The Brew Cabin

Posted: **Wed May 23, 2012 10:35 pm**

Hi, once again, looking for some expert advice!!!

I'm doing a patio between two existing buidlings. I intend to build two retaining walls of about 450mm high between the buildings to form a rectangle of about 4m by 5m.

Have dug out down to solid ground.

I intend to lay wide random stonework onto well compacted limestone crusher run footings to form the retainers.

My questions:

1) I'll need about 10 cubic metres of compacted 'fill' material once the walls are up.

I'd planned to use limestone crusher 40-0 for this, but at 450 deep - thats going to mean a lot of limestone.....

Q: Can I put my topsoil back in and build up in well compacted layers and then top out with Limestone? (this will save on a skip and cut down on the limestone order)

2) I plan to top off with Indian sandstone paving on a full mortar bed..... is it acceptable to lay this directly onto the well compacted limestone?

Any advice much appreciated as always.

Cheers

Ade

Posted: **Wed May 23, 2012 10:45 pm**

1 no it will subside
2 yes by limestone i take it you mean type1 MOT stone
built up in 100 mm layers,each one wacked thats fine
LLL

Posted: **Sat May 26, 2012 10:02 am**

THanks LLL - yes - I did mean MOT 1 but I wasnt sure whether there was a limit to the depth I could build up?

If you had a void of the same dimensions 4m by 5m by 450mm deep - what method of fill would you use?

Is MOT1 the best option?

THanks again

Posted: **Sat May 26, 2012 1:08 pm**

Yes it's your best option you'll be needing approx 14t. With regards digging down all you need to do is remove the topsoil nothing more then cover with a geotextile.

Posted: **Wed Jun 06, 2012 12:04 am**

Thanks for the replies. I know which direction I'm heading in - feel much more confident about it now! Thanks again.

Posted: **Wed Jun 06, 2012 12:48 pm**

I'd fill with cheaper crusher run then top off with mot,

Posted: **Wed Jun 06, 2012 4:33 pm**

What giles said, also crusher run footings, no concrete for a retaining wall?

Posted: **Thu Jun 14, 2012 11:21 pm**

Thanks again for the replies.

I'd assumed that wideish retaining walls in random stone of minimal height, would be stable enough built onto well compacted limestone? After digging out, I found that the ground is very hard and stable, so I'm hoping to get away without concrete footings......

On the topic of Crusher run versus MOT 1, is there any reason why I shouldnt simply opt to use crusher run throughout? After all, if I compact it well enough with the wacker, is there really likely to be any issue?

Thanks again guys.

Posted: **Fri Jun 15, 2012 6:38 am**

Adrian as we share the same initials I will try and be helpful
1 concrete is relatively cheap,dont skimp use concrete for any wall foundations
2 crusher run is basically a skip been put through a crusher
better to use *CLEAN* hardcore in the lower levels ,wacked every 100mm and mot type 1 for the top 200mm
make sure there are no voids in the hardcore,fill these with type 1

cheers LLL

The Brew Cabin

Help!!! advice on patio - Groundworks