not sure about what to use

Hi there, I am not sure about something. I have a ceiling that I have brought down thanks a metallic frame and some gypsum boards. I understood that I had to leave a gap between the ceilling and the walls and that "caulking" was the term used when filling the gap. Now I am not sure, should I use a sealant such as this one:

Or can I use the same technic I would use to fill the gap between two wall boards: Thanks for the precision.

* Apply mud/plaster, as in the second picture, between the boards. * Apply sealant (kit), as in the first picture, at the outer rims where the boards meets the walls (to fill that 1/4" (about 6mm) gap) The stopgap, from Auralex, is expensive but good for the job. You might wanna shop around (if money's an issue) for a sealant kit with following properties: - Permanent flexible (will not dry and harden) - More mass than average - Will not shrink (- Will attach to gypsym, wood, etc.) Those are the things to look for concerning sealant (picture one)

much better pict yeah ! The only distributor of auralex in France does not do this product (stopgap). But I found a site in the US agreeing to deliver in France. The only thing is how many tube do I need ? The tube is $19.95 and they say it does 89 lin ft. about 27 meters. I thought that was a bit exaggerative but hey I have never used it so. Anyone with the experience of stopgap can confirm that ? Thanks Alex

ah ah, one thing I did not think about is that these tubes are large tubes not like the one we have here in Europe. So I understand now why it can cover such a long distance. But then I would need a gun for it :(... not available in France, starting to be frustrating....

That "large" gun can be purchased at the same compagny that sells them tubes, most of the times. Also, ANY Auralex can (should) supply stopgap imo.

Thanks Ro for your presence. A last thing, what is Foam Baker's Rod, the thing I also need to put right before caulking ? Is that necessary ?

Backer Rod is a material you have/can use prior to sealing. Just google with images onnit to have a clue. Comes in rolls, looks like a tube. I remember DAN having some pictures and extra info in his thread. Also you might wanna check the stickies, there's a mention and weblink somewhere. (this one for ex. http://www.loghelp.com/backerod.html) It's used to prevent you from using to much seal. check http://www.albioneng.com/index.asp for info about backer rod, sealing kit, methods etc. to give you a clue.