Leaking Roof

[Quillan]

Yep I have one and I have had it for a while.

It leaks obviously when it rains but not all the time i.e. it depends on how much i.e. the ferocity of the rain. It's raining at the moment and there is no leak, a moderate amount but when it rains harder it leaks. Last year, yes it has been going on a while, having visited the roof looking for holes, slipped tiles etc I pulled the whole ceiling down to see where it was coming in and then looked directly above the leak. Everything looked OK as I said, no slipped tiles etc.

Now I have realised that because the tiles are sitting on chipboard the leak through the tiles could be anywhere if the roof is not level (left to right) and run down either directly or at an angle to the first place it could get through the chipboard. I have looked over a large area of the roof and all the tiles are OK. I did reseat a ridge tile using cement and then painting the joint ith that redish silicon rubber stuff roofers use here and it still leaks. I really am now worried that the whole roof will have to come off and be replaced all because of a small leak that only happens when it rains hard. Any ideas?

[Théière]

Best to remove and replace but if that's not possible a local repair around the affected area but using a water proof breather membrane to prevent the leak.

[Quillan]

Probably but the house was built in 1987 and the tiles are reasonably modern i.e. they look like a semi circle with a plate off to one side which forms the valley (?) and the next tile to the side locks into.

[mint]

Do you mean half-roman tiles, Q?

You really need to examine where the water comes in.

For example, when there is wind, water often blows in under the ridge tiles and gets into the building.  Can you see where the staining is?  Post a picture to give us a better idea?

Also, what location is under the leak?  Not around a chimney stack, for example?  What is beneath the leak?

[dave21478]

Mine leaks in heavy rain due to the flashing around a chimney not being high enough. Normal rain is ok, but a very heavy deluge means water builds up against the chimney and seeps down the back of the flashing.

You will probably have a similar problem somewhere, where either wind direction or water quantity is the issue.

[Chancer]

It sounds like you have been looking for the leak from the Inside having pulled down a ceiling to do so, rather extreme to avoid getting up a ladder.

You probably just have a cracked tile or a leaking flashing , you are right to be looking further above but do it from the outside.

Sometimes a phto taken at high res and then enlarged may show you the problem if its a slipped or damaged tile but not a cracked one.

I recently resolved a leak that I have had for a couple of décades, it was only once every few years in a major storm with the Wind in a certain direction, I thought it was blowing Under the tiles and my problem was old torn roofing felt, it turned out to be a cracked tile.

Its rare to find a roof leak by looking from the Inside unless you have no roofing felt and can see the underside of the battens and tiles.

[Théière]

Its the sitting on chipboard part I find amazing.

[Quillan]

Ok a couple of questions there to answer.

Chimney, on the opposite side of the roof so thats not an issue unless water can run up hill for quite a distance.

I don't know what a Roman Tile is. I looked on the internet this morning and found the following photo which is almost (99%) identical to mine.

http://www.traditec.com/images/stories/food/new_rooftiles/Woestelandt%20modellen/Belgian%20Tempest%20tile%20natural%20red(small).jpg

Taking a photo is a bit difficult as it has not stopped raining yet but we have no leak with this level of rain.

Accessing the roof is not an issue as it can be done from a window straight onto the roof. There are three vertical levels of roof involved each one a metre higher than the next. So walking on the roof and examining it is not a massive problem.

Somebody said moss in the joints which could cause capillary problems?

I took the ceiling down because it was lambris and I saw it as an opportunity to find the leak at the same time. The leak has always been roughly in the same place on the inside and I have looked directly higher up the roof from where it comes through on the inside thinking the water may get through higher up then run down the ceiling looking for a place to exit.

 

[Quillan]

[quote user="Théière"]Its the sitting on chipboard part I find amazing.[/quote]

Round here they seem to sheet the roofs with chipboard, put battens on then tile. I would have expected to see a membrane of some sort on the chipboard first, then the battens and finally the tiles. I have watched them replace and also construct new roofs using this 'no mebrane' method many times round here over the years. The only person I know who has used a membrane is an English friend who built his own house.

[nomoss]

[quote user="Quillan"]

[quote user="Théière"]Its the sitting on chipboard part I find amazing.[/quote]

Round here they seem to sheet the roofs with chipboard, put battens on then tile. I would have expected to see a membrane of some sort on the chipboard first, then the battens and finally the tiles. I have watched them replace and also construct new roofs using this 'no mebrane' method many times round here over the years. The only person I know who has used a membrane is an English friend who built his own house.

[/quote]

Our builder (French), not far from Carcassonne, uses 13mm OSB over the rafters, followed by a textile membrane. This is followed by vertical battens, to allow any water ingress to drain, then horizontal battens to take the "mechanical" canal tiles.

[Théière]

Some cheap sarking board idea by the sound of it which obviously works well until it rots away, more of a no brain way as everyone else uses membrane. the membrane is not pulled tight so as to form gulleys that direct the water down to guttering.

When/if it stops raining you may need to climb up with a hose and start spraying around carefully to try and make it leak. Moss sounds unlikely as it will form between the joins but they overlap.

I do hate roofs and tiles such an old idea and we still use them today when we could do better.

[nomoss]

[quote user="Théière"]Some cheap sarking board idea by the sound of it which obviously works well until it rots away, more of a no brain way as everyone else uses membrane. the membrane is not pulled tight so as to form gulleys that direct the water down to guttering.

[/quote]

I have seen many recently built roofs in this area, and they have all used OSB, which is waterproof, over the rafters, not chipboard, which is not.

[mint]

[quote user="Quillan"]

Accessing the roof is not an issue as it can be done from a window straight onto the roof. There are three vertical levels of roof involved each one a metre higher than the next. So walking on the roof and examining it is not a massive problem.

[/quote]

So, are there walls abutting the different levels of roofs?

If the answer is yes, what sort of flashing do you have between the wall of one part of the building (higher part) and the lower roof of the abutting part of the building ?  I hope that, if the situation is like this, then you have better than bits of crumbling mortar fillets so seemingly favoured in many houses! 

[Théière]

Hence my point.

[Quillan]

[quote user="mint"][quote user="Quillan"]

Accessing the roof is not an issue as it can be done from a window straight onto the roof. There are three vertical levels of roof involved each one a metre higher than the next. So walking on the roof and examining it is not a massive problem.

[/quote]

So, are there walls abutting the different levels of roofs?

If the answer is yes, what sort of flashing do you have between the wall of one part of the building (higher part) and the lower roof of the abutting part of the building ?  I hope that, if the situation is like this, then you have better than bits of crumbling mortar fillets so seemingly favoured in many houses! 
[/quote]

The tiles appear to be cemented into the walls and then the crepie was applied which I can tell you is nearly 10mm thick. I have examined along the joints but can't see anything that jumps out at me.

[Quillan]

[quote user="nomoss"][quote user="Théière"]Some cheap sarking board idea by the sound of it which obviously works well until it rots away, more of a no brain way as everyone else uses membrane. the membrane is not pulled tight so as to form gulleys that direct the water down to guttering.

[/quote]

I have seen many recently built roofs in this area, and they have all used OSB, which is waterproof, over the rafters, not chipboard, which is not.

[/quote]

To be fair I use the word chipboard because that to me is what ith loks like but it is green (bit faded now) which I thought ment it was waterproof?

I seem to remember somebody calling the tile 'mechnic' or simular but they do look like the ones in the photo link I gave.

[Théière]

[quote user="Quillan"]

To be fair I use the word chipboard because that to me is what ith loks like but it is green (bit faded now) which I thought ment it was waterproof?

[/quote]

The fact you are posting would suggest not [;-)] P5 as we know it is pretty good but any cut edges or damaged surface are just as vulnerable as normal chip, OSB uses a resin glue which is better but again a cut edged is compromising the board.

[ventodue]

[quote user="Quillan"] Now I have realised that (because the tiles are sitting on chipboard) the leak through the tiles could be anywhere .. <snip> [/quote]

A very wise observation!  Just be aware that chasing the source of minor leaks can be a deeply, deeply frustrating pass time [:'(], with the point of entry often being a considerable distance away from the eventual point of exit.  In small quantities, water can track a surprisingly long way across a horizontal surface before eventually reaching a barrier which, altho' almost imperciptible, is just enuf to make it start to drip, drip, drip ...

That said, and as other have advised, do cast a very suspicious eye on all your flashings and cement joints.  If the leak only occurs in heavy rain, they, IME, are a more likely culprit than a cracked tile.

[quote user="Quillan"]  I really am now worried that the whole roof will have to come off and be replaced all because of a small leak that only happens when it rains hard. [/quote]

No, won't come to that .. honest![:-))]

[mint]

[quote user="Quillan"][quote user="mint"][quote user="Quillan"]

Accessing the roof is not an issue as it can be done from a window straight onto the roof. There are three vertical levels of roof involved each one a metre higher than the next. So walking on the roof and examining it is not a massive problem.

[/quote]

So, are there walls abutting the different levels of roofs?

If the answer is yes, what sort of flashing do you have between the wall of one part of the building (higher part) and the lower roof of the abutting part of the building ?  I hope that, if the situation is like this, then you have better than bits of crumbling mortar fillets so seemingly favoured in many houses! 

[/quote]

The tiles appear to be cemented into the walls and then the crepie was applied which I can tell you is nearly 10mm thick. I have examined along the joints but can't see anything that jumps out at me.

[/quote]

Ah, you mean blotting-paper then?

Have you never observed large areas of very damp crepie after heavy rain or observed those red, rusty looking stains on crepie where the colour of the red blocks (whatever they are called) have leached out?

Also, what about crepie that have sheered off walls after water entry where the water has frozen and then melted?

If you do have walls higher than abutting roof planes, then that is a VERY likely source of water entry.  The solution can be complicated involving disc-cutting and application of flashing in special ways to induce the water to run away from the building.

Not so effective but may serve is if you paint the higher abutting wall with something like masonry paint but you will need to do it repeatedly.

If you CAN manage it, Q, post a photo where you think the problem might be.  It'll be easier to diagnose it then.

PS I believe your tiles are called "single roman" but I don't know what they are called in France.

[Théière]

Who wrote what? I am confused.........

[Quillan]

Mint - Our house is built with concreate blocks on the outside, screeded then crepie applied. Cavity wall with insulation then the red bricks on the inside but only one 'hole' deep which I think makes the 50mm brick.

[BIG MAC]

Have you considered carefully drilling the sarking board in roughly the right area and using an endoscope to see under the tiles?

[mint]

[quote user="Théière"]Who wrote what? I am confused.........[/quote]

Do not be confused, dear Teapot, the sensible, coherent messages are mine and the all-over-the-place, panicky witterings are Q's![;-)]

[Quillan]

Taking on board peoples comments I shall take some photos this afternoon and post them.

[Quillan]

OK here are some photos. Because they are high(ish) def as somebody requested I have just posted the link to each one.

Front door, important as it give a reference point for the inside in relation to the walls.

http://i134.photobucket.com/albums/q99/ckenway/Roof%20008.jpg

Inside, where the leak is. Notice it is the inside of the structural wall which goes to make the end wall of the upstairs bedroom.

http://i134.photobucket.com/albums/q99/ckenway/Roof%20-2%20003.jpg

The roof above the wall which is actually the upstairs bedroom wall and sits on the wall that you see inside the house where the leak is.

http://i134.photobucket.com/albums/q99/ckenway/Roof%20012.jpg

This is where the 'middle' level roof meets the upper bedroom room but not that it is on the opposite side of the wall to where the leek is.

http://i134.photobucket.com/albums/q99/ckenway/Roof%20013.jpg

You see where I am getting mentally stuck is that the roof above the leak is actually also above another room which is above the leak so the water is coming out in a downstairs room. Therefore it would have to run down the inside wall of the room above which it doesn't. It's not logical, not that leaks often are.