Velux Window Fitting Question

[Millwright]

Hello, I've just had two Velux windows fitted to an extension. The roof pitch is approx 12.5 degrees.

First off, the underslating. All underslating should overlap, but at the top of the window it comes inwards, underlapping. Now, if we were to get wind driven rain, this is going to come inside isn't it? The tiles are concrete interlocking, are they good at preventing wind driven rain even at lower pitches?

Arrows show 'underlapping' at the top of the window.




Second photo showing the window flashing. What concerns me here is where arrowed, is standing water. What will drain away will only be what 'overflows' from this area. I'm thinking this flashing kit is not suitable for this pitch. It is the EDJ kit, which from my research suggests this is not suitable for anything below 20 degrees.



I would like your thoughts before I address this with the builder as I do have some apprehensions over this. Otherwise, I am happy with the work so far.

Thanks.

Edit: Arrows from photo have dissappeared, but hopefully they are clear enough for you to see.

 

[noseall]

Oh dear.
There are many things that are not suitable for a low pitch roof such as yours. Velux being one. The other is Marley Ludlow (granular) tiles.

You should not be looking at granular tiles for a pitch that shallow irrespective of the fact that the tile type is completely wrong in any case.
Velux should be fitted to pitches no lower than 15°.

 

[Millwright]

Thanks for your reply. Any thoughts on the underlap of the underslating?

 

[freddiemercurystwin]

Haha, I like the way you ignore some major issues and concentrate elsewhere.

 

[noseall]

Haha, I like the way you ignore some major issues and concentrate elsewhere.

A bit like worrying about a paper cut on your finger whilst having gangrene in your shoulder....

 

[datarebal]

As above strictly speaking velux min 15 degrees
The tiles(redland 49 ) are below min pitch too and not much headlap either
The underlay, there is a slight possibility that the fitter may have trimmed around the window with additional underlay rendering the bits you see irrelevant.

Bottom line, roof pitch below manufacturers recommendations

There are tiles that will deal with this pitch just not yours

 

[Millwright]

Haha, I like the way you ignore some major issues and concentrate elsewhere.

If directed at me, I've not ignored any issues. Some good points have been made which I am grateful for and I have taken note. Theses other issues raised I wouldn't have known about right away as I'm not a roofer.

 

[Millwright]

As above strictly speaking velux min 15 degrees
The tiles(redland 49 ) are below min pitch too and not much headlap either
The underlay, there is a slight possibility that the fitter may have trimmed around the window with additional underlay rendering the bits you see irrelevant.

Bottom line, roof pitch below manufacturers recommendations

There are tiles that will deal with this pitch just not yours

Thanks for your reply.

At present until the flashing is fitted, some rain water is coming in through that underlap, so I don't think there is any additional underlay. I did point this out to the builder at first (who did use a roofer to do this work), he said it's to do with no flashing, but I did say it should overlap and not underlap. From what I know, if left like that, any wind driven rain can only come inside.

I'll get up and measure the headlap.

 

[datarebal]

your welcome.
if you ask them to dress the underlay around the window nicely with upstands all round, it will help.
fyi, i have seen velux fitted to leanto at 11.5 degrees and staying weather tight. so you might be lucky.
provided your not in an extremely exposed position..

 

[Millwright]

your welcome.
if you ask them to dress the underlay around the window nicely with upstands all round, it will help.
fyi, i have seen velux fitted to leanto at 11.5 degrees and staying weather tight. so you might be lucky.
provided your not in an extremely exposed position..

Roofer and builder are against dressing and overlap. I personally have no confidence what so ever with this 'roofer'.

I have been on the roof and lifted some tiles, with the builder, and we have found rain water is coming in from inbetween tiles. Builder has suggested more courses of tiles.

I'm border line rejecting this roof and stopping the project until we have a completely different tile. From what I've seen, the slight convex radius on the tile is leading water into the roof and is unsuitable.

Can you suggest a tile to suit a 13 degree roof?

Thanks.

 

[Millwright]

I've just noticed, looking at the redland website, a smooth 49 is suitable for 12.5 degree.

http://www.monier.co.uk/products/product-catalogue/product-range/product/regent.html

 

[catlad]

You wouldn't put granular tiles on a roof that's struggling for pitch,
sounds like the blind leading the blind.

 

[Millwright]

You wouldn't put granular tiles on a roof that's struggling for pitch,
sounds like the blind leading the blind.

Well that's what I said about granular tiles, but this roofer doesn't agree.

I might agree a little about the blind leading the blind, as if the builder is saying something similar to the roofer, it's leaving only me saying these tiles aren't right.

I don't fancy confrontation, but I am the one paying for this and something's got to be done.

 

[^woody^]

the builder is saying something similar to the roofer

I wonder why that is?

That would not be aceptable to bulding control either, and I've got to ask the 'ol chestnut ... "What do the plans say?"

 

[Millwright]

the builder is saying something similar to the roofer

I wonder why that is?

That would not be aceptable to bulding control either, and I've got to ask the 'ol chestnut ... "What do the plans say?"

Original plans are showing a 16 degree roof, but even I must admit, that wouldn't be achievable as we're out 3.3m including thickness of the walls.