Parapet walls and box gutter

[DC1977]

Hi

doing this on our flat roof extension. My dad is the builder lots of experience, dead against it. Could anyone give me the key details Needed to try to reduce the chances of leaks !

thanks very much for any help, much appreciated

 

[noseall]

You have mentioned two of the crappiest building details in our industry. Avoid both like the plague.

 

[DC1977]

You have mentioned two of the crappiest building details in our industry. Avoid both like the plague.

Yep heard this, but we are doing it, happy wife happy life....
Any key things to keep in mind, eg good alternative to doing box gutter in lead (so a bit cheaper)

 

[2020c]

You have mentioned two of the crappiest building details in our industry. Avoid both like the plague.

Are you on about the parapet and the box gutter? If so, im still undecided on which to do on my flat roof. either a full parapet, a 3 sided parapet or just an over hang all around with a gutter on one side.