Low pitch roof

[Antony Robinson]

Worked on the roof today finishing off the window that has a 25mm upstand on the top edge.
Had to deform the flashing in a few places but nothing too drastic. All finished off & sprayed with water for a few minutes and all looked OK.
Started on 2nd window but noticed it puddling slightly on the top flashing section of the 1st window.
May change the 25mm upstand back to the normal angle. The window is at a better angle but I think it compromises the top flashing angle too much which may allow water to seep behind the top foam.

 

[noseall]

I feel that setting the window in an unnatural plane to that of its intended 'seating' is going to cause more problems later on. Surely all the flashings are going to want to rise up as the window lifts away from its intended position relative to the roof tiles?

 

[Antony Robinson]

Yes, my thoughts too. Although it's pain it shouldn't take me too long to revert the 1st window back to it's normal plane.
Taking extra care in the corners of the flash kit below the window. Unfortunately I think a small amount of puddling on the corrugated flashing is unavoidable, but hopefully I can get it to puddle away from any joints.

 

[NathanLM]

Hi Antony, Just wondered if your roof had turned out as planned with no more issues or potential leaks?
As I'm about to start my extension very similar in size and pitch also with 3 veluxs/keylite.
I'm thinking of going for a cut around the rear window to compensate pitch? Extension is 4.3m-5.6m so even lower degree roof, i would be grateful for any feedback.

Cheers Nathan

 

[datarebal]

Form small lead flat areas below the house windows and then raise the pitch.

There is not much scope to tweak the standard flashings.. you might think so but wait until you get to the back gutter..

Then its perfectly possible to fabricate lead flashings to do what ever is needed.

 

[NathanLM]

Cheers, I was thinking something like this below which will give me just enough For 15 degree pitch, Nathan

 

[datarebal]

there you go...

 

[Nige F]

Cheers, I was thinking something like this below which will give me just enough For 15 degree pitch, Nathan

Go higher up the window to increase pitch

 

[noseall]

Don't forget that there could be design issues regards the lack of fixing potential at the window abutment (once above the window sill), which in turn could have an effect on the positioning of the Velux. It may also have a visually detrimental effect regards the vaulted ceiling perspective, viewed from below.

Not as simple as you think......

 

[chappers]

yep and certainly don't consider raising the pitch of the veluxes as per what the OP did, hopefully he resorted to a std fit, as he was already at the limit and must have flattened the pitch of the tiles above the velux to about 6 degrees.

 

[datarebal]

Its really not difficult or brain taxing..unless you want it to be.
Visually there will already be a knock on with the vaulted ceiling caused by the steel holding up the rear of the house etc..

 

[noseall]

Its really not difficult or brain taxing...

No - quite. But if the OP has expectations and then finds himself in a position where he has taken advice from the internet then puts a window well into practice, he may be disappointed with visual result from below.

Looking at the image posted with the three Velux and the window well - I'm guessing there will be a flat ceiling area starting directly above and at the head of two of the Velux windows. I'm not sure how the trimming arrangement works but it will require a wee bit of thought especially in view of the fact that the two inner rafter Velux trimmers do not but against the wall, rather they will be cut short onto a bearer.

 

[datarebal]

A small flat ceiling area ..Quite So! What is he getting now? A vaulted ceiling butting a boxed in steel , down one side and up the other. There is a compromise needed. Small flat ceiling or leaking windows? umm Im sure he wont forget his cavity trays either.
Anyway he is to far on I suspect.
Trimmers and doubled rafters Yes you are correct.. perfectly doable though

 

[Antony Robinson]

In the end I didnt bother to try and raise the top end of the velux windows as it was distorting the EDW flash kit too much. Also it didnt make any difference to the bottom end of the flash kit where there was potential for puddling.
At 12.5° the roof and windows have been in for about 7 months and been OK so far. Had heavy & window rain but not had snow yet.
As per many other comments on this thread have advised it's best to avoid the low pitch situation if you can. Unfortunately I didn't realise about my low pitch until quite late in the build stage due to an error on the drawing plans.

 

[Ansar Shezad]

Hi anthony, how did your windows go. Did you get any leaks. Im in more or exactly same situation as you.