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- 10 Oct 2008
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Had a roofer in about six years ago to rebatten and refelt (breathable type) the entire bungalow roof.
There are six valleys that were originally of the lead type which were all replaced using Klober dry valley troughs (KR966100).
At first all was OK but recently during a short intense downpour, I was getting a fair bit of water going through the roof.
I have since been on the roof myself and found the following.
The GRP gulleys were fitted without the underside counter battens and it looks as though over time the weight of the tiles has squashed the section reducing water flow. I also noticed that nails were used in the trough section which were coated with some tar like material which has mainly been washed away now.
To my surprise the valley boards were not at the same height as the top of the joists, instead 25mm boards were layed on top of the rafters and the trough was layed minus any counter battens on top of this. The outer edges were simply nailed down to the battons. Also one valley board is about 6mm higher than the other for some reason.
I have now removed one valley completely and done some experimentation with what I have as follows.
I have added the missing counters batten (one each side and two in the middle) which has now restored the gully section to its correct height BUT as expected it is now about 25mm higher than it should be. I have Redland Regant tiles and with some difficulty I am able to pull them onto the GRP valley to reach its centre position. The fit is very tight.
Would this be a suitable solution to the problem or would this just cause further trouble in the future?
There is another option and that would be to completely rework the valley board so that it fits at rafter height but this would require removal of some of the ridge tiles which are currently cemented into place.
Any help or recommendations would be appreciated.
Regards
Farmer Jo
There are six valleys that were originally of the lead type which were all replaced using Klober dry valley troughs (KR966100).
At first all was OK but recently during a short intense downpour, I was getting a fair bit of water going through the roof.
I have since been on the roof myself and found the following.
The GRP gulleys were fitted without the underside counter battens and it looks as though over time the weight of the tiles has squashed the section reducing water flow. I also noticed that nails were used in the trough section which were coated with some tar like material which has mainly been washed away now.
To my surprise the valley boards were not at the same height as the top of the joists, instead 25mm boards were layed on top of the rafters and the trough was layed minus any counter battens on top of this. The outer edges were simply nailed down to the battons. Also one valley board is about 6mm higher than the other for some reason.
I have now removed one valley completely and done some experimentation with what I have as follows.
I have added the missing counters batten (one each side and two in the middle) which has now restored the gully section to its correct height BUT as expected it is now about 25mm higher than it should be. I have Redland Regant tiles and with some difficulty I am able to pull them onto the GRP valley to reach its centre position. The fit is very tight.
Would this be a suitable solution to the problem or would this just cause further trouble in the future?
There is another option and that would be to completely rework the valley board so that it fits at rafter height but this would require removal of some of the ridge tiles which are currently cemented into place.
Any help or recommendations would be appreciated.
Regards
Farmer Jo
