Downpipe over roof

[jambojambo]

Hello,

My dad is concerned about a suspected leaky roof. The photo attached shows the roof, with downpipe running water from above onto it.

Should the water from the roof above be allowed to run across that roof? Or should the downpipe at left be be made to connect directly to the gutter (bottom right of picture).

incidentally the leak only happens when they get rain and wind heading straight to that roof (i.e. from right to left of the picture).

Many thanks, Jamie

 

[oldbutnotdead]

It's never a good idea to have that sort of arrangement, especially on a shallow pitch. Your leak though sounds more like insufficient overlap on the tiles (assuming you mean when the wind hits the roof square on).

Easy fix is stick a length of pipe on to the fallpipe and get it to drop into the gutter (difficult bit is securing the pipe to anything- if you don't secure it it will rattle in the wind. You might have to divert the fallpipe off the side of the roof then along the gable wall and intercept the gutter downpipe). Try doing the pipe direct anyway and see what happens (the next time the wind blows in that direction). While you're up there, have a measure of the tiles, see how long they are and by how much they're overlapping

 

[^woody^]

On the basis that roofs are 'waterproof', its not a problem.

Its actually not a problem in thousands of properties up and down the land, and much better than a hideous piece of pipe running down the roof, IMO.

If there is a roof leak then the roof is defective and that is distinct from the drainpipe arrangement.

 

[oldbutnotdead]

On the basis that roofs are 'waterproof', its not a problem.

Its actually not a problem in thousands of properties up and down the land, and much better than a hideous piece of pipe running down the roof, IMO.

If there is a roof leak then the roof is defective and that is distinct from the drainpipe arrangement.

True- the pipe solution is fugly but a temporary drop can at least quickly and cheaply eliminate it from the possible causes of the leak (which I still reckon is insufficient overlap)

 

[catlad]

Well in an ideal world the down pipe would not be put there in the first place, and
I would put money on it not leaking if you divert the water over the side of the roof.

 

[^woody^]

No water should be getting through that roof wherever or whatever direction the rain water is coming from.

 

[theprinceofdarkness]

Lead flashing should only be laid in up to 1.5m strips, else the expansion/contraction buckles it (from the lead assoc. website) it should have hooked joints. Also I wonder about the amount of tile under the lead, and what is under the lead at the very top.
Frank

 

[wessex101]

Those large flat profile concrete tiles are notorious for the side laps leaking if there is excessive rainwater run off, manufacturers recommend not using on long roof spans because of this. I suspect the rainwater downpipe is flooding the tiles and with the combined wind and driving rain is overwhelming the tile lap joints.

My vote is to re-route the downpipe or at least try the temporary pipe extension as suggested above to see if that fixes it.

 

[jambojambo]

Brilliant. Thanks all. Going to try the temporary fix to see if it changes anything rather than do anything drastic now.

 

[noseall]

I agree with Woody in that a crap roof will always be a crap roof regardless of that DP arrangement.

My money is on a pants lead detail under the sill in that it has been cobbled up rather than done properly. Other than that, it is difficult to determine a leak when it only occurs during specific weather conditions. The felt must be crap too.