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Cathedral Ceiling Framing

Shaken-n-stirred's picture

Cathedral Ceiling Framing (post #215124)

New Construction.  2 x 12 rafters.  eyeballing underside of rafters looks nice, of course who can see 1 /4 inch sag or rise.

Need to nail nailer to gable wall to plane with rafters for dry wall blocking.  REad next post if this one is not blown out by spam filter



Edited to to add other post.

IF I measure down from the underside of teh roof deck 11 1/8 inches (width of rafter) and then check this location on the wall with a level accross 2 or 3 raftes further in on the ceiling teh 11 1/8 inch marks various as being off anywhere from zero to 1/2 inch!

What is best practice here?  Use teh plane of the adjasent rafters? Use and average?  Use the 11 1/8 mark?

Shiming or strapping is going to be nearly impossible for me given teh ceiling is 20 feet to teh ridge and I have no scaffoldimng.

1.  how to proceed with nailer

2  will i notice a waving ceiling once sheetrocked?

like i said eyeballing the underside looks nice.

wierd? (post #215124, reply #1 of 15)

Anyone?  Buuulerrrrr?

I am sorry. Your description (post #215124, reply #2 of 15)

I am sorry. Your description is too vague and don't want to hurt your feelings saying more. Why not send a photo and do a re-write? I am at a loss visualizing what you are trying to describe. Others probably feel as I do and hence the lack of responses. Thanks

Mel Fros

Pretty Basic (post #215124, reply #3 of 15)

New construction.  2 x 12 rafters.  I will assume people know what a rafter is.  Cathedral ceiling, ie not a flat ceiling but a sloped ceiling.

There is no place to nail the ceiling drywall up against the gable wall.  (Wall was framed with 2 x 6 look-out on top, no 2x12 rafter in place against the framed wall.  Thus there is nothing to nail the ceiling drywall too)  So obviously, or perhaps not so obvious for some, I need a nailer nailed to this gable wall to receive the drywall.

If I measure down from the roof deck at the wall the width of a 2 x 12 rafter that should be in plane with the ceiling rafters elsewehere in the roof.  IT IS NOT!  It is off by as much as 1/2 an inch.  This seems odd since the rafters all look pretty good as far as theh eye can tell by sighting accross the bottom of them.

Suggestions as to where to nail the nailer?  Use the 11 1/8 (rafter width) and let the chips fall where they may?  Use the level to plane over from two or three adjescent rafters and follow that lead?  Other suggestions?

Hope that is clear

Wall (post #215124, reply #4 of 15)

So the gable end wall is framed all the way to the roof deck and doesn't have a rafter on top of it? Normally there would be a rafter on top and drywall backing nailed to the top of the wall. 

"normal" ? (post #215124, reply #10 of 15)

If it is normal to frame a gable wall and place a rafter on top, how is it "normally" done to then support the barg ? Varg? fly-rafter on the over hang/

I have seen six inch blocks nailed to teh rafter of which you speak and the facisa 'rafter" nailed to teh block.  But if the over hang is long this would not work.

I ahve also seen a rafter installed as you have suggested and a notch made in teh top fothe rafter to accomadate a 2 x 4 lookout on the flat to support the Barge, but that too can be a bit weak if the overhange is 24 or more inches and in snow country.

In my case I have 2 x 12 rafters and a 2 x 12 Barge/fly rafter out 30 inches.  Therefore the framer used 2 x 6 look outs on edge over the gable wall (actually much like a drop truss) to carry teh fly rafter .  ( also built and installed corbels to carry some load )

Curious as to whether this is unusal.

Pretty basic. (post #215124, reply #6 of 15)

Since you see something as bad as a half inch, you might want to get a couple more ladders on the job and a helper.

string a line across the room with that helper and use a 3/4 " gauge block at each end to bring that line below the worst rafters.  Pull tight and look at your helper.   Find the offending rafters and then think how you want to make it disappear.

once you figure that out, use that straight edge you have and transfer the bottom of rafter to a stud at the wall and ridge.  Strike a chalk line along the wall studs and nail off that drywall catcher to that line.

you can do the above solo but it's a lot of ups and downs on the ladder.  


If you have a laser line level that you can lock out as a straight line, project that fastened to fastened gauge blocks at the ridge and wall, find the offending rafters and deal with it.

the line or laser may tell you everything's ok.  If so, go to the chalk line step and strike a line on the studs from wall to ridge.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Thanks Calvin (post #215124, reply #8 of 15)

Yes, I suppose I should run the string across teh under side of the rafter at mid span to start with and see what I see.  As I said, they sure look nice when I sight teh under side from a catwalk I have on one end of teh room looking toward teh gable.  But I am sure it is tough to see rafter out of plain unless it is just one lone rafter which is way out of wack.

And don't I know about solo work.  That is about all I do and some jobs are about ten times longer than just having more more guy around.

 If I measure down from the (post #215124, reply #7 of 15)

 If I measure down from the roof deck at the wall the width of a 2 x 12 rafter that should be in plane with the ceiling rafters elsewehere in the roof. 

A roof has rafters and a ceiling has ceiling JOISTS.  I am confused!

What I am having trouble visualizing is where the problem occurs. have a gable roof with opposite and facing rafters lying on walls and reaching upward to meet at the ridge beam. Yes? There is a load-bearing wall below this ridge beam/board. Is that correct? 

I do not fully understand where the problem occurs: up there near the ridge, or midway down? I can offer solutions for each senario. Sorry if I seem noodle-headed,, but a clear descriptions is essential... for me. Thanks.

 I'll await your response before I share my tricks of the trade.

Mel Fros

Unless that ceiling is a cathedral (post #215124, reply #9 of 15)

A roof has rafters and a ceiling has Joists. Unless that ceiling is a cathedral in which case the CEILING drywall is nailed or screwed to the underside of RAFTERs.  prehaps that is still called a joist, but I would think to call it that would imply a horizontal ceiling, which I do not have.  What is industry standard.

Ok.  Ridge Glulam , no support wall at ridge, except obviously gable walls supporting the beam.

Rafters tie into the suporting ten foot side walls at the low end of the rafters within reasonable tolerances.  Rafters tie into the ridge also reasonably well. 

So the problem is mid span.

It seems to me one of two things is occuring.

First, it could be I have a rafter in from the gable wall with a major crown or sag.

Secondly, since there is no rafter at the gable wall itself (the gable wall was framed 5 1/2 inches short of the roof deck so that 2 x 6 lookout could run over the wall to carry the Varg ( or is that Barg or fly ) rafter ) the gabel wall could have been framed high or low and therefore if I measure down the 11 and 1/8 inch it makes it appear to be way out of plane with the rest of the underside of the rafters.

From the  outside the roof looks nice with no visible hump or dip at the gable wall so you would not think the wall was mis-framed.

 I suppose no of this matters ... a nailer must be install so as to run in plane with the rest of the rafters regardless of where teh 11 1/8 inch  measurement falls.

I think Calvin stated teh obvious, that I just need to look the whole ceiling plane over and see if I have a rafter or two with a major crown of sag throwing me off.  If so "fix" it with shims or something.  SUGGESTIONS APPRECIATED.

power plane the rafters (post #215124, reply #11 of 15)

I'm going to focus my comment on irregularities near the center of rafter spans. I suppose this is one area where sags occur. Snap a chalk lines across the length of each rafter, making sure that you measure equi-distance at both the gable and the lower support wall. Now power plane each rafter as needed. Obviously, you don't want to plane out too much, so you may have to "cheat" a little. 

SIDE NOTE: Here's a nifty idea that helps me mask framing irregularities: I place my drywall butt-joints between (not on) rafters (trusses). Each joint is backed by 1/2" thick x 6" wide x 49" long piece of OSB, which has been mudded (USG "green" taping compound only...not "lite") and screwed into place. Using a 1x6x50", two scrap pieces of 2x4x 26" and sturdy screws, I fashion a simple clamp that pushes the joint into the rafter bay by 1/8" (not more). This privides a bevel joint for taping. I get excellent results and, most often, don't need to texture the ceiling. Texture, I will add, goes a long way to hiding irregularities. I prefer to make and apply my own textures, using USG Green taping compound and silica sand. 

Mel Fros

Power plane? (post #215124, reply #12 of 15)

Yes dimension lumber is interesting to work with.

I framed my first floor over crawl with 2 x 10s.  I worked the entire structure over with a power planer before laying the deck.  I was surprised to see teh crown on the joists varied so much.  A bit of a pain but it should pay off when laying hardwood.

I did the second floor with BCIs.  They are flatter.  I used 2 x10 on the firsat floor as I was not sure how dried in I would be and feared mold.  As it turned out I was right.  The underside of about 2/3 of the subfloor grew mold before I was dried in.  the 2x10 were clear as new.  I hate osb as it molds just looking at it.  I think BCIs in the crawl would have been a mess.

now plnaer plane teh underside of my rafters in a 21 foot cathedral space????????????????????????

Not pretty .  I will look very closely and them and see if I roll the dice and see if I think I will not notice wavey drywall.

1x4s and shims (post #215124, reply #13 of 15)

You can smooth things with 1x4s spaced 16 OC; shimmed as needed. 16" OC.  spacing allows you to use 1/2" drywall instead of the customary 5/8". No matter what method you use, you will be spending considerable time leveling. Ultimately, what you do depends on the result you wish to achieve. Remember that ceilings are unforgiving in the sense that they are far more likely to show defects than do walls. 

NOTE: blocking won't help much.

Mel Fros

S (post #215124, reply #14 of 15)

At the end walls after you check the flat ....

chalk a line from wall to ridge and hold your nailer to that line.  Waves show up big time to those who look where wall meets ceiling.

I use a plastic bead from Trimtex

at bottom of the rafter/wall.  Chalk a line on the wall after the board is hung where you want the bottom of the bead to go.  I spray adhesive the bead to that line.  Dead on perfect line that also eliminates potential cracks at that joint.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Use a straight edge on the (post #215124, reply #5 of 15)

Use a straight edge on the bottom of the rafters to transfer a line over to the gable and use that as the bottom of your nailer.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

laser and shim to light (post #215124, reply #15 of 15)

laser and shim to light