Eaves on a hipped roof

[tufty]

Firstly hi to all and thanks for any replies.

I am currently mid way through a 4.3 metre extension to our bungalow and in the throws of doing the hipped roof.

Its going well with no major problems at present and building control happy with my work.

Two questions guys please.

I note that some roofs ( is that the correct grammer ?) have a ply sheet added before the end of the breathable membrane, where or just before it meets the gutter at eaves level.

Now i assume that this is to allow the membrane a nice run into the gutter and to prevent any pooling of water should it get that far.

Firstly is it required as my existing roof does not have it, and secondly what is a sensible thickness for it, and what width would you recommend

I am about 2 foot short of the eaves with my membrane at the moment and wont progress until i have your views.

I thought about 9mm ply and about 300mm wide.....sound reasonable ?

Thanks again

Tufty

 

[Roofer]

Your interpretation of what it is and what it does is correct. 9mm would be fine and the width needs to be enough to make sure it has a fall, normally about 150mm is sufficient.

However, most of the time a plastic 'felt support tray' is used instead of the ply; the tray not only supports and drains the underlay but has the additional advantage of overhanging the fascia into the gutter.

Most vapour permeable underlays are not UV stable so a strip of 5U felt has to be put in at the eaves. The felt support tray eliminates the need for the 5U.

 

[noseall]

We use taught 18" dpm.

 

[tufty]

Thanks Roofer, and noseall.

Looks like a felt support tray it is then, i will be off to my local suppllier soon as.

Whilst you are here, my roof pitch, (sorry slope) is 41 deg, and as before my existing roof does not have this but is there a need for a sprocket at the eaves and or do i go for just the support tray on the eave end.

I assume not ?

And one more if i may, being cheeky !.....as before i have membraned almost down to eaves level but is it beneficial to put an additional capping over ridge and hip boards.

Thanks guys for all your help

Tufty

 

[Roofer]

The reason for the felt support is to stop any water that gets on the underlay ponding behind the fascia and finding its way into the soffit. It is a fairly recent improvement and is still not used in 100% of cases.

I would not bother trying to change your existing construction - just ensure that any breakages etc are repaired ASAP.

No additional membrane is required at ridge and hips provided the general underlay is well lapped.

 

[tufty]

Thanks roofer, top stuff