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Raised patio

Postby Paul-E » Mon Feb 23, 2009 9:25 pm


I have read the projects section but require clarification on a few things I'm still not sure about.

I want to raise patio to just below new conservatory level which will require me raising a new patio base approx 600mm. I intend using concrete blocks laid flat for retaining walls. A few questions:

1. Does concrete foundations for retaining walls have to be 6" thick or can It be less depth? I think it does need to be 6" because wall will be over 400mm high is that correct? Just checking because if it can be less than 6" I can save pennies.

2. Soil where patio is to be sited is soft but firms up (as suggested in projects section) at about 300mm down so I intend digging out and filling in with either hardcore or scalpings but what should I use? The patio is 7m x 7m so will require a lot of infill and as with everything I need to watch the pennies on this. I assume hardcaore is cheaper so could I use a couple hundred mm hardcore and put scallpings on top of that? Or can it all be done with hardcore or should it be infilled with scallpings alone?

Thats it. Everything else I need to do is clear in my mind after reading projects but the two questions above are just points I need clarification on so thanks.


Thats about it.
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Simply Build It

Postby rosebery » Tue Feb 24, 2009 9:21 pm

Do you mean width or depth? I think you should have no less than 150mm depth. The footings should also extend 100mm either side of the blockwork. How deep are you planning to make the trench?

I'd say your h a r d c o r e with scalpings solution is probably the correct one. What's going on top?

How far just below is just? Be careful not to bridge the DPC level - or you'll get damp!

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