Page 1 of 2
Posted: Wed Apr 27, 2011 9:04 pm
by Rad
Not really a paving question but close...Can you advise on the strongest method to fix coping to a single course wall. The reason for my question is the coping is 170mm wide and the wall 100mm. But the coping has to be offset with 15mm overhang one side and 55mm the other. As this is a low wall around a raised pond it is likely that someone may decide to sit on the wall, I am concerned that 100mm contact area against a 170mm offset coping may not hold if pressure is applied to the 55mm overhang causing the coping to pivot and come unstuck.
My questions are...
1) With the above in mind will a 3-1 mortar mix be strong enough to hold the coping in place?
2) Are there any additives which can be added to the mortar to give it greater grip/adhesive properties.
3) Instead of fixing with mortar are there any specialist adhesives available.
Look foward to hearing any suggestions.
Thanks Phill
Posted: Wed Apr 27, 2011 9:17 pm
by peg basher
could always drill and fix a frame cramp to the end of each coping, then bed the next coping over the previous frame cramp so they are not seen??
Posted: Wed Apr 27, 2011 9:44 pm
by London Stone Paving
1. I woudn't go any stronger than 3:1.
2. You could add some SBR to the mix and you could also butter the underside of the coping stones with an SBR/cement slurry though this still might not be enough though if sufficent force was applied to the 55mm overhang
3. Dont know about alternatives to mortar, but if there are any somebody on the site will let you know about it soon.
Steve
Posted: Wed Apr 27, 2011 9:50 pm
by lutonlagerlout
my question is why have you only a 100mm wall round a raised pond?
not enough IMHO
also the reason the coping is 170mm is that it has a 2 drips underneath,these need to be placed equidistant over the wall
if you offset you are making it pointless using a coping so you may as well use a class A engineering brick
SBR mortar will help but there are serious design flaws to begin with
LLL 
Posted: Thu Apr 28, 2011 6:40 am
by mickavalon
Can you not throw another skin of Brick round, tied to the single. The wall may go over if someone sits on it, and your overhang is way to much, if somebody or something puts weight on it, no matter how you fix it, it'll lift.
Posted: Thu Apr 28, 2011 7:28 pm
by Rad
Cheers for the feedback. To answer some of the points raised.
1) The single course wall is not required to hold the water in the pond as it is built around a rectangular holding tank which has self supporting side walls.
2) The wall is 6 courses 1.8m x 1.2m
3) The 55mm overhang is to cover the lip of the holding tank so it cannot be seen.
4) The 15mm overhang is on the outer side to keep drips off the face of the wall.
5) The copings are cut down textured buff 600mm x 600mm paving to match the patio, these are approx 35mm thick.
If anyone has further suggestions on how to fix please let me know.
Thanks Phill
Posted: Thu Apr 28, 2011 7:45 pm
by seanandruby
Could'nt 9inch brickwork ( or is it 215 LLL? ) of overhung by 30ml and then a coping on top of that ???
Posted: Thu Apr 28, 2011 8:34 pm
by specialbranch
how about drilling, plugging and screwing some 50mm Galv angle brackets to the inside of the wall, 2 to each coping?should add a bit of support and wouldnt be too noticable
Posted: Thu Apr 28, 2011 8:42 pm
by Rad
Thanks
The angle brackets would be difficult as we need the liner in place first so cannot screw to inside of wall. Athought is to screw down flat plates or bars which overhang on the 55mm side say by 45mm, two to each coping then mortar on top. What do you guys think of this poss solution?
Phill
Posted: Thu Apr 28, 2011 11:27 pm
by seanandruby
You say: the wall is not to hold the water so why no angle iron. You could use flat metal but we on this site could'nt possibly encourage dodgy building works. How about some photo's ?
Posted: Fri Apr 29, 2011 6:45 am
by mickavalon
Is the brick skin just hiding the walls of the Holding Tank? If you have a holding tank, what do you need a liner for? Nothings going to keep those copings on for long unless you fix them in place with screws or bolts. If your going to try and fix to a liner a s well, your gonna have no joy. Epdm and Pvc liners are almost impossible to adhere to, I build lots of Water features and Swimming Pools, and the best method is to use a mesh or similar to join all the copings together and let their combined weight hold them in place.
Posted: Fri Apr 29, 2011 8:13 am
by seanandruby
A cantilevered coping stone is quite possibly an engineering first. I would worry that as it is a single skin then it would topple. Can you not fix a metal grating' or do you need access. Not enough info' really.
Posted: Fri Apr 29, 2011 10:29 am
by local patios and driveway
if it were my job, a 4-1 semi dry mix with a slurry to bond the mix to the coper and maybe a slurry to bond to the brickwork. try getting that off the next day, you'll struggle even with a bolster
Posted: Sat Apr 30, 2011 6:32 am
by mike builder/landscaper
if we are putting copings on in areas where they might get sat on or trod on by kids taking a short cut to the garden we screw and plug some wire xpamet on the bottom, this is a type of wire mesh used for rendering to stick to. its a time consuming job but once bedded on with your normal mortar bed it wont come loose. i would bed them on the same mix as your brickwork mix so you dont get different coloured mortar. thats a pet hate of mine.
Posted: Sat Apr 30, 2011 11:06 am
by GB_Groundworks
It's out there but you could drill and dowel them with stainless steel dowels and use epoxy resin to stick them in, then bed the copings on a good sir mix.
It's that or drill and plug them and screw them into the wall and then make good the top of the coping