Parapet wall capping

[freddiefox]

Hello,

Despite Googling alot I'm unable to find if there is a specific measurement required for building regs regarding overhang when capping a parapet wall with coping stones?

I have a single story extension, double skin + cavity - 2 sides measure 275mm across the cavity and the front measures 290mm. Would a 350mm wide coping do the job i.e. 30mm overhang on on each side on the widest part, or do I need to up to 380mm or 400mm?

Here's what I'm looking at:-
https://www.roofingsuperstore.co.uk...red-coping-stone-600mm-x-350mm-sandstone.html
https://www.roofingsuperstore.co.uk...red-coping-stone-600mm-x-380mm-sandstone.html
https://www.roofingsuperstore.co.uk...red-coping-stone-600mm-x-400mm-sandstone.html

While I'm at it, can anyone advise what else I need to order for the bricky? I'm thinking I need the following:-
DPC and Cavity Support
https://www.roofingsuperstore.co.uk...vity-support-and-closer-100mm-24m-length.html
Polysulphide sealant - unsure how many I need for 28 Copings on approx 15M run.
https://www.roofingsuperstore.co.uk...low-modulus-pu-adhesive-and-sealant-grey.html

Thanks in advance!

 

[freddiemercurystwin]

If you need to use that stone capping then I would go with the 380 but only to ensure that the drip is kept away from the outer faces of the walls.

That said this was discussed lately and conclusions seem to err towards does having an overhang really matter anyway, just how much water will run off the capping anyway. Sometimes just a lead capping will do. //www.diynot.com/diy/threads/avoiding-overhang-at-boundary.453169/

 

[freddiefox]

Thank you! I'll order the 380's

Do you know what else my bricky will need? We're just paying day rate and supplying the materials.

 

[Nakajo]

Cup of tea and a chocolate biscuit.

 

[^woody^]

Cavity tray and weep holes?