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Posted: Fri Nov 09, 2012 6:21 pm
by Morse
I have had a 11 metre by 5 metre patio installed. The flags are Raj Indian Sandstone measuring 900 by 600 and 25 to 35mm thick.
They have been laid on a dry mortar mix, but on the perimeter the flags have been laid on a wet morter mix which is about 50 to 70 mm thick.
At a later stage I want either install a stainless steel and glass balustrade or a wrought iron one. To secure the posts to the patio I was advised not to use Rawlbolts because they could break the flags.
Can you please advise me on the best way to secure the posts to the patio including width/length of bolts.
Posted: Fri Nov 09, 2012 6:36 pm
by Dave_L
Surely any posts/rails/fencing should be ragged into a suitable concrete base and not just the flags? Surely the leverage from someone leaning (or falling) against the balustrade could tip the flags up??
Posted: Fri Nov 09, 2012 7:44 pm
by Morse
I should have explained the bolts will go through the flagstones and into the concrete below a total depth of approx 70 to 80 mm
Posted: Fri Nov 09, 2012 7:46 pm
by msh paving
Don't even think of bolting down to slabs, first person to lean on them will push them over.
the only way is concrete pads in the ground,then bolt the post with thrubolts or some type of anchor bolts,
pad i would suggest 450mmx 450mmx 200mm you need enough size to allow for people pushing on them,could be bigger if you so wish MSH 
Posted: Fri Nov 09, 2012 7:48 pm
by msh paving
Morse wrote:I should have explained the bolts will go through the flagstones and into the concrete below a total depth of approx 70 to 80 mm
70MM thick sand /cement will not hold any type of bolt fixing, MSH
Posted: Fri Nov 09, 2012 8:07 pm
by Tony McC
Dave's right. You can't anchor to those wafer flags. If they don't shatter during the installation, they will within the first 3 months. They just cannot take the stresses imposed on them by a rail system.
You have to go through the flags and either set the uprights into concrete or affix to a padstone beneath the flags....
Posted: Fri Nov 09, 2012 9:55 pm
by lutonlagerlout
agree with the boss here ,posts should have been set first
if doing them now use a 100mm diamond core cutter and dig a hole 600mm deep
ball-breaker i know but better to do it once
LLL
Posted: Sat Nov 10, 2012 9:11 am
by seanandruby
Pity your so far away, i have a load of threaded bar , nuts, washers, 90% angled cleats, ec410 and applicator i had for a job i did'nt get. Still they'll come in handy one day :;):
Posted: Sat Nov 10, 2012 5:15 pm
by gonchy
anotherway ive seen them installed on already layed yorkstone was to an old listed building we was recutting the roof on was they cored drilled 4" holes down through the stone as they didnt want it lifed slotted the rails in and concreted or was is resin cant remember now but it did look good when done only an idea as its not my field