SOLAR WATER HEATING - BETWEEN THE ROOF FRAMES

Go into the loft and measure imbetween the roof frames, saw the wood off as accurately as possible to ensure a tight fit imbetween the frames to secure the solar water heater securely, I tend to use a snip saw to get an good finish.
Put wood glue on each end of the wood the gently tap the wood up imbetween the roof frames, you may need a small hammer at this point. Get a five millimetre drill bit and drill two holes through the roof frames and into the end of the piece of wood and screw to secure the wood into position