Conservatory leaks but not from conservatory roof??

[Budman]

Hi there. I hope you can help with this head scratcher.
My lean to conservatory has been leaking for several winters now but only in high winds and heavy rain, which in Scotland can be pretty regular these months.
The leaks appear in 2 places, on the wall where the conservatory joins the house. One leak runs down the window that looks from the kitchen into the conservatory (on the conservatory side) and the other from the door into the conservatory from the house.
I assumed the leaks were from the lead flashings since its an old conservatory. I've had 3 roofers out over the years, all agree that the flashings look fine but pumped gallons of sealant into any crevice they could find. The last roofer (who's boss is my wife's step father so I completely trust) spent a day completely waterproofing the flashings and any gaps just to be sure, though agreed prior to this that the flashings looked ok to begin with.

That was in the summer and I had high hopes however now we've had the first heavy wind and rain of the winter...the leaks are back, heavier than ever and I've the bucket and towels back out! I'm at my wits end and a loss as to the location of the water ingress.
I'm wondering now if it's possible for the rain to be pushed in further up the wall ie. the bedroom windows or the roof of the house?
Could water get into the cavity walls from here and make its way down into the conservatory?
Any help would be appreciated. I'm at a loss as to what tradesman I'd even get in now!
Thanks

 

[theprinceofdarkness]

As both "leaks" seem to be associated with openings in the outside skin of your house wall, I reckon that penetrating rain is running down the inside of your house wall cavity until it hits the lintel, then piles up and drips out (the wrong side). Before the conservatory was built, this area would have been wet with the rain, so a few more drips could not have been seen. To test for this just turn a hose on the wall above where the leaks are/ Might take longer then you think to soak the wall. To cure it, either waterproof the upper wall, or re-engineer the flashing so it penetrates into the cavity with a "hook" top to it, so water it catches drips out over the top of it. As you have a real active problem, I would try a bodge first, could work and its 100 times faster then the real cure. That is find out where the leak is and remove the pointing and mortar against the flashing. say givng a little slot 1/2" long, use a piece of wire and a vacuum cleaner to make sure that the top surface of the flashing is a little lower then the internal pointing level, to encourage the water to come out of your new hole. Do a sketch to get your levels.
On modern builds, there are "proper" leak holes but they are associated with cavity trays that capture this unwanted water.
Frank