What are all these layers in my ceiling?
Hey y’all! DIY noob here trying to replace a bathroom ceiling fan in my 1890s home. After considerable time and swearing I managed to remove the housing for the old fan and was surprised by how many layers there are up there. The walls and ceilings are always crumbly whenever I need to hang something (or more often fix something the previous owners hung incorrectly) so I’ve assumed there’s plaster… but that’s not what I expected lath to look like? It looks more like plaster, then more plaster, then concrete, then plywood, then random broken wood shims, then joists, with little tufts of broken-up insulation scattered around.
What’s going on? Is this typical? Should I replace the insulation while I’m up here? Anything I should know before widening the hole to accommodate the new fan? I bought an oscillating multi-tool and grout blade to make the cut but have never used one before. Above this is mostly finished attic space.
Thanks so much in advance. ❤️