Simulated slate roof leak but why?

[T5TDI]

I'm hoping someone could help me with this because I certainly don't know much about roofs! As far as I know the roof is around 15-20 years old. It has underfelt which looks in good condition as do the slates which have hooks in each one to battle the wind driven rain here in sunny Cornwall.

It all looks good to me but yet it is leaking 12 inches or so up from the eaves and running down a rafter on to the supporting wall and into the room below.

Other than having it all stripped off are there any common things with these fake slates I could look out for? I could try posting a picture tomorrow if you think it would help. Thanks!

 

[datarebal]

By fake slate do you mean cement fibre slate?
these would not require hook fixing anywhere.
it might be you mean cdr.. (copper disc rivets) which would show at the bottom of the slate.

Cement fibre slates, provided they are laid correctly should not be a problem.

if you have some other slate .say a brizillian which should be hook fixed then it is highly likely there are a broken slate or two . The damaged section will be held in place by the hooks.

A picture will help.

 

[T5TDI]

Thanks for your reply! I got hold of the original 1959 plans for this house and it shows the original roof as wooden shingles! The neighbours agree it was like that once but has been replaced with these slates or whatever they are. The chimney doesn't look too good either....

Ignore the scaffold poles holding down a tarpaulin on the leaking flat roof below the leaking main roof!

 

[ladylola]

It's a little unclear from the photos but I think that the chimney could be the source of your leak. I can't quite see how the flashing is but the chimney is on a line with you leak , it's possible water is entering at the chimney and running down the felt to where it finds a tear or hole a foot or so from the bottom and is entering the building there. The fixing on the face of the slate in your photos shouldn't be letting in water unless it's been done wrong .

 

[Alastairreid]

Filling between the slates in your last pic will do more harm than good!

chimneyhead does look suspect, though the flat roof and gutter looks even more so.

 

[T5TDI]

We originally thought the flat roof was the culprit too but found water dripping higher up when crawling around in the loft. By that time we had already put the tarp on the flat roof. We tucked the tarp under the bottom row of tiles and added the silicone because we may have to leave the house while other work is done (don't ask!) and it won't stay there if we have one of our gales (hence the scaffold poles) This flat roof is due to be replaced next year anyway when we convert the garage to a bedroom.

I never thought of the chimney causing it because it is so much higher, but it must be almost dead in line with the leak! Knowing this house the chimney won't have any flashing at all. Until I have time to get it all re-done properly in the spring it's going to have to be bodged with more tubes of silcone.

Thanks for your replies. You have been a great help.

 

[T5TDI]

We originally thought the flat roof was the culprit too but found water dripping higher up when crawling around in the loft. By that time we had already put the tarp on the flat roof. We tucked the tarp under the bottom row of tiles and added the silicone because we may have to leave the house while other work is done (don't ask!) and it won't stay there if we have one of our gales (hence the scaffold poles) This flat roof is due to be replaced next year anyway when we convert the garage to a bedroom.

I never thought of the chimney causing it because it is so much higher, but you're right it must be almost dead in line with the leak! Knowing this house the chimney won't have any flashing at all. Until I have time to get it all re-done properly in the spring it's going to have to be bodged with more tubes of silcone.

Thanks for all your replies. You have been a great help.

 

[T5TDI]

Sorry for the double post. Can anyone guess from the pictures what my slates might be made of? They look like some kind of lightweight slate copy but they have weathered some pretty big storms here on the North Cornish coast so I suppose they must be ok...

 

[Alastairreid]

http://www.marleyeternit.co.uk/Roofing/Slates.aspx

View media item 28169

 

[T5TDI]

Aha! Thanks for that alastair.

 

[datarebal]

they are cement fibre,probably eternit i woudl guess

 

[T5TDI]

I've just realized I never updated this thread. Although we had the chimney rebuilt (some of it was literally falling apart) the leak persisted.

In the end the problem was that the underfelt was split where we couldn't see it above the original cavity wall (the roof must have been extended at some time to cover the bathroom extension) plus a few cracked slates.

Most of the water had been going into the cavity and the rest down the bathroom wall!

Thanks to everyone for your help.