In PART ONE of Before Installing Solar PV Panels, a number of basic issues, which are not always obvious, were pointed out, and to which a competent solar PV installer should address when assessing a household rooftop before commencing work. It cannot be stated too often that as the solar PV industry grows and domestic demand rises, it's vitally important that properly trained and qualified solar PV installers should become the backbone of the industry.By letting the inevitable 'cowboy' element gain a widespread foothold, serious damage can be done not only to a household roof and the occupants, but also to local area energy development and genuine, professional solar industry installers. The long term strategy is to shift the UK from dependence on fossil fuels to renewable energy sources and reduce CO2 emissions within the coming decade. It is, therefore, too important to be allowed to be undermined by those rogue trader individuals intent only on pocketing an easy day's pay from unwitting victims sold an inadequate system, incorrectly installed .The actual physical mechanics of attaching a solar panel system to a rooftop needs to be clearly understood. From the point of view of the roof itself! An incorrectly attached system can and will destroy the integrity of a perfectly serviceable roofing structure. If, as is mostly the case, panels are fitted in the dry summer months, any weaknesses created by, for example, penetration of the insulation and waterproofing, or slight structural alterations affecting accommodation of seasonal temperature changes, will not become apparent until the winter months, when leakage, or worse, occurs.A key issue is the roof material itself. Simply stated, there are some roofing sheets, such as fibre-based or much older asbestos-containing roof sheeting, that are not load-bearing rated, whatsoever. Asbestos-cement based materials, especially, are dangerous if their fibres are disturbed in any way and released into the air. Cement-based roofs must be allowed to 'breathe' and release condensation. No attempt must be made to attach any object on to the surface or even secure fixings, which?