Roof leaking that has wrong tiles for pitch.

[axil23]

Have had this house for a few years and this roof has leaked 5-6 times every time there is a heavy downpour. The original roofer has retired so I can't get him to re-evaluate the options. What I have been told is that the roof tiles (redland 20/20) are not the right tiles for a roof like this with a 18 degree pitch. They say the only option is to take up the tiles and relay new ones.

I am not to keen on that as I don't want the main roof tiles to be different then the tiles on this extension.

Is there any other thing that I can try or is replacing the only option?

Are there any tiles that would match these?

View attachment 109907

 

[chappers]

not sure if they are 20/20s I have only seen single 20/20s and they should be good down to about 15 degrees, but you would need to increase the headlap at such a low pitch.
Just had a look and for the new 20/20s they say 100-125mm headlap at 15 degrees

 

[John D v2.0]

That membrane should be draped between the rafters, it will be collecting water above the battens and it might be finding a way in too.

 

[axil23]

That membrane should be draped between the rafters, it will be collecting water above the battens and it might be finding a way in too.

Yeah I think that is happening. Would you suggest a fix for this or still changing the tiles option?

 

[axil23]

Basically I am willing to give anything a go before shelling out on a new roof.

 

[John D v2.0]

Well you can do that but you have to take all the tiles off, re batten with new underlay membrane, then put the tiles back. So basically re roof with the same tiles.

 

[freddiemercurystwin]

The membrane’s function is to get the shell waterproof during re-roofing and as a back-up should a tile slip during its lifetime. Whilst I would agree that a taught membrane can create problems if the membrane is being used to waterproof the roof the problem is the tiles not the membrane. So if you’re gonna strip the roof then you need to establish why the tiles are letting water through before you go through all that.

They’re not Sandtoft 20/20s BTW, this is a Sandtoft 20/20:

 

[axil23]

They are redland 20/20 apparently.

 

[axil23]

I think these are the ones http://www.monier.co.uk/products/product-catalogue/product-range/product/duoplain.html

 

[freddiemercurystwin]

Actually they appear to be Redland Monier Redland Duoplain http://www.monier.co.uk/products/product-catalogue/product-range/product/duoplain.html

Minimim pitch 25°!

You could get your tape measure out and check:

 

[axil23]

Yep these are the ones. So a roof change is the only option as these are for 25 degrees?

 

[freddiemercurystwin]

I think these are the ones http://www.monier.co.uk/products/product-catalogue/product-range/product/duoplain.html

Gah, you posted as i was googling!

 

[chappers]

Yep these are the ones. So a roof change is the only option as these are for 25 degrees?

Essentially yes but there might be the possibility to save some effort by using another tile on the same battens, can you measure the gauge in mm (the distance from the top of one batten to the next). If its somewhere over about 200mm, ideally 210mm or above, you could swap them out for 20/20s., you would
Another thing you could try, but with no guarantee of success is to re batten at the minimum gauge for the duos and relay those you would of course need some more, I know they say minimum 25 but most are good for a few degrees more and you can always reduce the gauge by a bit below the minimum too, depending on coursing