Firstly, may I congratulate all associated with this site and its excellent advice it gives. Well done.
Q. I need to remove one of two brick courses to enable me to replace a light duty manhole cover with a block paving recess tray of the same size whilst achieving the correct crossfall for my new patio. Can I bed the the new tray on concrete to achieve the correct levels rather than mortar and slate packing? The thickness of the concrete will vary between 30-60mm. I was going to use an all-in-agregate concrete mix with ply shuttering in the opening to prevent spill into the manhole. Are my proposals OK? Any advice would be gratefully received. Thanks.
Drainage
-
84-1093879891
Yep - you can use concrete, David, but it's hard work, setting up the formwork. When it's that sort of depth, we would use slate for the 'thin' end, concrete roof tiles for the mid points, and broken flags for the 'deep' end.
Spread a bed of mortar over the reduced brickwork and then place the frame. Pack each corner of the frame to bring it to 3mm below Finished Paving Level in all directions, and then pack the 'gaps' between the corners with other hard, inert material (tile, flags etc) and fill all gaps with mortar.
Haunch the outside frame flange with concrete and then place the tray. Don't fill it with bricks for 3 days, to give the mortar/concrete a chance to set.
If you still want to do it your way, I'd like to hear how you get on....with pics, if poss. :)
Spread a bed of mortar over the reduced brickwork and then place the frame. Pack each corner of the frame to bring it to 3mm below Finished Paving Level in all directions, and then pack the 'gaps' between the corners with other hard, inert material (tile, flags etc) and fill all gaps with mortar.
Haunch the outside frame flange with concrete and then place the tray. Don't fill it with bricks for 3 days, to give the mortar/concrete a chance to set.
If you still want to do it your way, I'd like to hear how you get on....with pics, if poss. :)
-
68-1093879170
Tony, thanks for the speedy response. Probably will try and go down the concrete route because I have all the materials to hand. Also, the precast concrete reducing ring is visible in the corners just below the last course of brick work - this would help me support the vertical ply shutter. Attempt to do it at the weekend and will send pictures if I don't make a complete arse of it. Thanks Again. David.