Pebbles/chippings around the wall?

[LLL]

Hello, the plants and soil around my house outside wall are removed and you can see the brick pavement is around 35cm away from the wall and the trench is ready. After checking online and talk with GPT, I plan to use concrete to make a low slope against the wall to protect it from potential rain water, then add type 1 MOT stone as the base, the white decoration stones are on the top. Can anyone tell is this a good idea? There are two types: pebbles and chippings, which is better for this case? 
thank you

[Mr Punter]

Don't make the finish level too high.  Leave it so there is still a brick exposed under the air brick.  I doubt you will have space for your proposed materials.  You could just have weed membrane and shingle.

[saveasteading]

Agreed with @Mr Punter.

 

I've just done this to lower some ground that was too high. Finished level of gravel at a brick, or more, below the dpc. This is so that splasing stays below the dpc. My gravel is about 25mm deep on membrane but deeper would be better. Use non-woven membrane (looks like felt, not cloth) so that weeds don't get through.

Be sure that the ground below is permeable, or dig more out to hold more water.

 

Pea shingle is a third the price of crushed stone and easier to handle. And at some stage it will be filthy and need cleaning or replacing so again pea gravel as new stuff will match.

 

[LLL]

46 minutes ago, saveasteading said:

Agreed with @Mr Punter.

 

I've just done this to lower some ground that was too high. Finished level of gravel at a brick, or more, below the dpc. This is so that splasing stays below the dpc. My gravel is about 25mm deep on membrane but deeper would be better. Use non-woven membrane (looks like felt, not cloth) so that weeds don't get through.

Be sure that the ground below is permeable, or dig more out to hold more water.

 

Pea shingle is a third the price of crushed stone and easier to handle. And at some stage it will be filthy and need cleaning or replacing so again pea gravel as new stuff will match.

 

Thank you so much both. Can I ask where the DPC is? Is it just above the air brick? To be honest, i really can't see anything different from other layers of bricks. But i do see a row of small holes on another side of the wall just above the air brick -- about the solution, are we talking about making a concrete slope aginst the wall? or adding a DPM against the wall? the upper of the concrete should be 1 brick lower the air block then?

 

[saveasteading]

Not concrete against the wall. Let the water drain down.

These holes in the mortar half way between air bick and render look like injection holes for a chemical dpc. 

As if the building didn't originally have one. 

Other people may know better than I.

 

The air brick is probably to ventilate under the floor. Is the floor timber?

Where is the floor level relative to this picture? The doorway is the easiest guide.

[Redbeard]

I wouldn't put any concrete against the wall. It gives you a joint which will crack and open and let moisture in. Membrane and gravel and, if you have somewhere for the water to drain to, perforated pipe in the bottom of the trench - although it doesn't really seem deep enough to count as a trench, or perhaps the pic is misleading. How deep is it?

[LLL]

1 hour ago, saveasteading said:

Not concrete against the wall. Let the water drain down.

These holes in the mortar half way between air bick and render look like injection holes for a chemical dpc. 

As if the building didn't originally have one. 

Other people may know better than I.

 

The air brick is probably to ventilate under the floor. Is the floor timber?

Where is the floor level relative to this picture? The doorway is the easiest guide.

indeed it is floor timber, there is a crawl space below the ground floor and the air brick is for venting the crawl space. If no concrete slope, will the water drain to somewhere close to the foundation and the well? 

[LLL]

1 hour ago, Redbeard said:

I wouldn't put any concrete against the wall. It gives you a joint which will crack and open and let moisture in. Membrane and gravel and, if you have somewhere for the water to drain to, perforated pipe in the bottom of the trench - although it doesn't really seem deep enough to count as a trench, or perhaps the pic is misleading. How deep is it?

Thanks for confirming again, I don't see any drainage close to the wall, but the bottom of the trench (which is around 20cm) is sand, which should be good for the water go away. The trench can be deeper if i dig the sand away i believe.  it seems the sand layer is quite deep and shoould be good for water draining, is it necessary to add a membrane or pipe? 

[saveasteading]

Membrane yes. It prevents the gravel and sand mixing and becoming nearly a solid.

[LLL]

Can I ask how to add the membrane? Are you talking about the one lying under the stones used for stopping the weeds (Option B in my pic) or the one against the wall (Option A) to protect it from the rainwater? thank you. 

 

[saveasteading]

It is B, but turning it up against the wall is good. Just make sure it is below the gravel for appearances.