A traditional shower enclosure makes extensive use of tiles, which are held in place by grouting, and sealed with silicone gel.
As we've already pointed out, this grouting and silicone can be a problem in itself, as both substances act as a breeding ground for unhealthy and unsightly mould.
But in a timber frame house, the problem has the potential to be much more serious.
For all its benefits as a building material, timber does tend to shift and warp over time. Homeowners are unlikely to notice this warping. But the problem is that the bathroom will warp along with the house, and shower enclosures are not designed to warp.
What do you think will happen to those solid tiles and rigid grouting as the bathroom subtly shifts around it?
They'll crack.