I'm planning to put a patio in a small area of our garden that was a dumping ground for the previous owners. I've cleared it up and dug down a fair bit:
The wall on the left is a retaining wall holding our sloped lawn up the hill and to the right is the back of our garage. In digging out the area I discovered what seems to be a drainage pipe for the retaining wall, as can be seen above. I will leave the pipe as-is but since I don't want it visible in the final construction its presence sets the minimum height of the patio. I'm also trying to maximise the patio area and avoid steps if possible. I would therefore have the patio start to the right of the pipe and cover the pipe in gravel. However, the top of the pipe is level with the top of the second brick layer above the ground on the garage. The bottom of the lowest brick layer is the same height as the garage floor inside, so I don't want to have water sitting above that level in case that causes damp issues inside. I would put a slope on the patio towards the garage for drainage but 2 bricks worth of height over only a few metres would make the incline a bit ridiculous, so I don't want to do that. So, my current thinking is to leave a fairly large gap between the patio and garage, approx half a meter, and dig a trench at the garage wall and fill it with some large gravel or decorative stones to allow plenty of drainage before the wall. I wanted to check with folks here whether this seems like a good plan. Should I rather be thinking of putting in a french drain at the garage wall or avoiding a patio altogether here?
Hopefully this helps show what I'm proposing:
Another question I have is about the type of sub-base aggregate to use if I go for a patio. Type 1 MOT is the easiest to get ahold of and cheapest but doesn't drain as well as type 3 I believe. The blue pipe seems to be working - not filled with silt or anything - so can I assume it's handling the drainage for the retaining wall and I don't need to therefore factor in drainage for that too here, so I can get away with type 1 for this small area? I believe type 3 needs a proper petrol plate compactor which I'm hoping to avoid having to hire as it'll be a right pain to get to this area of the garden. I read type 1 can be compacted with a bit of effort using a hand compactor, so that would be my preference.
The wall on the left is a retaining wall holding our sloped lawn up the hill and to the right is the back of our garage. In digging out the area I discovered what seems to be a drainage pipe for the retaining wall, as can be seen above. I will leave the pipe as-is but since I don't want it visible in the final construction its presence sets the minimum height of the patio. I'm also trying to maximise the patio area and avoid steps if possible. I would therefore have the patio start to the right of the pipe and cover the pipe in gravel. However, the top of the pipe is level with the top of the second brick layer above the ground on the garage. The bottom of the lowest brick layer is the same height as the garage floor inside, so I don't want to have water sitting above that level in case that causes damp issues inside. I would put a slope on the patio towards the garage for drainage but 2 bricks worth of height over only a few metres would make the incline a bit ridiculous, so I don't want to do that. So, my current thinking is to leave a fairly large gap between the patio and garage, approx half a meter, and dig a trench at the garage wall and fill it with some large gravel or decorative stones to allow plenty of drainage before the wall. I wanted to check with folks here whether this seems like a good plan. Should I rather be thinking of putting in a french drain at the garage wall or avoiding a patio altogether here?
Hopefully this helps show what I'm proposing:
Another question I have is about the type of sub-base aggregate to use if I go for a patio. Type 1 MOT is the easiest to get ahold of and cheapest but doesn't drain as well as type 3 I believe. The blue pipe seems to be working - not filled with silt or anything - so can I assume it's handling the drainage for the retaining wall and I don't need to therefore factor in drainage for that too here, so I can get away with type 1 for this small area? I believe type 3 needs a proper petrol plate compactor which I'm hoping to avoid having to hire as it'll be a right pain to get to this area of the garden. I read type 1 can be compacted with a bit of effort using a hand compactor, so that would be my preference.
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