With such importance, it is necessary any installed measures are adequate and cover the anticipated areas.
Loft insulations should always extend TO the eaves but, NOT IN them because the roof space needs to be well ventilated to stop condensation damaging the structural timbers. Even though a loft is insulated, warm air will still permeate through the ceiling into the loft area hence, this warm air MUST be able to ventilate to the exterior.
Inadequate cover is a common fault whereby the gaps lead to those mouldy black ceiling areas close the walls. What is occurring is that this area remains colder than the surrounding well-insulated area that will attract warm moist air when the room is in use. Naturally these two elements coming into contact with each other will lead to condensation and the inevitable mould.
Wall cavity insulations are designed to store the heat within the inner walls, bouncing it back into the room and holding it for longer. This is expected to give you a more even temperature and gets rid of the draughts that come down from the walls.
Installations in the UK should always consider the property age, style and geographical location before having it installed. Why? Because inappropriate installations can, and do, have adverse effects on the structure and ultimately the expected interior condition. Most problems have been claimed to occur in houses which were built prior to the 1980s that originally had clear cavities now filled with the known common culprit being blown mineral-wool fibre.
This material consists of loose fibres blown in through holes drilled in the brick outer leaf. It has been claimed the material is water-repellent however, research has shown this material can readily soak up water. And, when this material is wet it loses its thermal capability resulting in actually making the ‘insulated’ wall colder. Hence, complaints have been made suggesting their homes are now colder than they were prior to the installation.
Another consideration is the geographical location of the dwelling because south facing elevations experience a warming effect particularly during the summer periods that will warm the cavity area. Subsequently during the nigh periods the wall is cooled but, the warm cavity can, and does, start to condensate. With daily changes in temperatures, these elevations are prone and indeed have suffered significant damage including a full collapse due to subsequent rotten wall ties.