"Muddymike" wrote in message
...

"tjr" wrote in message
...

Hi All,

I'm about to build a greenhouse on some existing paving slabs. The
slabs are very firmly laid, but are not perfectly level. I'm building
a 4' x 6' greenhouse and along the 6' length the slabs are virtually
level, but along the 4' length it drops by about 15mm.
I'd appreciate any advice.


I would not worry about so little fall.


You will have no end of troubles if you do not ensure that the metal base is
horizontal.
I would suggest that you lay it first on your slabs and pack it up at the
low point.
You can then mortar the increasing gap across the base and along one side.
Alternatively you could relay the slabs level.

Regards
Pete
www.thecanalshop.com