Two weeks ago I poured myself a glass of wine to celebrate two years of part time effort in a shambolic back yard in Cornwall to make it a Courtyard with slate patio, paths and fountain for my wife upon our 25th Wedding anniversary. Had to learn lots of new skills. I felt great, even if it is a year late.
Over my wine I thought I would investigate a smell of kerosene around the oil tank that I had increasingly smelt that day. To my horror I discovered a small flow of oil from a tiny crack. I sealed it with soap (the ultimate trick I was advised about) and had the tank fuel pumped out into a loan tank until I could cure a couple of tank base installation problems.
Whatever the rules were when this tank was installed by a previous owner have now clearly changed. The larchlap fence behind is a no no. So I have to build a block wall which I'll likely face in slate. It will have to be 2m high because of a neighbour's building behind.
I have built dense block walls at a rather lower height before, but in part this will be a retaining wall (ground behind some 2 feet higher). Also the land behind might be developed so I want no future problems. Thus I'm looking at 18 inch deep foundations (possibly reinforced if my neighour agrees), 24 inches wide within the subsoil, and a hollow block (8 inches wide) rebar strengthened wall with horizontal mesh every 4 courses. I'll do a 3.5 metre run this year to slightly exceed statutory requirements, and the remaining 5.5 metres when I have to although the foundations will be fully in in one go and the 5.5 metre run will have block to ground level with the old wooden fence on top.
After much research I felt quite comfortable with this general plan but then thought about getting started. I'll use a contractor for the excavations, and ready mix for the foundations: I have already disposed of 3 x 8 cubic yards to date all dug out and skipped by hand and I'm not young anymore! Anyway everything takes much longer than I plan if I do it myself and I want heat in the house by the end of September!
And so to laying the hollow blocks. As I understand it one inserts rebar in the foundations as they go off (one per block) , and mounted vertically (or previously tied in if appropriate with horizontal mesh in the Foundations), rising four courses. Hollow blocks are laid with further rebar inserted to rise in total 4 more courses than the top height of the first rebar. Every four courses a "fill mix" is poured into the block cavities and when that has set the next four courses can proceed. Then it is step and repeat to the necessary height. As I say I plan also to use horizontal mesh.
My questions are these:
1. What is the best way to apply mortar to a hollow block to make an effective joint, whilst keeping the interior of the block "Clean". I have thought of making inserts out of plywood for the block so that mortar might first be applied to the block to be levelled and yet no mortar fall into the hollow of the previous course (or rather less mortar).
2.What is the better "fill mix" when pouring every four courses into the hollows? I have seen reference to concrete, mortar and even subsoil!
Your advice is much appreciated.
Thank you.
Over my wine I thought I would investigate a smell of kerosene around the oil tank that I had increasingly smelt that day. To my horror I discovered a small flow of oil from a tiny crack. I sealed it with soap (the ultimate trick I was advised about) and had the tank fuel pumped out into a loan tank until I could cure a couple of tank base installation problems.
Whatever the rules were when this tank was installed by a previous owner have now clearly changed. The larchlap fence behind is a no no. So I have to build a block wall which I'll likely face in slate. It will have to be 2m high because of a neighbour's building behind.
I have built dense block walls at a rather lower height before, but in part this will be a retaining wall (ground behind some 2 feet higher). Also the land behind might be developed so I want no future problems. Thus I'm looking at 18 inch deep foundations (possibly reinforced if my neighour agrees), 24 inches wide within the subsoil, and a hollow block (8 inches wide) rebar strengthened wall with horizontal mesh every 4 courses. I'll do a 3.5 metre run this year to slightly exceed statutory requirements, and the remaining 5.5 metres when I have to although the foundations will be fully in in one go and the 5.5 metre run will have block to ground level with the old wooden fence on top.
After much research I felt quite comfortable with this general plan but then thought about getting started. I'll use a contractor for the excavations, and ready mix for the foundations: I have already disposed of 3 x 8 cubic yards to date all dug out and skipped by hand and I'm not young anymore! Anyway everything takes much longer than I plan if I do it myself and I want heat in the house by the end of September!
And so to laying the hollow blocks. As I understand it one inserts rebar in the foundations as they go off (one per block) , and mounted vertically (or previously tied in if appropriate with horizontal mesh in the Foundations), rising four courses. Hollow blocks are laid with further rebar inserted to rise in total 4 more courses than the top height of the first rebar. Every four courses a "fill mix" is poured into the block cavities and when that has set the next four courses can proceed. Then it is step and repeat to the necessary height. As I say I plan also to use horizontal mesh.
My questions are these:
1. What is the best way to apply mortar to a hollow block to make an effective joint, whilst keeping the interior of the block "Clean". I have thought of making inserts out of plywood for the block so that mortar might first be applied to the block to be levelled and yet no mortar fall into the hollow of the previous course (or rather less mortar).
2.What is the better "fill mix" when pouring every four courses into the hollows? I have seen reference to concrete, mortar and even subsoil!
Your advice is much appreciated.
Thank you.
