Flags on pedestals

[cw76]

Hi all
Its been a while since I was here!! but you've always come to my rescue when I need a question answered!!!
I have a job where I'm designing flags on pedestal but I'm really stuck on budget..the supplier is saying I need a 400x400x65mm flag where as I was hoping to use a 400x400x50mm concrete flag
(or I was really hoping to use a 600x400x50mm)
Whats you're opinion on using flags on pedestals and is a 50mm thick concrete flag suitable (in pedestrain areas only, its on a terraced roof deck) or would i need to go up to a 65mm thick flag??
Any suggestions..very grateful!!!
Thanks

[Pablo]

Yes 65mm for that system too much of the flag is unsupported. Most suppliers would do a 600x400 decorative flag that would suit but you need to put chairs under them not just on the corners.

[lutonlagerlout]

seek and ye shall find!
LLL

[GB_Groundworks]

laying over an existing patio raises (literally!) the issue of having a surface that is then less than the required 150mm below DPC. The R2 System overcomes this by having the paving laid onto pedestals with 3-6mm joints that allow any surface water to drop down through the overlay patio to the underlying surface.

i though the 150 was also to stop rain bounce back and bridging the damp? how does this work with this system, i like th idea of a new patio before lunch though haha.



Edited By GB_Groundworks on 1264199166

[Tony McC]

They get away with it because the raised flags are alleged to act as an oversize grating and the "actual" surface is that beneath, at 150mm or whatever below dpc.

I've not seen a good challenge to it and its relationship to Part C of the Building Regs that covers this contentious area but I suspect a decent surveyor could make a case against it. However, for now, it seems to be being accepted.

Anyway, back to the OP's query about flag sizes on pedestals: I can't see why a proven quality 400x400x50 (F50) couldn't be used and why an F65 has to be used. I suspect they just want to sell a more expensive product. Have they given a technical assessment that backs up their recommendation?

[ilovesettsonmondays]

i have laid flags on pedestals a few times in the channel isles .but they were always on new offshore banks on their roof terraces.first time we used foam boards underneath .was no good,slabs rocked even though they were on plastic raisers.they found a better system rg falla the next time .we used like a plastic grid system as a base and then put raisers onto that .laid 450 x 450 x 50 mms .looked a good job when finished .only job that i ever laid conservation kerbs on a roof of a multi storey car park .strange them architects.we got 5 pound a metre ,for putting slabs down .i know that you will all think low price ,but you could fly em in .sixty slabs an hour with ease, with someone passing you them