3.5. Inadequate fixing of tiles, accessories and hip tiles. The method of fixing of tiles at abutments relies on a combination of self weight and in some cases gluing !) the tile to the underlayment with silicone (see Roof Inspection Report, page 18). The absence of battens to support the uppermost layer of tiles means this tiles sit on a different angle to the tiles below and open a gap which allows penetration of wind driven rain.