SCHS Greenhouse Build

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 underground water 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...

There is now a very large hole in the garden. Not quite a meter deep, only got to 80cm.



Lovely clay! Am saving some in bags to build a pizza oven or something out of.

Have found a brick wall going down the full depth.. maybe the remains of an old wartime bomb shelter? Doesn't seem to be a well wall.

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.

Charli Wilson wrote:- I fear having a very expensive hole in the ground for months.  

This made me laugh.  I have a hole 12ft (4 meter-ish?) x 12 ft x 17 ft deep that has been in my yard for 3 years.  I would like it to be a root cellar some day...

Slowly getting there...



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!

Looking great!
Thank you for sharing your efforts.
I think SCHS green houses have a lot of potential, and having a first hand report from a Permie is invaluable.

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 wonder if rodents will even want in.
Maybe a layer of concrete,spread or poured on the outside of the insulation.

Or back fill with broken glass....

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 digger was just a rental, it wasn't cheap but it sure beat me digging it all out by hand given the amount of bricks and concrete buried in the soil here!

And I'm in Alfreton- so not very far from Sheffield at all.

It occurs to me that you could place a pump at the deepest point and use that groundwater in the future.

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, great to see your progress!  Thanks for all the pictures and detailed descriptions!  Following and cheering you on!

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?
Brian  

Yes Brian that should be inches- bizarrely here the wood is actually metric but everyone refers to the nearest inch sizes! So 4x2 would be 4 inches by 2 inches, or actually 100mm by 50mm.

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.
Brian      

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".

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.
Brian

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!

Lots of progress in the past month!

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!

Lots more has been done! All the glass is in, all the walls are insulated and covered in roofing membrane- with batons ready for some cladding. At ground level I've protected the insulation with stokbord- which is recycled plastic sheeting. I probably won't do the cladding until next year now- its a bit wintery and cold now for such things. I'd like to get all the insulation covered up though- if nothing else than because my chickens try to eat it. I just need it to be dry enough t dig the stokboard in a bit.  



My latest question is about the floor inside. There will be a large raised bed all the way down the back wall, along the west wall, and halfway up the east wall. This leaves a path down the centre and 2/3 the width of the greenhouse by the door- that will be actual 'floor'. I feel I should insulate this- heat rising through the beds is all good, but not from the path. But how to insulate? Polystyrene would compress under slabs/gravel- and water wouldn't drain very well. A layer of vermiculite or leca (expanded clay pellets)- but again I'd need sturdier flooring on top of this, that would compress it. I could do sheet insulation and pour concrete- but that doesn't drain either and I don't think I'd DIY it very well! Any other ideas? What greenhouse floor do you prefer?

try 3/8 inch gravel

I can't remember Charli but is the perimeter of the foundation insulated?  And why is heat rising from the path a bad thing?  Seems like it would help keep things warm in the winter.

My floor is primarily going to be soil with mulch around the perennials.  The paths will start as dirt/soil but I hope to turn them into worm beds (like at CRIMPI).  So they'd be an area to put food scraps and they'd be covered with pallets to walk on.  Periodically I can lift up the pallets to feed the worms, harvest the castings or harvest the worms for the chickens.

The 'indoor pond' as I've been calling it is an unwanted amount of water collecting in the bottom of the ibc-hole dug into the floor of my greenhouse. I can bail it out- but when it rains it fills up again! It isn't below groundwater, but whilst we were digging out the greenhouse base we were walking around on the clay and polished it to a nice compacted water-holding surface. It is below my SCHS pipes, but only by about 10cm. If I poke holes in it, I think it would drain (or at the very least I would have done my best and can then give up on the idea!). How can I penetrate through the clay hardpan layer, given there's very limited room in there and it would be hand-tools only? I have tried digging/stabbing with a spade or building-fork- I'm not strong enough to get anything thorugh- it's like a few cms of squshy wet clay and water- then a solid clay base. Does a cordless drill and a really long masonry bit sound useful- or am I likely to just end up with polushed clay water-holding holes as well? Other tools i may try to use?
Or... is a few cm of water underneath an ibc full of water under a SCHS not really a problem, and I should stop whittering about it?

Mike Jay wrote:I can't remember Charli but is the perimeter of the foundation insulated?  And why is heat rising from the path a bad thing?  Seems like it would help keep things warm in the winter.

My floor is primarily going to be soil with mulch around the perennials.  The paths will start as dirt/soil but I hope to turn them into worm beds (like at CRIMPI).  So they'd be an area to put food scraps and they'd be covered with pallets to walk on.  Periodically I can lift up the pallets to feed the worms, harvest the castings or harvest the worms for the chickens.

Hi Mike,
Yes the perimeter is insulated to about 3 feet down. I think I figured that heat rising from the paths was somehow 'waste heat' and I'd prefer it to be either stored or go through the beds- am quite happy to be wrong though!

My paths need to be some form of hard-standing, due to a wheelchair needing to get over them. I like the idea of the CRIMPI worm beds but I think here they'd fill with slugs (my worm bin certainly does!)

Yeah, I guess it's hard to know if the heat rising is being lost from where you want it kept or if it's helping heat the greenhouse more often than not.  My inclination is that it's ok to let it leak up into the greenhouse.  Unless you're expecting the SCHS to store months of heat in the fall to get you through the winter.  Then I'd want to keep it down there until you actually need it.

Have you considered a temporary compost/vermiculture pile in the wet corner to loosen the soil for drainage?

Said clayey-hole is literally a meter cubed- a meter deep into the ground!



I don't think I'd ever be able to dig compost out-  a meter isn't quite big enough for me to wield a spade properly. And it being soggy at the bottom (though currently less soggy than that photo!) wouldn't make very pleasant compost.

I have been introduced to a post-holer as a tool, a coworker is lending me one to try in a week or so. Not sure how it will fair in the clay, but we shall see! And once I've dug a bit of w hole through the hardpan I'm hoping it will drain.. or then I'll give up on the idea and live with the puddle. It will hold way less water when loads of it is offset by the ibc plastic container (ideally full of water) that will reside in the hole- it whole thing won't fill up with water, only the bottom 20cm or so doesn't drain.

So my 'indoor pool' as I'm calling it- the big hole in the floor of the greenhouse that was meant to accept a similarly sized plastic container to hold water, is currently full of water with no plastic necessary! It is lovely clear water- the green crate you see is completely underwater at the moment.



It has been raining A LOT here. This isn't ground water, but just the clay soil being saturated. It starts to drain as soon as it stops raining. This has been dug for over 2 years now, this is the first time it has flooded anywhere near that deep (you can just see the bottom layer of blue shcs pipes on the top left of the photo)- usually it's just 10cm in the bottom. I've tried augering some holes in the bottom (about 2 ft deep)- it doesn't make it drain faster because the soil is so wet!

So my plan is just to leave it to drain. once drained I will sink the plastic container, and fill it with water. I'll have to remember to keep it full of water over winter (not a problem!) so that water coming out of the clay doesn't crush it or anything. I don't think there's anything more I can do (but I'm very glad I built the underground part of the greenhouse from stone and not wood!). This is holding back progress slightly in that I can't do much until I move that plastic container, but there's no real rush- I'll pick it up again in the spring!

Today I did much bailing-out of water, and finally got to sink the ibc!



Note to those who follow- save yourself months of effort by simply filling the tank with water before you bury it!

anyway it is now full, and the floor has been levelled slightly, and I've set some bits of wood out to mark roughly where my raised beds may go



Next question, what shall I make the raised beds from? I have loads of untreated timber, but I guess that won't last too long. anything else I shall have to buy/otherwise acquire. As the greenhouse is only 2m wide I really want the thinnest raised beds possible, but since I want the back one to be 0.5m tall it needs to be strong enough to hold the soil back.

My aim is to get some tomatoes in it by the summer!

Looking good Charli!

I had the same needs for my raised bed.  I had some cedar slabs from a sawmill that I used.  At the tallest end the bed is about 24".  I used cedar posts and connected the slabs to them on the dirt side of the posts.  They had some gaps so to make it pretty I added slabs to the path side to cover the gaps.  Those pieces aren't very structural.  So far it's held up well but it's only been a couple months.

We've recently had very awesome weather for Feb! I reckon it is all a ruse, and it'll soon snow. But in the meantime the greenhouse raised bed is built, and filled with compost and soil!



The beds are just made of some planks I already had, painted with some water-based shed paint (that I already had!). I've put plastic (damp proof course plastic) on the inside in the hope the planks will last longer.



Me trees are in! There's a fig, an apricot a hardy pomegranate and a peach. All trees that have survived a few years here outside anyway, but I'm hoping that by being inside I might get an actual crop. The bed on the right is 80cm tall, the one on the left 50cm- nice and deep and my other half (with the bad back) can garden a bit without having to do much in the way of bending. I had to move a hell of a lot of soil though!

Looking Awesome Charli!!!

Its been two and a half years... but so nearly there! It isn't even a big of particularly complex building, but had to wait for me to appropriate materials from the waste stream.

Gabion heat-sink wall


Front wall (interior)

Dead pleased that I got almost all of that plastic as offcuts from a local building site! And the silicone- turns out at the end of the day the builders just chuck the open tubes away- even when there's loads left.

Exterior


Beautiful cladding that you can't see because the clad sides face fences....


This weekend it needs some guttering and water collection adding on, and the last bit of detailing around the door doing. eventually it will also need flooring inside, but I'm going to leave that until I decide on what flooring I want. Most importantly- I shall be putting the hammock up! There is electricity to a fusebox inside, but I do need to add sockets and things, to actually get the fans for the heat sink working!