Concrete edging

its probably a bit OTT to call this a 'project' but I was after some advice on concrete edging. This stuff:


Its thin rectangular concrete blocks, with a rounded top. We want to create a square area to position a whirlygig on. We didnt want it on grass, as the lawn can become saturated in winter and figured walking on it in that state would churn it up into mud. So we have decided on a surface of loose decorative stones. The edging is to act as a boundary for the stones and stop them escaping.

Regarding putting the edging in:

- to what depth should I set the edging (Slightly higher than grass?) its likely it will get stood on etc at times.

- should I dig out a narrow trench , set the edging on a layer of sand and then backfill? Is it OTT to use something like post-crete to set it in place? What about attaching the blocks to each other? (locktite do a landscape adhesive in the USA, not not UK). I dont want to do anything un-necessary, but want it to be tough and lasting.

- a possible problem is that the foundations of an adjacent fence might limit the depth on one side of the square. In that case is it possible to cut or trim these blocks?

Thanks for any advice.

 

Hi Gabriel,

I did something similar for my arbour - but concrete edgings with paving stones in between. They are easy to break - I broke a couple tapping them with a rubber mallet - so trimming may be an issue unless you can saw them - trying to knock pieces off with a chisel will just break them.

I dug a small trench and simply slotted the edgings into the trench - where there was a gap between the edging and the trench - I filled with soil and compacted down with the side of my foot.

I kept about 2 inches of edging above ground level - this looks about right - isn't too obtrusive - and easy to step over.

It did take some time to get them level - but if you dig out a slightly deeper trench and line with sand then it should be easier.

Concreting into the trench would be a more permanent solution - but a pain if you want to take it out later.

I wouldn't bother trying to connect the blocks - if you take your time and line them up - they will look fine.

Please post up some pics when finished.

Thanks,
Chris

 

Thanks lot clanless, much appreciated.

One other Q - have you had any issue with the blocks sinking over time?

I figured it would be over-onerous to make a foundation (with gravel or whatever), but then I dont want the blocks to sink!

Right enough, our soil is hard packed clay and so hopefully that should be foundation enough.

 

A pleasure to help .

I too have clay soil. My edgings have been in place for a couple of years now and still look fine - they are simply resting on soil. The beauty is - if you just lay on a sand base - you can easily add more sand if they start to sink. But from experience this won't happen.

On a totally different matter - I experimented this year by planting some green manure (field beans) on a patch of clay soil. They have tap roots which break apart the clay and when dug into the soil - raise the level of nitrogen. As an added bonus they are quite attractive to look at. I'll also be trying Vitax Clay Breaker on another area - to see which is best. One day I may actually get the chance to plant some flowers in my garden !

 

I reckon setting them on a sand bed is asking for them to sink and become uneven. What about placing some small pieces of something flat like brick, broken paving slab, etc. in the bottom of the trench for them to sit on?

I've got a 9" angle grinder for cutting slabs, pavers, bricks, etc. but a 4" one can be obtained for less than £20, just cut part way through all round before cutting through with a bolster (rest the edging on soil/grass to absorb the shock). Argos have got one for £12.69 http://www.argos.co.uk/static/Product/partNumber/2378204.htm?cmpid=COJUN&catalogId=10001&cjsurferid=178802742782384126:qSXDSgrQBxRs&_$ja=tsid:11674|prd:1546795&storeId=10151&referredURL=http://www.argos.co.uk/static/Product/partNumber/2378204.htm&referrer=COJUN a handy tool to have, not just for cutting stone, but through metal with another disc. Position the cut edges away from ends and plan your cutting to avoid short lengths that are more easily dislodged, for example use 1 x 900 & 2 x 600 rather than 2 x 900 & 1 x 300 IYSWIM.

The best detail when abutting grass is to lay a row of block pavers around the grass side of concrete edgings and set them below the surrounding grass, then you can run a mower all around it without missing any and having to finish with shears/strimmer.

As for the height above the surrounding lawn level, the higher it is, the greater the force exerted on the edgings when standing near the edgings, and if so low you forget about stepping over them you could end up with a trip hazard.