Shared roof - Valley water Problem!

[chris101]

Over 1.5 years back we had a side extension of our house. The neighbours had done the same side extension a few years back and was a little over the boundry line however as the neighbour agreed for us to share the wall, the builders built a slanted tiled room which drained water into a shared lead valley.

The problem is as follows -

This shared lead valley is used from both main roofs and the water only flows into a standard sized guttering box which is on my side of the roof.

This gutter continuously gets clogged with gung and the gutter over flows with water causing our internal wall to damp and paint to come off.

The builder has been back a few times and tried to put lead on one side of the gutter but when it rains hard it still over flows.

The builder says this is the best he can do and we need to simply regularly clean the gutter but at the moment, it seems regardless if we clean it on a daily basis, if it rains heavy it will still over flow and get blocked up.

The builder seems to be running out of ideas....
Any suggestions what we can do? We cannot have the water over flowing into the garden each time it rains and the bigger issue is the damping onto our internal wall.

Another issue is the the new slabs on the patio are already uneven and there is movement on some when you step on them.
I have flagged this up with the builder and he said as our house is an old 1980's house, movement is to be expected and there is no way round this apart from each time re-cementing it.
He has also advised the same applies to the cement falling off the walls e.g. the patio joins onto the back extension....

Is this true or am I being fobbed off?

 

[ree]

Perhaps some pics would help?

 

[chris101]

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Sorry these were taken when works were being carried out.
I will attempt to take some during the day tomorrow to give you the bigger picture of the different areas water is draining into/from.

 

[catlad]

It looks like you need a roofer not a builder, yes he is fobbing you off.

 

[ree]

1. The "valley"lead that discharges into a hopper head seems to be a little shy of a fully developed lead chute. Detailed pic needed.
Do you have the width and depth dimensions of the valley?
Does the valley have lead expansion joint pieces or is it one long strip?

2. Does the neighbour's black plastic gutter discharge into the hopper head?
The h/h and down pipe are leaning - angle fittings could rectify that.

3. The valley appears to have a very shallow fall which means its not self cleansing.

4. There also appears to be a variety of down pipes (and waste pipes?) that could be discharging into the valley from various roof planes above, unless there is a higher gutter on the neighbour's side?

5. where are the main down pipes for both properties?

FWIW: how did you go on with your previous rat difficulties?

 

[chris101]

1. The "valley"lead that discharges into a hopper head seems to be a little shy of a fully developed lead chute. Detailed pic needed.
Do you have the width and depth dimensions of the valley?
Does the valley have lead expansion joint pieces or is it one long strip?

2. Does the neighbour's black plastic gutter discharge into the hopper head?
The h/h and down pipe are leaning - angle fittings could rectify that.

3. The valley appears to have a very shallow fall which means its not self cleansing.

4. There also appears to be a variety of down pipes (and waste pipes?) that could be discharging into the valley from various roof planes above, unless there is a higher gutter on the neighbour's side?

5. where are the main down pipes for both properties?

FWIW: how did you go on with your previous rat difficulties?

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Please see the pictures to answer some of your questions.

I do not know the dimensions for the valley although I believe it is one strip.

The angle has been slightly rectified although the issue with blockage is more to do with the trees and gung that keeps gathering up.

 

[ree]

Pic 5. and pic 6. the piece of lead off-cut, creating a chute of sorts, doesn't need to go all the way into the hopper head - its creating a narrow funnel blockage, and must be cut back or re-arranged.

A lead working roofer will be needed to sort out the whole of that discharge area. Essentially, the valley lead should have been continued another 200mm, and then worked and dressed to suit. The black plastic gutter was left too long.

The felt on the neighbour's side is going behind the lead valley and possibly weeping on to the valley board. The felt on your side is stopped short of the lead (see pic 5.) so the same thing could be happening.

In pics 8. & 9. the neighbour's roof changes plane and kicks up (just where it changes into a hip roof, directly in line with the hopper). This could be allowing moisture entry below the tile to run down the felt - which can be seen in pic 5. to be damp.

Pic 7. is the H/Head leaking as it sits incorrectly on the down pipe? Anytime pipework is strained it will eventually leak.

If the valley gutter is one piece of sheet lead then it will inevitably crack in a number of places due to expansion and contraction. Sheet lead expansion joints can be retrofitted by a lead working roofer. It would be disruptive to do in that narrow valley.

The valley dimensions appear to be very adequate.

 

[chris101]

Sorry should of stated, the builder recently (2 weeks back) put the cut out of lead there to stop the water over flowing onto the wall.

Pic 7 - Although incorrectly seated, it is not leaking.

Any recommendation where I might be able to find a lead roofer who knows what he is doing?

 

[catlad]

Anyone who builds something like that and does not move the top water away from a potentially problematic area is very foolish, You might find if you re-align the gutters on both sides so they no longer discharge into that valley then that could be the end of your problems.