Terracing a 45 degree chalk slope with limited room for mistakes.

[spamlet]

We have an old house built on a thin hard layer of chalk on a steep hillside. There is an 8 foot 'patio' area behind the house, before the scarp slope drops away at about 45 degrees, to drop about 10 feet to the next flattish layer.

Originally, thin concrete shuttering had been used to create 5 narrow terrace beds, but this had no foundations, and so, over the years fell away as it became cracked and was pushed forwards by the roots of inappropriate planting.

The slope thus needs to be both stabilised once and for all, and reterraced for plants as it takes up most of the garden.

I have removed all the old shrubs and thick rooted plants, but need to reconstruct some kind of terracing. I thought this time there should be three bed terraces with two path terraces between them.

How can I make stable footings for terrace walls so that they will not tip over again, and, at the same time, will not remove any more solid chalk from the rather small distance between slope and house? Should I, for instance, put piles in deeply, at the top of the slope, to hold back the patio, and then work down - or would this risk breaking the face of the slope away?

Starting at the bottom sounds more sensible, but I can't imagine quite how to go about it.

There is also a problem with materials, as there is no local rock to be had, and several tiers of bricks or breeze blocks would look rather too much I think ( and the latter, rather tacky...). Also the budget is not that healthy.

Any useful tips would be appreciated.

Cheers,

S

[Andrew Mawson]

narrow

inappropriate

should be

patio, and

On the cuttings for railway embankments and motorways they drive a screw pile at an angle into the flank of the embankment

[Broadback]

Be very wary. I had a similar scenario, though not chalk. I employed a landscape "expert" who recommended sleeper walls, and terracing. this he did and it looked fine and gave me two areas to make raised beds. However after a few months the sleeper walls started to creep out. Questions to the landscape man evoked no answers. So I had to engage a solicitor. The problem was eventually solved but caused a lot of heartache, especially for my wife.

[Mike Tomlinson]

In article , Broadback writes

By "sleeper walls", do you mean walls created using old railway sleepers, or is it a term for a particular building/bricklaying technique?

[dennis]

Leave it as it is and build a deck to level the top and use hanging baskets for the plants at the sides. Just make sure you use thick posts as they are 10' and you don't want them to bend much although they can be tied with some ply sheets to make them very rigid.

[The Medway Handyman]

Ply would make the structure rigid, but not very pretty. Diagonal braces might be beter?

[dennis]

You can always put a trellis on them. 8-)

[meow2222]

It sounds from what you say as if the artifical terracing held it all in place until the plant roots took over the job, which is the most durable permanent solution that exists. Why did you rip these roots out? Maybe if you explain what the problem is more clearly.

NT

[spamlet]

Thanks to all who replied. Have been away from the pc lately, so it is good to see so many thoughtful suggestions.

The Screwpile place is actually not far away and may be worth a visit - though it seems a bit of a large scale concern for us to be dealing with.

Point taken re trusting the railway sleeper brigade: we had a small retaining wall made of these put in vertically at one section of the bottom of the slope: the 'experts' were actually surprised to find chalk when they started digging...

The 'unfoundationed' concrete retaining faces of the original terraces WERE destroyed by foolish planting schemes. Though it is true to say that the large Sumach, at the top of one side of the slope is probably now all that is holding things together on the steepest section, its roots undoubtedly did not help retain the concrete facings, when they were all undermined. Similarly, Mahonia roots go right into the solid chalk, and widen every year, acting as wedges. They are also completely impervious to weedkillers; as are the Japanese Anemones, and Green Alkanet, which also multiply at an astonishing rate.

The other main 'levers' planted, which forced the concrete to break, were Yucca plants, which have very wide new roots - every year - and Bergenia, which are nearly as bad. Thankfully, these two are at least, easy to kill!

Not sure how I could go about decking over the patio area to level it all either: I'd still have to do something with the slope...

Anyhow,

Thanks to all.

Cheers,

S

[meow2222]

I'm still unclear why you think the plant roots were making the ground unstable. That the concrete was only temporary is normal & expected. Are you familiar with how plants are used to stabilise steep slopes?

NT

[spamlet]

No I cannot make anything more clear: Plant a bamboo seed in your ear and see how long it takes to stabilise your head.

S