What are the sloping parts of a parapet drain made of on the roof?

[ey143]

Just had a ground floor extension built and flat roof near complete. The parapet drain which slopes to the sides are made of wood and has been covered in GRP roofing and then comes out to the side into the hopper.

Is this how parapet drains are built? Not out of plastic or something?

 

[freddiemercurystwin]

What do the drawings show?

 

[ey143]

We changed what the architect put on the approved plans. I hadn't noticed from his 1900s style hand drawing that he hadn't put parapet drains in there which I asked him to and instead he did the cheaper version of where the water runs off into the gutter.

 

[^woody^]

Made of lead normally

 

[ey143]

The bit on the flat roof? I know lead flashing probably covers the bricks on the vertical drop.

 

[ree]

As above, parapet chutes are best made from sheet lead. Attempting to install them retrospectively could be a DIY nightmare.

If your concern is some kind of built-in flat roof parapet edge guttering then that too could be in lead or, more likely, the roof covering material such as GRP or felt.

Perhaps post a pic?