Overboarding artex ceiling

Hi there, Your plasterers are correct. The new plasterboard is not fixed to the lathes (the thin strips of wood) but primarily to the joists. You can always cut a section of the old ceiling out to expose the joists (you are going to be overboarding anyway) and joists are generally run evenly spaced, so one you find the first joist and know the "centres" (distance between the middle of each joist) the joists should be evenly spaced out. The alternative is to remove the old lathe and plaster ceiling, which is a much bigger and very messy job. Hi - from the added information, it sounds like metal web joists? The timber of the joists will still support the plasterboard (you could always use 9.5mm to save some weight). To find the joists you can open up a strip in the ceiling before you overboard to find where the joists are, then mark on the walls so you can see where the joists are after you put the boards up

Create a hole at the ends of the ceiling to expose joists. Do thr same in the middle and pencil line to follow the joists to screw into. Easy

Scrape back the artex, Thistle bond it & reskim done it heaps of times never fails.

If you put plasterboards over the Artex the boards will not be completely level since the uneven Artex will kick the boards out. A better solution is to scrape back the Artex as much as possible and brush the ceiling over with a PVA glue. The next step is put a coat of Bonding ( backing) plaster over the ceiling and after 20 mins flatten the ceiling as best you can. When the Bonding has started to dry ( leave for approx 30 mins ) , then plaster the ceiling using Multi Finish plaster since unlike Board Finish , Multi Finish is designed to work on all types of surfaces.