I am going to install 4 x 8 sheets of breadboard over a wavy popcorn ceiling and want to make sure the beadboard does not follow the waviness of the existing Sheetrock by first installing furring strips. If I were installing individual beadboards I would have to install the furring strips the entire length of each joist since I would want the boards in this particular room to run perpendicular to the joists but does it matter whether I nail the furring strips the length of the joists or perpendulicular to the joists if I am nailing 4 x 8 sheets to the strips? If I do run the furring strips perpendicular to the joists what spacing should I have between them? Also are 2 1/2 inch 16 gauge nails sufficient for keeping this ceiling in place? Thanks.

I would screw the firring strips in, unless your using an air nailer. Much faster than hammering a ton of nails.

I am going to assume that the words "Breadboard" and "Beadboard" are interchangeable and possibly regional pronunciations. Either way, the installation should be the same idea. I'm just not personally aware of the beveled type of board that you may be referencing, sold as a sheet goods.

First, if it's that wavy, you may want to consider scraping the popcorn off anyway. What part is wavy? The popcorn or the surface underneath? Scraping is messy, but super easy. Even if it's been painted. If there are "bumps' under the furring strips it will impact the job quality. Just a thought.

Why is it wavy? Are we talking wavy plaster? (maybe loose?) A bad sheetrock job? The only way I would consider your route is if it is crumbling plaster. If it's sheetrock I would re-screw the ceiling and finish appropriately. I realize that may not be possible for everyone. If it's crumbling plaster, you can't add too many screws or space your furring strips to close together. Overdo it for plaster.

To answer your question, I think it is a much better job to run the furring strips perpendicular to the ceiling joist, and then run the beadboard perpendicular to the furring strips. This will also help smooth out any possible sagging joist. If you have a nail gun it is easy to tack them up (2 1/2" / 3")ring shanks are best, and then follow up w some 3" screws. Use the exterior type that have a drill point on the end to avoid splitting. 16" on center is always best, but w sheet goods (and the screws I mentioned) you may get away w 24" spacing. There is a possibility of sagging and even failure w the 24" spacing and no screws (nails will lossen over time, especially if this is the bottom floor of a 2 story) 16" on center is always best.

Some other things to consider....

You can pull multiple strings and use shims to level out your furring strips. Painting that beadboard is a pain. I love it and used to put it everywhere. I regret that decision daily, but especially at turnover.

If you are using the solid wood, single board type of beadboard, they are subject to a lot of seasonal shrinking and swelling across it's width. This means lots of mystery gaps that come and go. It doesn't look that good, and caulking it only makes it look worse. I only use the sheet goods these days, if I am asked to install it. They sell a 3/8"x4'x8' sheet (of beadboard) that has much deeper groves than the 1/4" stuff. Use that if you want an authentic look.

I would choose options based on where the property is.. Recently I have used some 1/4" luan board as basement wall.. Then caulk the seams.. It worked out well for C hood type of properties..

If it is A/B, I would spend extra to get it fixed nicely..

IF you have some wavy to the ceiling then you my want to consider running the furring strips with the joist this may help hide some of the wavy. Check to make sure the drywall is against the joist. IF the trusses are on 24" centers then its understandable that there is some wavy to the ceiling. I doubt if you wanted to try to get the wavy out of the ceiling that the drywall (IF its drywall) would flex for this to happen.

In New England it's common to have 1x3 strapping applied 16" oc perpendicular to the ceiling joist which normally are themselves 16" oc. This give you the ability to make the ceiling straighter & flatter, allows space for wires to be run & helps reduce deflection in the joists. In other parts of the country you rarely see any strapping used instead the ceiling covering is applied directly to the joists.

In your case I would be inclined to use 1x3 strapping or possibly 2x4's applied 12" oc perpendicular to the existing ceiling joists. This should help eliminate some of the existing waviness particularly if it's caused by loose SR.

Make sure that you locate exactly where the current ceiling joists are before you start attaching the 1x3's. Depending upon how thick the existing ceiling is & whether there is already strapping, I would tack the 1x3's up with my nail gun then go back & add a screw to make sure the strapping is pulled up tight.

If you have enough ceiling height sometimes it's faster, easier & comes out flatter if you install metal track along the walls & use metal studs as new ceiling joists.

Are you planning to do any wiring, plumbing or insulation work before you install the new ceiling?

1. Remove the popcorn ceiling.

2. Determine the source of the waviness.

3. Eliminate the waviness, if possible.

4. I'd use screws only, long enough to go at least 1" into the joists. They don't pop as nails.

DeffDefinitely would use only screws for all strips and board on ceiling.

Steve's post reminded me of one recent project we did..

I don't like drop down ceilings and made a mission to remove all at turnover. We took down one from a kitchen which is about 14x14, old plastered ceiling got exposed and part of the it dipped 3-4" down. We guessed that it leaked at certain point of time, it had blow in insulation and too heavy to push it back up. It will become a messy project if we tear down that part of ceiling..