If you have a roof leak it may well be through the valley. This is where two parts of the roof join. This video shows the full repair from removing leaded valleys and replacing with new plastic ones! I promised a follow up review on the gunk that I used in the first place, but it didn't work for long as the valleys really needed renewing http://youtu.be/LrVNmdrgKjo My new website on DIY ,household repairs ,plumbing and heating is at: http://www.dereton33.co.uk
