So.. the digger is booked for the building of a climate-battery greenhouse.. and it's terrifying! The plan has been on the cards for about 3 years.. but I've only just been brave enough (well, I'm not honestly convinced that I actually am brave enough). I couldn't get any builders interested in doing the work for me, so will be doing it myself (with some help from my nephew)- the plus side being it is cheaper!
So on September 10th the minidgger arrives to dig out the whole thing- it is only a small greenhouse at 6m by 2.6m, hopefully a depth of 1m (depending on how much clay we hit). The next day me and the nephew will be building pillars out of hollow blocks- getting them straight and level may be interesting, putting rebar in and filling the blocks with concrete.
Wait for it all to set, then put the insulation (4 inch polystyrene) in and backfill the outside. Put the plenums in (210L blue barrels), and the pipe (4inch perforated drainage pipe) and start to refill the hole- I've got about a tonne of brick and gravel to go in as well as the soil that will have been dug out. I've also got an ibc container to be undergroundwater storage.
The insulation and pillars will come up to ground level, and everything will be left to settle for a few months whilst I plan building the top half.
Even though I'm only doing half a greenhouse- I fear having a very expensive hole in the ground for months. I managed to renovate the house over 4 years without any stress.. yet I'm worried about the greenhouse.
It will be great when it is done, if it gets finished. I have grand plans for growing grape vines up the outside, having a hammock inside and being able to overwinter plants.
current building site:
Wish me luck! I hope we can do it in a week, and there's no reason it should take longer, other than every job you do yourself always takes longer than anticipated.
First step was to clear the site, had forgotten how much garden was under the brambles! There was a pile of bricks and a load of slabs laid down the side, all of which were removed. And lots of dead wood, my 'wildlife pile' which will be reinstated after building (sorry frogs). I covered the area where the soil will be dumped with some tarps to make it easier to dig up again, and protected the grass with some sheets of ply. Just waiting for the digger now- it comes on Saturday.
My 'help' (my nephew) has got a job (yay!) so now can't help me.. so I'll be building it on my own.. which should be interesting...
Day 2 and we put in concrete pads for the pillars to sit on, and I dug down further to sink an ibc to store water.
Day 3 and the pillars go in- hollow blocks with poured concrete. They're massive, but I can't bricklay so this is the fastest way for me to build pillars. I tried to get cardboard tubes to pour concrete piers, but they don't seem to exist here and cost more than the blocks.
And I start putting in the perforated tubing for the climate battery bit. The first blue barrel will be the input plenum, and you can see the first btis of insulation going in on the right hand side. You'll also notice that the digger knocked the neighbours fence down!
This is taking loads of effort because we ran out of room to store the spoil- so we're digging stuff out and heaping it into the middle of the hole.. where later on we end up digging it out again.
that's the second layer of pipes going in. Have backfilled on the outside so that getting around it is slightly less dangerous, and have put the neighbours fence back up! Bottom right in the photo are some white boxes- they're temperature sensors going in at all different depths inside and outside, to see if it works after all of this!
Got to go back to work tomorrow, so the rest has to wait for the weekend- I'll have some help then though!
Second and third layer of pipes in and buried! Lots of smashed bricks and rubble in this layer.
Any ideas on what to use to exclude rodents? I fear they'll eat through the Styrofoam. I was thinking of standing paving slabs up against the foam, but invariable they'd be gaps somewhere that mice may get in.
I still have tonnes of soil to shift.. not entirely sure where it is all going to go... rest of my raised beds may be getting more raised! It all take sup much more room out of the hole in the ground!
I wouldn't have thought they'd necessarily want to live in there, but have been reading horror stories of them using Styrofoam and rockwool insulation as nesting material!
The pipe system is screened with stainless steel insect mesh, so that's pretty secure (and the pipes in the ground are surround by gravel and rubble, so good luck digging).
I live in an suburban area, no readily available food sources so there aren't many rodents here. Loads of pet cats around as well, so I'm probably worrying about nothing. I know a mouse lives in the shed, and had a rat in a compost heap once (he did a lovely job of aerating it, but left after I turned the heap).
So... I still haven't finished the climate battery. The hole in the ground got sorted, but the big pile of leftover dirt hasn't been yet!
I fitted 4 layers of pipes in- those immediately above each other having different routes but all pipes being the same length.
My excuse is I'm 'waiting for it to settle'. Realistically.. it keeps raining and I'm a wuss, and my car broke down, and I just haven't got round to it yet.
It's cool to stand on the big pile of earth though- I can be nosy and see into the neighbours gardens, and take photos where you can actually see the garden layout.
I'll finish earth moving next weekend, honest. I've got some bulkbags to move the earth to- to store it until I make the raised beds inside the greenhouse. Building the top half of the greenhouse will not commence until next year when the weather improves, which gives me a few months to actually plan and design something!
I'm back to building the greenhouse! Finally! The base was built 18 months ago, this year I intend to try and build the top half!
When I built the base (I dug down 0.8m and put in 3 layers of 80mm perforated drain corrugated pipe, connected to 80 litre barrel 'manifolds', with 4inch eps insulation around) I sunk an ibc there (1m down) for water/heat storage. Unfortunatelly I didn't fill the plastic ibc container with water before filling in around it, and not surprisingly it cracked! No worries- I have another! So we raised the sunken one, to replace it with a new one... there's 15cm of water in the bottom of the ibc hole. This puts the water below my shcs system pipes (by a few cm).
There was no water when we dug the hole (in September 2016, until about January 2017 when it got filled in). I live on a huge hill and the groundwater is meant to be be some 27m below my garden. There is clay- a layer of it I didn't manage to get through at 1m deep! I can mostly empty the hole (with a bucket) but it fills back up (seeping from the clay- takes about an hour to refill)
Does it matter that this hole is flooded? If yes.. what can i do about it? If the water is moving I guess it will take my heat away with it. Any solution has to just involve handtools!
Having done a bit more digging- removing all the soil/clay that has fallen into the hole when I was filling up the sides.. most of the water has now gone! I think it was full of water due to rainfall (I'd basically created a pond with clay sides!), rather than any groundwater. This should no longer be a problem once I actually build the greenhouse on top! But I have also tried to pierce holes in the clay base- I highly doubt I got through the clay (which is allegedly metres thick here)- but it makes me feel like I've done something!
Best of luck! I'm jealous of that digger - I'm digging out for my mike oehler inspired greenhouse using pick, shovel, sieve! Mostly sand and stone.
Where are you in Derbyshire, might be good to compare results once we are both done as I'm in Sheffield
The greenhouse build finally continues! Its only taken me two years...
Back wall will be a wooden frame, with osb- then insulation and wooden cladding on the outside.
the front wall (south facing) will be reused double glazed window units, with the west wall (up against the fence) a solid one, and the east wall mostly door! Roof to be polycarbonate 16mm triple wall, resting on a timber frame. Which is where I have some building-questions...
How do you find out what thickness of timber to make the roof from? There are span tables, but I can’t seem to work them out! They seem to assume heavy roof tiles (as are standard here), not light polycarbonate sheets. I want to use as little timber as possible so I don’t block light, but I also don’t want the roof to collapse!
A beautiful picture- with some labeling to ensure I have terminology right:
I'd like to use a 6x2 piece of timber for the ridge beam, and 4x2 for the rafters- putting the rafters 1.2m apart. But I've no idea if this is safe! Other than putting it together and seeing how creaky it feels, any advice?
The roof projections are 1.8m (28 degrees) for the south facing saide, 0.8m (and 34 degrees) for the north facing side- so it isn’t a huge roof. The greenhouse itself is 2m wide, 4.8m long. I am in the UK- it rarely snows (and then only a few cms), and I’m in a sheltered position (no huge winds or heavy storms).
Looking good, and looking like a good amount of work too hehe. Thanks for sharing the build progress. Can I ask about the rafters and ridge beam dimensions as I hadn't heard of 4x2 nor 6x2? Is that inches?
Thanks for the reply, I suspected that to be the case.
Two items from my experience may be of help on that rafter and ridge beam system you are asking about: Condensation in the two greenhouses I've built and run caused the wood to mold and rot quite rapidly. In my latest greenhouse an earth-sheltered design I went with treated and then painted wood which still seems to get mold somehow. While 2x4s may be adequate for the load I have found that with the amount of work put into the greenhouse construction especially with your build, the small dimension lumber may be the weak link in the overall structure during its lifetime. I''m going to extend our greenhouse next year and may if I can find something like recycled plastic products such as they make for decking to use instead of wood. Just thinking out loud, as I can't find a reference to wood alternatives for DIY greenhouse rafters.
I think 2x4 rafters and a 2x6 ridge should be good enough given your snow load. Especially if they're actually 50cm by 100cm. In the US a 2x4 is actually 1.5" by 3.5".
"Hundreds of years from now it will not matter what my bank account was, the sort of house I lived in or the type of car I drove... But the world may be different because I did something so bafflingly crazy that it becomes a tourist destination"
Thanks for your comments! I shall go ahead and build my roof in those dimensions I think, if it doesn't seem hefty enough once built it would be easy enough to add another rather in (so they would be 1m apart)- I won't order the polycarbonate until the frame was up.
I'm hoping with the SCHS there would be less condensation... but I couldn't find a way of not using timber. I did look at the recycled plastic lumber, but most of it appears to be none-structural so I assumed I couldn't use it for rafters. And I couldn't find a self-supporting aluminium frame that would work with a peak and polycarbonate (could find them for glass roofs for conservatories, but not for polycarbonate).
As I was going to put big raised beds inside my greenhouse (0.5m tall)- I was looking at using the recycled plastic sheet material as protection between my insulation and the soil (to stop me putting a spade through the insulation)- but it is really hard to get hold of! I can order in full pallets but I don't want 50 sheets for over £1K!
You are most welcome and thank you for letting me add my opinion. I'm glad you looked into the recycled material where I couldn't. It now makes sense that a recycled plastic product couldn't match wood grain for strength.
Greenhouse is slooooowly being built! I now have most of a timber frame (still need an east-facing wall though)
Had troubles with the timber yard. First they 'ran into traffic' so couldn't deliver (my house is less than a mile from the yard, so that's some impressive traffic). Then they delivered the wrong stuff, twice. But oh well.
Need to buy some more materials- as in the plastic sheeting for the base, and the polycarbonate for the roof- just got to wait for payday!
I now have a whole timber frame structure, and a roof- 16mm polycarbonate with pvc glazing bars, I couldn't find a glazing bar for the peak- so just put flashband on to make it waterproof and intend to put some upside-down guttering on as a protective cover. I ended up with the polycarbonate being 800mm wide- that seemed enough wooden frame that it all seemed stable.
And this weekend the 'walls' went on- well the insulation of the walls- I've yet to do any of the cladding. Mostly 4 inches of polystyrene insulation board (half of which I found in a skip), some bits have 6 inch.
The inside will be clad in osb, the outside has roofing membrane on, and I'll see what I can scrounge for the cladding eventually. Got to get the structure sealed up next- finish insulating the small end walls, seal the front south wall to the roof, and fit the glass and doors back on. I do like the 'proper' door- it was an old pvc one someone was throwing away as the hinge was broken- it was £4 to buy a new hinge!