LOWEST angled truss with the laser ...Set the laser to the TOP of the slope, snap a chalk line parallel(at the same distance as the lowest truss is from plate) to low end wall plates, Scab on a 2x4 or 6" to the high legs , setting the top end, the bottom to plate, unless you are "fixing" the roller coaster top plate height?

TWO scabbed on boards at at DWall butt joints? or cut shim for under butt joint....


If the home is more then a half inch out of level.... you might have better luck with string lines, instead of a self-leveling laser. i got a cheap < [email protected] home depot laser that is hand leveled with spirit bubbles instead of gravity pendulum, so you can set it out of level with care.


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## tipitop (Dec 3, 2013)

Big Johnson said:


> I’d hire tipi to fix it.


Thanks for it, proof below. Imagine only 20 years back I wold not be capable to prove I can do it. No cameras in phone, not forums etc...


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## tipitop (Dec 3, 2013)

Railman said:


> I believe he said up to 2"...lots of shavings!:whistling


Shavings???? Did you ever heard about Dock Holliday? Cold blooded hand and table saw?


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## AustinDB (Sep 11, 2006)

there is a lightweight string used for drop ceiling installations-would work great here. I also use a 10' piece of extruded aluminum channel to find low/high spots when doing something like this. 

the 2x4 or 2x6 is quick and easy for this job-ensure you have enough nails holding it onto the truss so the sheetrock doesn't pull it off.


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