Expert: Dan Griffin - 3/25/2009

Question
QUESTION: Hi Dan, I am installing a drop ceiling.  I have installed the wall angles on all 4 walls, what I would like to know is do I run the Tees to the edge of the wall angles or do I lay them right on the the wall angles ledge (having the angle support the end of the tee).
Thanx for any Help
Doug

ANSWER: Doug, do your room layout before you start.

I am assuming 2x4 panels.
The easiest, most simple layout:
Draw a sketch of the room, and write down the major dimensions each way.
The main concept is to have equal borders.  
E.G.: let's have the room be 20'-8" by 14'-5"

Plan on having the mains perpendicular to the joists, and draw them in your room on 4 foot centers.  There will be 10 full tiles (2' dimension) measuring 20' with a 4" border at each end. The other direction has room for 3 full tiles (4' dimension) measuring 12' with a 2'=5" left over which would make a 1'-2.5" border at each end.


Cut the main to allow the 4" border.  Position it 1'-2.5" off the wall.  Position the next one 4' more.  Yes, the mains sit on the wall angle, YOu typically pop rivet one end of the mains and one end of the cross tees NOT BOTH.  YOu are not ready to pop rivet them until you have squared the grid.  Install several cross tees in this 2 main beginning.  Start that first cross tee in the 4" hole and then each 2' until you have several rectangles established.  Use spring clamps to hold the tails.  Cut a cross tee to hold the 1'- 2.5" border and spring clamp it.  Use a string line full length of the room to establish that 1'- 2.5" dimension and cut a few more cross tees to force the mains to the line.  check the diagonals of one of your rectangles.  YOu need to get the rectangles square or installing the tile and lights will be miserable.  Move the main tails until you get the grid square, once square pop rivet in place and continue to build our ceiling grid.

---------- FOLLOW-UP ----------

QUESTION: Hi Dan, I am going nuts here, I bought Armstrong 12' tees and 2'foot tees for 2'X4' ceiling panels.  The part that I completely don't understand is that the 12" tees measure exactly 12' long BUT the slots that accept the crossing tees start about 3" in from the ends.  There are slots every 6" the problem is if I put 3 2'X4" panels that add up to my 12 foot room with the way these slots are I can't get the right configuration with the tees because the slots start 3" in on both ends with throws everything off.  
Thanx for any Help
Doug

ANSWER: Doug, you're off to a very bad start.

You need 4' cross tees.  You place one every 2'.  You will use twice as many mains doing it your way - but it will work.

Remember when I told you to make a provision for your border when you cut the main?  You will notice that the slots in the mains are every 6".  Hook the end of your tape measure in one of the slots that will allow you to make the border if the first cross tee was in the slot that you have the tape end in.  Cut the main.  The reason for the 3" space for the first slot has to do with continuing the 6" pattern as you butt the mains together - think about a WalMart ceiling.

No professional ceiling man ever thinks about starting out with full tiles at any of the walls, in fact, you avoid it like the plague as it will create giant problems when walls aren't straight and corners aren't square - rest assured, they are not.  The problems may not kill you in your small room = again think about WalMart.  In commercial work the pattern and position of the grid are driven by light locations and number of fixtures.  I doubt you planning troffer 2x4 fixtures that lay in the grid, but it explains why square and layout make so much difference.

---------- FOLLOW-UP ----------

QUESTION: Dan, it really  doesn't matter which way I run the pattern.  The fact is a 12' Tee in a 12' room won't allow you to use it as a 12' Tee!  If for sake of argument I lay the 12' Tee acrossed the room and have the ends lay on the wall angles I cannot start my 2' or even 4' cross tees until the 1st slot on the main Tee which is 3" out from the end of the 12' Tee. So after putting a 2' or 4' Tee and then a panel then another Tee etc... I will run out room before I would get to my last panel and the reason being is that the slots don't start at either side of the Tee at the very end, they start 3" IN.  This cuts a total of 6" off the usable length.  So a 12' Tee is actually only an 11' 6" Tee (Of usuable slots)on one Seperate Tee which would require an additional 6" Tee to span 12' with a 2x4 or 4X2 pattern.  I been told that the slots are 3" in from the ends so when Tees are spliced together they remain at the 6" pattern which is all well and good if you're spanning a large distance.

Answer
Doug, this will be my last response on this one.  Cut the main at any one of the slots, preferrably close to the middle.  Turn the factory ends to each other and snap them together, place the cut ends on your wall angle.

You are doing the work incorrectly, I've tried to help.  Ball's in your court.