Construction to retain a soil bank - Which method?

[mcquitmp]

Hi,

First of all I'm a complete novice when it comes to building.

I'm constructing a site for a hot tub which is roughly 3m square. The site currently has two walls around two of the sides. I have just excavated the ground to about 35inches below the height of the two walls. The plan is to construct a deck aound the whole think so the hot tub appears to be below ground.

On one of the other sides is now a soil bank which rises slowly into the distance - starting off at about 30inches high - so I need to build some structure to hold the soil in place so it does not wash into my space for the hot tub.

I think I have a couple of choices and I'd just like to get opinions on which one is best or perhaps other alternatives. I'm trying to keep it simple due to my limited experience.

Option 1 - Sink 5 inch round pressure treated posts into the ground to create a palisade. Based on other posts i think this would need to be sunk about 450mm in a trench 300wide by 500mm deep

Option 2 - Using solid 100mm blocks construct a wall. Based on other posts I am thinking of laying the blocks on their side for the full height of the wall as I think I read somewhere that the wall should be 1/4 wide compared to the height. Is this an overkill? I don't really want to get involved in full brick wall construction.

At the moment I favour Option 1. It may be a touch more expensive - but easier for me to do, I think, and I'm trying to minimise the amount of space I use up in the construction.

Any views?

Thanks...
Maurice

[dig dug dan]

I have done just such a project for a client

Firstly, The base MUST have a drain hole , running to a soakaway.
If you do not do this, the hole will fill with water, and the electrics on the hot tub will be knackered.
Secondly, if it is below ground, I would use concrete blocks.
The easiest way is to lay a level concrete base, then dry lay hollow concrete blocks on the retaining sides, then mass fill the blocks with concrete. Ideally, put some rebar into the blocks before hand. It is a quick method and easy for a novice to achieve.
You can of course use he wood for retaining, but it will only last a fraction of the time.

[mcquitmp]

Thanks for the reply.

I know I need to provide drainage for the Hot Tub. Two things...

1. The area I have dug out is half over a soakaway already so hopefully that should help a bit.

2. The level where the Hot Tub will sit is actaully at ground level - so a drain out won't work unless i just rely on the soakaway. I will hopefully be building a small sump with a pump with a automatic flow value so hopefully that will fully sort the drainage.

The actual question I'm trying to answer is - Is the wood solution easier (and adequate) compared to the solid concrete block wall solution I outlined? - bearing in mind I've never done a wall before. I just feel more confident regarding the wooden post solution as some of that is already in my garden holding similar levels of soil (not done by me). I'm not bothered about the appearance as it will all be hidden beneath a deck with an access hatch.

If you think the concrete block solution is best - Is it OK to lay them on their sides to effectively provide a wider (an hopefully more stable) wall that can cope with the weight of the soil?

None of it will be below ground apart from the side which is against the higher level of soil.

Regards...
Maurice

[dig dug dan]

If you are confident about building the wall with blocks then go for it. The blocks on their side will be quite adequate.

Wood will be fine also, but as I say, Will not last as long

it all depends on your budget and timescale

If your hot tub is already going to be sitting on a soakaway, then surel a sump pump will not be needed?

[matt h]

could use railway sleepers, because they are so impregnated will last, either that or greenheart (used in marinas for berthing piers)

[matt h]

could use railway sleepers, because they are so impregnated will last, either that or greenheart (used in marinas for berthing piers)