The Brew Cabin

Posted: **Wed Oct 17, 2007 5:27 pm**

Hi all

I've recently started a patio project in my garden that will consist of an area of sandstone flags with a border of large (250mmx160mmx120mm) kerb stones going around all sides of the patio. The patio will have a slope for drainage (about 1:60) and I wanted the kerb stones on the sloping edges to run parallel with the patio edge (i.e. I want the kerb stones to slope with the patio). The kerb stones will be mortared onto a concrete foundation with a mortared gab between each stone to match the same gap as the patio flags.

I am at the stage of putting in the foundations for the kerb stones but wondered about how I lay the kerb stones on the sloping sides. Do I:

1. lay the foundations with a slope so that I can apply the same amount of mortar for each kerb stone when bedding it in?
2. lay the foundations level and bed the kerb stones in the mortar with a thickness that gradually gets thicker along the length of the slope?

I would of thought that method 2 would be used, but as the slope will have a fall of 80mm and I'm a novice at this, I reckon that the stones would be difficult to lay at the highest end of the slope having to sit on more than 80mm of mortar. Also the stones will be layed in the upright position (i.e 250mm in the vertical).

I'd be grateful for any advice.

Thanks
Neil

Posted: **Wed Oct 17, 2007 6:30 pm**

set the fall to your requirements and lay the kerbs directly on to the concrete, then haunch them. mortar is not required. always use a fixed level to work to when digging out so u keep the subsoil, sub base, bedding layer and paving uniform.

Posted: **Sun Oct 21, 2007 1:55 pm**

For significant slopes, it's always easier to directly bed the kerbs rather than rely on a pre-poured race. Race construction is all well and good if you have a flattish layout, but when dealing with gradients, getting the race to accurately reflect the falls and levels requires it to be poured using a very stiff mix. While it's possible to accommodate minor ups-and-downs using the mortar bed, it's generally regarded that anything more than 20-25mm of mortar would not be acceptable.

There are good reasons for using race beds, but they are rare. I can't see how the use of a race could be justifed on a patio construction project.

Posted: **Sun Dec 16, 2007 5:45 pm**

Many thanks for the advice, I layed the foundations with the gradient I needed and haunched the stones in place. Worked a treat!

Cheers
Neil

Posted: **Sun Dec 16, 2007 6:48 pm**

Got some pictures of what you've achieved so far Neil?

The Brew Cabin

Laying a sloping border of kerb stones