Question about tiling the bathroom now -

[TheMadMonk]

2. Shouldn't to any great degree, but of course much would depend...

...on you not dropping a hammer through the ceiling, or being too violent with the common wall.

From your description this is currently an external wall, which may well mean the nails fastening the siding could well and truly be rusted in place. Unless that siding is willing to come away easily, your best bet may be to batten OVER the boards then fasten your wall material to the battens. Use screws rather than nails.

Couple of useful bathroom/general renovation tips.

- Vaseline will prevent silicone sealants from sticking to glass/tile. Clean up only after the sealant has fully set.
- Use masking tape when running long beads of silicone. Lift it before the sealant sets.
- Fingertips cut from kitchen gloves will help prevent blisters while grouting tiles.
- Always ensure that there is a small gap anywhere drywall meets a horizontal surface. This one applies EVERYWHERE.