Leaking 15 degree roof with Velux windows and Sandtoft 20/20

[BonnieJ]

We have a new roof which has been leaking since July. It is a small extension with a piched roof with 3 velux windows in. Th pitch is 15 degrees and the tile we've used is the Sandtoft 20/20 tile. The water has been coming in between the velux windows. We have looked into this so much and really don't know what to do at this point. Please can someone help us.

Untitled

• BonnieJ
• 10 Oct 2012
• 1

Untitled

• BonnieJ
• 10 Oct 2012
• 1

Untitled

• BonnieJ
• 10 Oct 2012
• 1

 

[Roofer]

I would be concentrating on the flashing at the bottom of the rooflights.

Can you get pictures of that area?

 

[Roofer]

The Tyvek underlay has been taken onto the top of the third batten down and is sandwiched under the piece of packer batten.

Any water that gets on the underlay won't be able to drain away and will be pushed sideways towards the rooflights.

If there is water ingress further up the roof, perhaps caused by insufficient flashing cover, then that may be the cause of the leak.

 

[upstairscharly]

It shouldn't leak anyway. Membrane isn't designed as a channel for water. Is the headlap 100mm (210mm batten gauge) as specified for 15 degrees or has it been installed at 255mm?

 

[hardmetalking]

15 degrees always seems very low for tiles, zinc would have been a better option on that pitch. It is possible to strip the roof fit 18mm ply onto the roof and have zinc fitted on top?

When you have a pitch below 20 degrees the chances of being plagued with problems increases massively unless you spec a roofing material designed for a lower pitch. How many threads have you seen on this forum complaining of leaks on a low pitch tiled roof?? LOADS!

 

[freddiemercurystwin]

15 degrees always seems very low for tiles, zinc would have been a better option on that pitch. It is possible to strip the roof fit 18mm ply onto the roof and have zinc fitted on top?

When you have a pitch below 20 degrees the chances of being plagued with problems increases massively unless you spec a roofing material designed for a lower pitch. How many threads have you seen on this forum complaining of leaks on a low pitch tiled roof?? LOADS!

HMT, you know your stuff that's unquestionable but really, your continuous bleating on to people to get a zinc roof is a little tiresome. The tiles are designed for the pitch as are the roolights. There is a problem somewhere not caused by the pitch of the roof being too low.

 

[hardmetalking]

Velux roof lights are guaranteed down to 15 degrees so is it best practise to fit them on there limit.......No.

I'm sure the roof structure can fluctuate by half a degree here and there meaning the roof lights are no longer guaranteed.

I bleat on about hard metals because it's a long term guaranteed option, as I said before how many threads complain of leaks on low pitch roofs? And many threads complain about leaking zinc roofs?

Freddy if I'm wrong please tell me?

 

[freddiemercurystwin]

You're wrong.

 

[hardmetalking]

Even the roofs shown on the sandtoft website aren't 15 degrees! Installing a product on its limit is an unecessary risk. We don't install zinc on its limit it wouldn't be good practise.

 

[hardmetalking]

Now you sound like my wife..........

........can't win an argument with her either

 

[freddiemercurystwin]

And don't you forget it!

 

[datarebal]

20 20s work just fine at this pitch ...at the correct gauge.
this is a straight forward roof with nothing complicated at all.

possible problems, water getting in above the windows possibly flashing at the top of the slope or missing trim screw in velux... strictly speaking the velux are not positioned correctly in relation to tile courses or vice versa. Note low lap on back gutter with a bit of batten used as kick.
strange that i see no nails used or clips.......???

 

[Nige F]

. Note low lap on back gutter with a bit of batten used as kick.
strange that i see no nails used or clips.......???

I see what you mean - what about being just 1 tile between each velux I feel the need for a flashing surrounding the top and middle of each row of velux`- I`m always a bit dubious of their supplied flashing . But I`m sure they are perfectly OK in the majority of installs

 

[Nige F]

It is possible to strip the roof fit 18mm ply onto the roof and have zinc fitted on top?

!

They want red - not zinc grey

 

[hardmetalking]

We do fit red zinc :