Screed or concrete

[Rocketman]

A problem... hope someone can help...

Six years ago I had an entension built... however, when the builders dropped the concrete pad they chucked it around a bit outside the outer brick wall skin. I've finally got around to smartening all this up... but now I have one hell of a leveling job to do. This slopped concrete is very thick in places and very irregular, fluctuating between about 4 and 2.5 courses below the damp-course. I have dug away all the loose material... what's left is very solid indeed.

Question: I would like shutter a strip (about 30cm wide) along the wall and raise the level to about 2 courses (with concrete?)... my worry is that in places the concrete will be only half a course thick (3.5-ish cm) and will crack. Will this be ok or is there a screed (suitable for outdoors) I should use instead?

Please note the strip will not be walked upon... actually the shuttering I mentioned above is a 0.5m retaining wall holding back the front lawn (i.e. this is a 30cm ditch along the front of the house)... but I'm worried I'm complicating the matter somewhat.

Hope that's all clear... I'll try to post some pictures tomorrow.

Appreciate your time.

Many thanks,

Rob.

[lutonlagerlout]

why not do it with deco gravel?
LLL
pics would be handy

[Rocketman]

Many thanks LLL...

I must admit I hadn't thought of gravel... it would be the easier option but I was hoping to whisk any ditch water that forms (rain and from weep holes) down to the drain at the far end and away from the crappy foundations of this old house (I say crappy... they show absolutely no signs of moving

Here are some piccies (hope this works!)...

Thanks again,

Rob.

[lutonlagerlout]

rocketman,really you should have built a land drain down the back of the wall on the grass side

1 remember 150 mm below DPC is a must

2 does your lawn fall away from the house?

3 picture 2 looks like bricklayers snots to me,get a hammer and bolster and hack them off

4 you can infill with concrete but be very conscious of 150 mm below dpc and keep the crete angled away from the house

cheers LLL

[lutonlagerlout]

PS are those concrete blocks?
they look a bit like agolites,which are NOT suitable for below ground
concrete all the way below ground!!
LLL

[Rocketman]

Many thanks for the help LLL...

I thought about the land drain... I guess it's not too late to get the spade out again. Don't suppose back-filling with pea-gravel would serve the same purpose. Thought not.

1) 150mm... I make that two courses... I'm aiming for three for good measure but that would make the concrete a bit thin in places (hence my original question).

2) Lawn is flat away from the house (appreciate it looks sloped in the piccie).

3) Will get chiselling... thanks.

4) Was aiming to angle away from the house and down towards the drain at the bottom.

I bloody hope they're concrete blocks... that's what I asked for and made it clear at the builders yard they were for a retaining wall. They are damn heavy... and show on my invoice as "SOLID DENSE BLOCK 100MM 7N" (item code 700064 from TPs). Please tell me that's ok

Much appeciate your help and advice.

Rob.

[lutonlagerlout]

yes blocks are fine,bit of an odd one what to do with the gap though,its a bit tight for doing a land drain as really the drain should be below the lowest level
i wouldnt really recommend doing concrete in here as any problems and you are stuck,look here near the bottom for a land drain detail

land drainage
cheers LLL

[seanandruby]

you will probably need an expansion joint between wall and concrete.