Polycrub Part 1

 So we have decided that we would like a larger greenhouse. Polytunnels are popular here , but the average life expectancy is 3-4 years ,shredded eventually by the wind.  We heard about the polycrub 

As they are made in Shetland, we reckoned that a polycrub would be likely to withstand the wind.

We dont have any direct sun for 6 weeks or so through the winter , with the sun reappearing over the hill and hitting the house at the end of January .  So the best place to put it would be furthest north on our land that  it  can reasonably go .

So its going on a bit of the hardstanding out the back .
But there are a several problems.

1. Well-compacted hardcore .

Initially it was going to be raised beds , but on further consideration it would be more flexible to  put it on the soil. So the hardcore has to come up . And i think we might need some topsoil . There some being removed from the  new hospital site . I wonder what they are doing with the removed topsoil ?

2. A slope

The construction guide is for a level site. We have a  slope. When I measure it  there is approximately 300mm drop along the northerly edge . So the northeast corner would be  300 mm  lower than the  northwest corner ( the highest point) . And there is a slope north to south, and the southeast corner will be a further 150 mm lower.


3. bedrock

The installation guide says put the  supporting posts in 600mm.  Digging down, we hit bedrock after 200-450 mm.

So the first thing is to see if we can drill a hole.  Peter the Fencer  arranged for some help

and then to drill some holes

 And it wasn't just in one spot

And at the shallowest point ,the bedrock is about 15 cm down.

The solution  for both the slope and the depth of the holes , is shuttering the posts . Which is what they do in Shetland whne erecting these things and the holes for the posts can't go deep enough

So the gap between the posts is filled with concrete , supporting the posts and getting the whole things level.  Hence the cement mixer

 Its a bit sheltered where the polycrub is going . We've measured  63 mph 

Altogether I reckon I could need  0.7 cu metres of concrete . ive been told  by a retired engineer that a cubic metre of concrete weight 2.5 t. So  altogther I'll be putting down 1.75t of concrete.

That should hold it .

But i might just run this past a structural engineer for my own peace of mind.