Casting staddle stones, anyone tried it?

[johna.clements]

I know I'm resurrecting a two year old thread, but wondering how your staddle stones turned out. I just made a truncated pyramid mould, and I'm planning on casting a couple this weekend. Any tips re. concrete mix or anything else gratefully received.

A 1 in 4 mix (cement/ ballast) with a 0.5 water to cement ration will give 40N/mm2 cube strength concrete. That should be adequate if you will be moving the stones at anytime or putting a bench on top.

Cement will keep for a few years if you keep the air and hence water from it. Wrapped it up in a couple heavy duty bin bags. If it is well wrapped it will keep for a couple of years If you buy 40N prebagged concrete it is likely to have a small amount of moisture inside the aggregate so will not keep as long.

If you put polythene inside the mould it is likely that there will be wrinkles formed in the concrete.

Spray the inside of the shutter with mould oil. You could use cheap vegetable oil but I do not know how it would effect the finish, you could do a test.

If it is going to be below 3C at night make sure you wrap it up to keep the concrete from freezing. Do not mix if it is below 3C.

I would not move the concrete for at least three days after casting or you are likely to knock the corners off. But do release the shutter as much as possible the next day. Keep the concrete damp for the first few days.

40N/mm2 concrete will be up to about 30N after seven days

 

[Spectric]

I thought this was a decorative feature and not structural.

 

[John Brown]

Ok. Thanks.
Yes, structural, supporting the posts that hold my lean-to bike shelter/PV panel. I could probably just use a couple of bricks, but hey, I'm retired, so I can do whatever I like!

 

[johna.clements]

I thought this was a decorative feature and not structural.

If you buy one "handy" bag of all in ballast and one bag of OPC the cost of a weaker mix will not be a lot less. may as well make a structural mix.

 

[John Brown]

If you buy one "handy" bag of all in ballast and one bag of OPC the cost of a weaker mix will not be a lot less. may as well make a structural mix.

Sorry, you've lost me there...
I worked out that I can do both with a single 20kg bag. They're only small.

 

[johna.clements]

Sorry, you've lost me there...
I worked out that I can do both with a single 20kg bag. They're only small.

20kg is not much. That will give you about 8 litres of concrete, so 4 litres each. 2500kg/ m3 no allowance for waste. I assumed you were making some thing a bit bigger like in post. You can buy aggregate in small bags, some place call them handy bags because you can carry them, but not to far or too many at my age.

Ahh sorry guys, I should have been more specific, completely forgot about traditional staddle stones! I was actually thinking more along like the lines of this shape:

 

[John Brown]

20kg is not much. That will give you about 8 litres of concrete, so 4 litres each. 2500kg/ m3 no allowance for waste. I assumed you were making some thing a bit bigger like in post. You can buy aggregate in small bags, some place call them handy bags because you can carry them, but not to far or too many at my age.

Thanks. I'll see what they have at the local hardware store. It's a bit limited round here, and I'd rather not drive to Stroud or Gloucester for the sake of a bag of ballast.

 

[johna.clements]

Thanks. I'll see what they have at the local hardware store. It's a bit limited round here, and I'd rather not drive to Stroud or Gloucester for the sake of a bag of ballast.

There is a place called build it near Slimbridge, have no idea what they are like. nearest place I have worked around there is Ciren.

If you are adding ballast to a 20kg bag of premixed concrete you will not be able to add much to get anything for structural use.

If you are building a carport type structure with solar panels on top it needs to have a proper foundation. The soil, hard standing, existing concrete slab etc you are putting your columns/ timber posts? on needs to be thought about. The main risk will be that the roof goes upward and then lands on something inconvenient. A 15kg blob of concrete is unlikely to be heavy enough to hold down a car port sized roof. If you have valuable things like solar panels on top it could prove expensive.

Why not start a new thread with more details and get a design.

 

[John Brown]

Thanks, but it's tiny. 2440 by 1220 11mm OSB on a 50mm by 75mm frame, covered in heavy duty felt, with a single PV panel around 1750mm by 1050mm.

One (long) end fixed to my shed, and 65 by 100 Douglas fir uprights bolted on a third of the way in from the lower edge. It's not going anywhere.
It's more like a large log store than a carport.
It's already built, but I'm just looking for a way to get the bottom of the uprights off the ground, so they don't rot so fast.
But thanks for your help and for your concern.

 

[John Brown]

P.S. Buildit near Slimbridge is eye-wateringly expensive by comparison with almost anywhere else. I'd rather give money to the local hardware store, all other things being equal.

 

[John Brown]

Just refound this thread, and wanted to add that my staddle stones came out perfectly. I left them in the old sheep drinking trough for a week.