I continued taking down the walls of the downstairs bathroom, which you can see a little more clearly in the photo below. The room was built over with a new extension some time in the '90s (guessing based on newspaper found in the woodwork), and the roof of the new extension has failed.
When the ceiling eventually came down it revealed a bit of a major problem. It transpires that the new extension is a bit of a bodge-job (suprise, suprise) and that the four beams which cross the span above the old bathroom are sat on a piece of wood that isn't fixed to the building in any way. The whole corner was just sat on the very old, slightly crumbly beam which was holding up the ceiling of the bathroom.
Unfortunately, as the ceiling came down, that old beam shifted (see below, it's being held up by a strut) and the entire new roof sagged downwards.
It's difficult to make out in the picture below, but the old beam (painted white) isn't fixed to the wall. And the new beam which is sat on top of it (you can just make out the pine-coloured end, which has sagged about 4-inches) isn't either.
A little clearer in this photo perhaps, the old beam (white end) is holding up a new beam, on to which the roof struts sit.
A bit of a panic later, as I stood underneath the unsupported roof, and I managed to use a bottle jack and ad-libbed wooden strut to gently lift the beams back in to their original position and hold them there.
The bathroom ceiling, which I'm assuming is as old as the brick part of the house (1880-ish) is a lath and lime-plaster construction, and really interestingly it's made from rough-cut branches rather than sawn or planed beams. You can clearly see the bark and knots still on the old struts.
When the dust cleared and I was happy with the support which is now holding up the Sun Room roof, I took a moment to have a look at what was revealed.
There's a peculiar archway construction between the WC and the Kitchen, which we know used to be a doorway. I had until now assumed that someone had knocked this archway out at a later date than the house was built, but a closer look suggests that it was originally built this way.
You can just about make out that the brickwork itself is arched (middle of the photo below).
I wonder if originally the WC was some sort of built-in larder or pantry.