Greenhouse question

Thanos

Hi folks,

I am going to buy a "real" greenhouse (have had a few of those small ones with plastic covers) and have decided on most things about it apart from the glass/polycarbonate.

I have kids but they are older so them running into it is not a concern for me.

what are the other pros and cons for different panels?

Thanks in advance.

fryup

i wouldn't dismiss the polycarbonate ones, i put up this one a year and a half ago and its still standing strong no issues during stormy weather

imo the key is to have a good level foundation and base and if possible in a sheltered area, i used a timber frame base that i fixed to the ground and built the green house on top of it, (bear in mind its a two man job and putting on the gable end above the door can be a right pain:( )

just take your time and read the instructions carefully, took me about 4-5 days...and also the fact the panels have a frosted effect i've had no bird strikes compared to clear panels

Sonnenblumen

There are greenhouses and there are Greenhouses

pinch

I bought a greenhouse 4 years ago and have only one regret. I should have go a bigger one. I bought on 8 feet long, built a base of two layers of redbricks, this means i have to step over on the way in the door but that is no bother. I bought the shatter glass which added around 400 euros to the price but is was worth it for peace of mind.
I also regret not buying the automatic top window openers for hot days as it often goes up to 40degrees when the sun shines. I am growing grapes along with all the usual such as toms and cucs.

robbie checker

In my opinion the polycarbonate is a no go on my site anyway. Given the storms we've had the last few years, it would have been blown away many times. It is the glass which holds the greenhouse down as the frame is quite light on the Elite Belmont glasshouse I purchased from Morris and you need the glass to weigh it down.

Sonnenblumen

Sonnenblumen wrote: »

There are greenhouses and there are Greenhouses

Key selection crieteria when choosing a Greenhouse:

Size matters - usually people buy too small. select a size and buy next one up (at least)

Ventilation is very important and key for growing and maintaining healthy plants. This is where many greenhouses let their owners down with inadequate ventilation that stifles growth and allows disease to breed. Choose a structure with full length ridge ventilation, which opens automatically (no electric power required) once temperatures reaches 20 Celsius and remaining open so long as temp remains above this level. As soon as temps drop below 20 degrees, the vents will close again.

Toughened Glass - safety first!

Staging & Shelving - make the internal space more functional, ergonomic and efficient!

Quality counts - a well designed and appealing structure is the best investment to make. A quality well designed and made Greenhouse is a joy to use, practical and makes an appealing garden feature.

Unlike inferior alternatives, a good greenhouse is not only the perfect place for plants but also for people too!

syklops

Ive helped my dad build all his greenhouses in the last 20 years. Theres been a few, all but one destroyed in a storm coming off the atlantic. The current one has survived 5 winters, so hopefully this is the keeper. Having now been bitten by the growing bug Im looking forward to owning my own home so I can build my own greenhouse. Some suggestions:

- Concrete foundations and concrete flooring.
- Plumb it - its handy having a water source for watering and cleaning. My dads new one even has a sink as well as an automated watering system.
- Size, make it as big as you can afford. Its not a man shed but a seat and a desk or bench to work on makes it all the more comfortable.
- Sparks! Give it power. You might want a light or a heater for the winter.
- Air, as another poster said ventilation is important to stop it becoming a damp musty mess, but make sure whatever vent it has is not the sort of thing that will get ripped off by a sharp gust and then threaten the integrity of the structure.

I'll post back if I think of anything else.

taxusbaccata

I just took the plunge and ordered a Janssen Helios 20x10 feet. Pricey but it will be our forever glass house.
To be constructed very soon. I looked at a few and this one seemed very solid and spacious with some nice extras - gutter rain collection, irrigation system, wide doors for wheel barrow etc.

looksee

From what I have seen of other people's greenhouses (I don't have one) the polycarbonate panes can flex enough to come out of the frames in a strong wind.

fryup

^^^^^^^^^^^

not if you install them properly, mine haven't.....the key is not to have the greenhouse too exposed if possible

Calahonda52

I know this thread is a few years old but its still very relevant to my question was well as containing good advice from SB above in post 6

herself wants a GH and the debate is whether all glasshouses work best with a concrete floor and pots or is the concrete floor unnecessary.?
Thanks as always.

uck51js9zml2yt

Calahonda52 wrote: »

I know this thread is a few years old but its still very relevant to my question was well as containing good advice from SB above in post 6

herself wants a GH and the debate is whether all glasshouses work best with a concrete floor and pots or is the concrete floor unnecessary.?
Thanks as always.

Just use sleepers as a base for the frame on level clay.

Reckless Abandonment

Just an idea. I'm currently turning an old conservatory into a greenhouse. Got one on adverts a while back. just finished building walls to support it. Hope to have it finished in the next week or so.

rolion

The thinbk about greenehouses is ... compromise between space and the number of plants/vegies that you can go as a healthy way.

I build a decent size greenhouse myself but,dunno how to say it, for me,is very easy to overgrown everything and lose lots of greenery due to small crowded space. I need to have lots of vegies but to respect each others space and intervals and ventilation and light and ... sharing same soil.

So,how small a greenhouse must be to satisfy your greenery appetite !?

Calahonda52

Any thoughts on concrete base or not?

rolion

Well,is a tricky one.


Concrete floor may limit you to using only pots or a certain deepness of the beds / soil.
Some plants needs deep soil for their valuable roots to reach the food and water.

Non concrete floor,means you can go as deep you like usign the current ground type but you ened to protect it somehow against the elements of natural organic world:bugs,weeds and others.

Also,you will need to think of the external protection,structure,wind and heavy rain.
On what those walls will be fitted in to,ground / soil will may not be enough.

My GH is ground fitted and no concrete.
Used top soil down to 60cm with piping and protection membrane.
Timber build and plastic cover (really want to use glass but later maybe,stage 3)

What do you have in mind in relation to soil,plants type and raised beds ?
What is the size of the plot,real size for the GH structure ?

Enjoy it

Reckless Abandonment

Calahonda52 wrote: »

Any thoughts on concrete base or not?

I have 75% concrete floor, definitely recommend concrete base to support the frame of the greenhouse. I left room to plant directly into the ground inside if needed.

Also in the market for a greenhouse.
We really want a dwarf wall though.
Anyone got one?
2k budget but could probably stretch it a bit

Calahonda52

Reckless Abandonment wrote: »

I have 75% concrete floor, definitely recommend concrete base to support the frame of the greenhouse. I left room to plant directly into the ground inside if needed.

Thanks, how big is the GH?

rolion wrote: »

Well,is a tricky one.


Concrete floor may limit you to using only pots or a certain deepness of the beds / soil.
Some plants needs deep soil for their valuable roots to reach the food and water.

Non concrete floor,means you can go as deep you like usign the current ground type but you ened to protect it somehow against the elements of natural organic world:bugs,weeds and others.

Also,you will need to think of the external protection,structure,wind and heavy rain.
On what those walls will be fitted in to,ground / soil will may not be enough.

My GH is ground fitted and no concrete.
Used top soil down to 60cm with piping and protection membrane.
Timber build and plastic cover (really want to use glass but later maybe,stage 3)

What do you have in mind in relation to soil,plants type and raised beds ?
What is the size of the plot,real size for the GH structure ?

Enjoy it

have to ask the boss!

BrownFinger wrote: »

Also in the market for a greenhouse.
We really want a dwarf wall though.
Anyone got one?
2k budget but could probably stretch it a bit

Why DW?

uck51js9zml2yt

What are people using as a base for the frame.
Have to put up s polycarbobate GH..

fryup

^^^^^^^^^^^^^

timber frame to the L x W of the greenhouse

cut four lengths of timber and fix each corner with a metal bracket

Drill & counter-bore several holes within frame and then hammer the longest bolts you can get your hands on through them so as to fix frame to the ground.

*beforehand make sure your foundation is nice & flat and not in too an exposed area,

*also use treated timber for frame

uck51js9zml2yt

fryup wrote: »

^^^^^^^^^^^^^

timber frame to the L x W of the greenhouse

cut four lengths of timber and fix each corner with a metal bracket

Drill & counter-bore several holes within frame and then hammer the longest bolts you can get your hands on through them so as to fix frame to the ground.

*beforehand make sure your foundation is nice & flat and not in too an exposed area,

*also use treated timber for frame

Is it worth using bricks under the wood to keep it off the damp soil.

Reckless Abandonment

Calahonda52 wrote: »

Thanks, how big is the GH?
3.5m by 4.5m

fryup

Mara Hissing Shellfish wrote: »

Is it worth using bricks under the wood to keep it off the damp soil.

nah, as long as the timber lengths are treated you'll be fine

iamtony

Calahonda52 wrote: »

Any thoughts on concrete base or not?

Concrete would be ideal. For my own green house I cemented the frame into the ground in the 4 corners using post cement mix. You just empty the bag into the hole you dig and pour in water. Then I took out the top layer of soil/grass and put down a weed barrier and put a ton of stones in it. Cost about 50 quid. Still standing about 8 years later.
Only issues I have is some grass grows through the stones because I spill some compost every now and then.

uck51js9zml2yt

iamtony wrote: »

Concrete would be ideal. For my own green house I cemented the frame into the ground in the 4 corners using post cement mix. You just empty the bag into the hole you dig and pour in water. Then I took out the top layer of soil/grass and put down a weed barrier and put a ton of stones in it. Cost about 50 quid. Still standing about 8 years later.
Only issues I have is some grass grows through the stones because I spill some compost every now and then.

How did this work?
Were the holes the same level?
Did you use wood in between?

iamtony

Mara Hissing Shellfish wrote: »

How did this work?
Were the holes the same level?
Did you use wood in between?

I just dug 4 holes, one at each corner and the frame had legs that went into the holes. Then I emptied a bag of post cement mix in each hole and levelled the frame and then added the water and left it to set. Next day added the gravel and built the greenhouse on top.

Calahonda52

Some great ideas here, thank you..
so, thinking about this over night, am toying with the idea of building my own from scratch.
Have no issue with the carpentry, which is just first fix standard.
The base is a separate issue, assume for now we have a level base to fix it to above the moisture level
The idea is using tanilised timber for the frame and sheets of polycarbonate outside that.
ventilation will be through the apex at each end.

Couple of initial pinch points:
How to access roof for sheeting it with polycarbonate.
Getting the various portal frame connecting pieces: e.g. haunch and apex as per the attached picture..
..
Would welcome any experience etc in this area.


ATTACHMENT IS JUST FOR IDEAS ON THE DIFFERENT JOINTS

fryup

^^^^^^^^^^^^

jeepers! that looks like more a garage than a greenhouse...what are the dimensions?

Calahonda52

Calahonda52 wrote: »

Thanks, how big is the GH?




Why DW?

Much nicer looking basically.

Lumen

I wouldn't worry about access, although the sheeting will be a bit slippy you can sling a strap over the apex and hang off it.

Is that diagram indicative of the pitch?

Low pitch and high apex braces means the apex braces are going to be under a lot of tension (compared to a more normal pitch with triangulation at top of walls), that design seems to be for a metal construction rather than timber. Do you really need that much uninterrupted clear space above head height? But in any case, threaded rod, washers and bolts ought to do it (maybe some else has a better suggestion).

Or, given how incredibly light multiwall polycarbonate is, could you maybe get away with a ridge beam design? Go thicker on the polycarbonate for better insulation, and then it'll be more rigid so will need lighter roof members. I used a 300mm x 150mm douglas fir ridge beam for a 5m clear span, and my spreadsheet said that would cope with a 1500kg roof structure. If you keep the roof MUCH lighter, you can bring the ridge beam dimensions down to standard lumber sizes (cheaper and safer to work with).

25mm multiwall polycarbonate is 3.4kg/m2, so 20sqm of roof would only be 70kg (light transmission ~50%).
16mm multiwall polycarbonate is 2.6kg/m2, so 20sqm of roof would only be 52kg (light transmission ~75%).

https://www.twinfix.co.uk/products/multiwall-polycarbonate/25mm-multiwall-polycarbonate

So I reckon go the Colin Chapman route: simplify, then add lightness.

Reckless Abandonment

Block work so far. As I'm rebuilding and old conservatory have to build back wall. Luckily will have double doors on both ends and windows will open on all sides. Only thing I dont have yet is roof vents. Added some vent to the back wall for now.

Calahonda52

Lumen wrote: »

I wouldn't worry about access, although the sheeting will be a bit slippy you can sling a strap over the apex and hang off it.

Is that diagram indicative of the pitch?

Low pitch and high apex braces means the apex braces are going to be under a lot of tension (compared to a more normal pitch with triangulation at top of walls), that design seems to be for a metal construction rather than timber. Do you really need that much uninterrupted clear space above head height? But in any case, threaded rod, washers and bolts ought to do it (maybe some else has a better suggestion).

Or, given how incredibly light multiwall polycarbonate is, could you maybe get away with a ridge beam design? Go thicker on the polycarbonate for better insulation, and then it'll be more rigid so will need lighter roof members. I used a 300mm x 150mm douglas fir ridge beam for a 5m clear span, and my spreadsheet said that would cope with a 1500kg roof structure. If you keep the roof MUCH lighter, you can bring the ridge beam dimensions down to standard lumber sizes (cheaper and safer to work with).

25mm multiwall polycarbonate is 3.4kg/m2, so 20sqm of roof would only be 70kg (light transmission ~50%).
16mm multiwall polycarbonate is 2.6kg/m2, so 20sqm of roof would only be 52kg (light transmission ~75%).

https://www.twinfix.co.uk/products/multiwall-polycarbonate/25mm-multiwall-polycarbonate

So I reckon go the Colin Chapman route: simplify, then add lightness.

Thanks Lumen, much appreciated, the picture was just for the names of the joints etc so it will be a more conventional A roof

Interesting the light transmission numbers for the different material.

What would normal glass be?

Does reduced light transmission equate to reduced solar gain?

SHMBO not gone on the polycarbonate so looking at glass for two sides that don't face walls, so you can see in/out.

Carey Glass are down the road so will go down to then for a look see on glass

Lumen

From memory, normal glass is about 90% transmittance per layer.

The total energy transmittance figures for the multiwall polycarbonate are also in that link I posted.

Problem with glass is weight and fragility. I remember someone at Russborough House saying that they had to replace panes in their glasshouse every winter, and that was sheltered in the walled garden.

Also, unless its double glazed the heat retention will be appalling, but if you don't care about that you can use single layer polycarbonate which will look less industrial than the multiwall. Also, I think there's a company in north Dublin that coats polycarbonate to improve scratch resistance.

Did you put in a damp proof course?

rolion

Hi,

Nice to see people interested in the area...
Ive built my own DIY grenehouse couple of years back. Link H E R E

Is very important to get things right and set from beginning,otherwise you will work as a "slave" adapting and improving and cleaning.Never ever ending work around it...

Very important is to get your wife / husband approval adn support.On my own,i will not have been able to get here,today,as despite looking small,is a very hard thing to keep it working,it has to be clean as a hospital,workign as you are living in there and constantly monitored and adapted...too much heat for tomatoes and they gone,too much cold and the flowers have dropped,too much or too less water has its own troubles.
Not lastly,plan how you will defeat the small nasty bugs...you leave the salad green and healthy today and in the morning half is gone.
Same with the trees,leafs healthy and green,in few days they are ondulated,dried and brown / or in half the size.

But the answer to all these stays in hard work,enjoyable results and hit and miss experiments until you get the right satisfaction.

Either way,enjoy the journey,the adventure in getting built and populate it with the first greenie wonders seeds /roots / plants.

Few photos taken few days ago,still finding something to work around,to keep your mind occupied.
Got some SONOFF devices and i hope to be able to automate most of the things in there.Also,installing a second monitoring and reporting/logging temperature system for checking how the temperature/humidity of weather, fans and geo works over a period of time. I had over 40 degrees in there last summer and i hardly try to avoid it this year...

uck51js9zml2yt

rolion wrote: »

Hi,

Nice to see people interested in the area...
Ive built my own DIY grenehouse couple of years back. Link H E R E

Is very important to get things right and set from beginning,otherwise you will work as a "slave" adapting and improving and cleaning.Never ever ending work around it...

Very important is to get your wife / husband approval adn support.On my own,i will not have been able to get here,today,as despite looking small,is a very hard thing to keep it working,it has to be clean as a hospital,workign as you are living in there and constantly monitored and adapted...too much heat for tomatoes and they gone,too much cold and the flowers have dropped,too much or too less water has its own troubles.
Not lastly,plan how you will defeat the small nasty bugs...you leave the salad green and healthy today and in the morning half is gone.
Same with the trees,leafs healthy and green,in few days they are ondulated,dried and brown / or in half the size.

But the answer to all these stays in hard work,enjoyable results and hit and miss experiments until you get the right satisfaction.

Either way,enjoy the journey,the adventure in getting built and populate it with the first greenie wonders seeds /roots / plants.

Few photos taken few days ago,still finding something to work around,to keep your mind occupied.
Got some SONOFF devices and i hope to be able to automate most of the things in there.Also,installing a second monitoring and reporting/logging temperature system for checking how the temperature/humidity of weather, fans and geo works over a period of time. I had over 40 degrees in there last summer and i hardly try to avoid it this year...

What was the function of the pipes?

Calahonda52

Mara Hissing Shellfish wrote: »

What was the function of the pipes?

Read here
https://www.boards.ie/vbulletin/showthread.php?t=2057719469

uck51js9zml2yt

Calahonda52 wrote: »

Read here
https://www.boards.ie/vbulletin/showthread.php?t=2057719469

Read it and made no sense hence the question

Calahonda52

Mara Hissing Shellfish wrote: »

Read it and made no sense hence the question

On the bottom of the ground, installing 7 pieces of 110mm pipes that will connect to a central manifold of 160mm that will recirculate the air in the greenhouse, summer and winter.

Calahonda52

Thinking of building a normal portal frame in tanalised timber.

Will us ALu plate brackets for bracing and ss fixings

Roof it with polycarbonate, with gutters to collect rain water.
Then line the inside, including the rafters with polythene from here
https://www.thepolytunnelcompany.ie/cat/polythene

Ventilation through the gables at each end


A plus I see is that the timber will never get wet from condensation
A minus is that I wont be able to easily use collars to ease the pressure on the portal knee joint.
Any thoughts?

Zzippy

Calahonda52 wrote: »

Thinking of building a normal portal frame in tanalised timber.

Will us ALu plate brackets for bracing and ss fixings

Roof it with polycarbonate, with gutters to collect rain water.
Then line the inside, including the rafters with polythene from here
https://www.thepolytunnelcompany.ie/cat/polythene

Ventilation through the gables at each end


A plus I see is that the timber will never get wet from condensation
A minus is that I wont be able to easily use collars to ease the pressure on the portal knee joint.
Any thoughts?

Are you roofing with polycarbonate and also putting polythene inside this? Seems like overkill. Would you not get a lot of condensation between the two?

Calahonda52

Zzippy wrote: »

Are you roofing with polycarbonate and also putting polythene inside this? Seems like overkill. Would you not get a lot of condensation between the two?

No it will be open at the eaves, and maybe at the apex: there are a few trees around so falling branches etc

Lumen

Would you even need tanalised timber if it's not going to get wet?

When I eventually get round to building a greenhouse I reckon I'll do this:

- "Ring beam" of untreated oak sleepers at ground level, on top of gravel for drainage.
- Four stud walls, using untreated CLS framing timber, screwed into the sleepers.
- Couple of cross members to stop wall spread, nailed through the top of the studs. I've always fancied using wire for this but I guess it might be a bit lethal if it snapped.
- Multiwall polycarbonate on the outside, tek screwed to the studs for racking strength and weather protection.
- Multiwall polycarbonate arc roof, tek screwed to the tops of the walls with a bit of overshoot into gutters.
- Maybe a couple of ground anchors to counter lift.

Calahonda52

It will get wet from the rain but dry off, not like if in the damp GH.
A few turnbuckles with 6mm plastic covered braided wire should do as your collars

rolion

Calahonda52 wrote: »

No it will be open at the eaves, and maybe at the apex: there are a few trees around so falling branches etc

Just to mention that you need proper ventilation,mechanical better,subject to size and build of the unit.
As today, my GH ground level reached 32 degrees. Keep it like this for few days and you can say to plants good byeeeeee ...

Calahonda52

rolion wrote: »

Just to mention that you need proper ventilation,mechanical better,subject to size and build of the unit.
As today, my GH ground level reached 32 degrees. Keep it like this for few days and you can say to plants good byeeeeee ...

Thanks
My plan is to have the apex open at each end in hot weather

rolion

Calahonda52 wrote: »

Thinking of building a normal portal frame in tanalised timber.

Will us ALu plate brackets for bracing and ss fixings

Roof it with polycarbonate, with gutters to collect rain water.
Then line the inside, including the rafters with polythene from here
https://www.thepolytunnelcompany.ie/cat/polythene

Ventilation through the gables at each end


A plus I see is that the timber will never get wet from condensation
A minus is that I wont be able to easily use collars to ease the pressure on the portal knee joint.
Any thoughts?

Personal experience after 2 years with polythene.
It gets so "dirty" and steals the visibility of the greenhouse.
I will love to be able (afford) to replace the front (where visibility is at maximum) with clear acrylic 3-5mm or even glass, on the whole surface. Leave foil only on the sides,where not so visible to eyes.

Advantage is that i can see through while sipping a coffee in the garden major disadvantage is that light and rays direct coverage may affect the plants leefs...