build on top of existing extension

Hi if I was honest , the whole job would be a lot easier if you take the ceiling down. If you protected the units and sink/ work tops correctly you could take the ceiling down quiet easily . So no in my option through previous experience yes take the ceiling down. But make sure you cover the kitchen and your answer would be no you don't have to replace the kitchen , because you have taken the correct procedure . Thanks lee

As the kitchen ceiling plasterboard must be attached to the new floor joists you are planning on installing it cannot be in place during construction. Firstly, there would be nothing to support the ceiling plasterboard after you had removed the structure above it. Secondly, if you did support the plasterboard from below all of the work would move the plasterboard slightly thereby cracking it in many places, necessitating many tricky repairs. Personally, I would treat the ceiling as part of the necessary renovations and either protect the kitchen below with heavy plastic, or if you wanted to use the kitchen during the weeks of construction create a temporary false ceiling a few inches below the existing plasterboard, having first removed it.

You do not need to take the existing ceiling down at all! When building above, you would pack up the new wall plate or you would have to use oversized timbers to act as new floor members so the new floor joists are independent of the ceiling joists. With the extra height, you can still put noggins between to strengthen new floor. The only reason you would have to disturb the old ceiling would be if you needed to cut out access for new stairs. Hope this helps

Hello. Unfortunately disruption is inevitable; your current ceiling joists will be sat on a timber wall plate. It's not good practice to build on timber therefore this would be removed which will mean the ceiling and ceiling joists will need removing. I'd recommend removing the kitching prior to works Regards Dale Steel