Beware sub-zero temperatures….
Ever suffered a burst pipe? It's no fun at all – if the pipes from your water storage tanks rupture, a tank can empty itself unchecked. Even worse – if a mains pipe bursts, water can cascade down through your house until someone turns off the stopcock. If you're away, or even just at work, that may take a while…..
On the continent they tend to do it differently, but for decades here in Britain we have cheerfully adopted the practice of installing insulation above our ceilings, not to the underside of the roof. We then run our pipes above the insulation. This keeps our bedrooms nice and toasty, but leaves our water pipes out in the cold zone of our lofts. We often expose our tanks and associated pipes up high on a nice raised frame, well away from any residual heat penetrating through the ceiling into the loft. Just to flirt with danger further, we often run pipes close to the eaves, where an icy wind can whip-in through cracks and gaps.