Correct way to attach drywall between floor joists

Hi, I am beefing up the ceiling of one of my life rooms and it involves putting 1/2" drywall between the joists, cut to size. The floor above these joists is 1/2" OSB sheets. The job has to be done from underneath ( I cannot lift the OSB sheets to be able work from above) Question Is there any problem attaching the drywall to the OSB between the joists with drywall screws leaving a perimiter gap and then chaulking? How best to attach the second and 3rd layers between joists... Thanks hally

Hi You don't live in Cork do you? Was the original construction plumb? Or will you have to measure and cut every section? The closer fit the better I would think, plus plaster board is cheaper than acoustis chaulk

Hi lilith_envy , No I don't live in Cork, I am living near to Dublin...I have to measure and cut every section, the original workmanship on the building was terrible, joists are not on centres, same for the rafters. I have the 1st layer of plasterboard up and sealed with chaulk, question, what is the suggested way to attach the second layer and possibly a 3rd layer? Cheers hally

Bill Shoup has a basement build and did some overhead mass add. viewtopic.php?t=9343 You can use small finish nails to support the plasterboard in place. While adding the pieces you would drive the small nails into the joists under the piece, as a means to hold the plasterboard in place. If this isn't working then you may need short temporary wooden strips that you can screw into the joists directly underneath the plasterboard while you build up your layers. Maybe 12 inch (30 cm) pieces of 1X2 that you can install to overlap at the joint area. This would allow you to continue your install and add and remove the temporary wood strips until you are completed. Then install a final full piece to support the entire thing. Certainly the extra load on the joists is to be taken into consideration. This can be more of a load then your overhead joists are expected to support. Especially when you add the impact of the human body and/or dead loads of furniture, appliances, etc. Good luck