On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download: http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

OK lets throw a curved Ball
Why put a door at an end, why not have the front as 2 or 3 removable
panels, that way you wont be trying to put a path down the length and
will have more growing area.

Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot becomes a serious problem, I will do some further cost benefit analysis.

I think the main thing to decide on before continuing is the design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some thought, I don't want to upset my neighbour by going too high above the fence so what I could do is raise the height to 170cm, and dig down 30cm into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the greenhouse but I guess if I am going to go through the effort I might as well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in front of the plot, It is West facing and gets sun approx 12:30 to 18:00

Alternatively I could buy a bunch of these:

Aluminium Extruded Angle 20mm x 20mm x 1000mm Offcuts To Clear | eBay

I would just have to figure out another use for the garage full of timber beams I've been accumulating over the past few months.

Well yeah that was kind of my original idea, except I was picturing them opening upwards on hinges like a growbox.

Somebody raised the point that in winter (if I was to use it in winter) opening the panels would release a lot of the warmth, but I am with you on this one.

This would probably rule out the digging a deeper foundation to increase the height idea, it would be quite a big step down....but maybe I could strategically place steps on the inside to step onto.

This wood rotting business is putting me off, what do you think of the aluminium idea? Looks like I could pick up some aluminium beams quite cheap. I wouldn't have a clue how to build with the stuff but it can't be brain surgery

On 23/06/2013 19:29, Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high above the
fence so what I could do is raise the height to 170cm, and dig down 30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to 18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download: http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarbm and line it in the winter
with large bubble film.

On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download: http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

BRINGING THE TOPIC BACK

On 23/06/2013 21:50, David Hill wrote: On 23/06/2013 19:29,
Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high above the
fence so what I could do is raise the height to 170cm, and dig down 30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to 18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarb and line it in the winter
with large bubble film.

On 23/06/2013 21:55, David Hill wrote:
On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

BRINGING THE TOPIC BACK

On 23/06/2013 21:50, David Hill wrote: On 23/06/2013 19:29,
Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit
analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high above the
fence so what I could do is raise the height to 170cm, and dig down
30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I
might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to 18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarb and line it in the winter
with large bubble film.

If you are thinking about getting a flimsy then have a look at
http://www.robertdyas.co.uk/P~149009~Walk-In-Greenhouse
http://www.robertdyas.co.uk/P~155280...-In-Greenhouse
Spend £40 or more for free delivery
Use promotional code DD10 if you spend over £50 and get £10 off before
30th June

On 23/06/2013 21:55, David Hill wrote:
On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

BRINGING THE TOPIC BACK

On 23/06/2013 21:50, David Hill wrote: On 23/06/2013 19:29,
Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit
analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high above the
fence so what I could do is raise the height to 170cm, and dig down
30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I
might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to 18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarb and line it in the winter
with large bubble film.




Sorry to break in on David's post, but this is the first time I've seen
the photograph and made sense of the site and the quest for your greenhouse.

In your position, I would stick to buying an off-the-shelf
aluminium/poly greenhouse, as you first thought. It would have
(presumably) some sort of guarantee *and* be a whole lot more attractive
for you and your neighbours. You could then choose to supplement it
with homemade coldframes or mini-greenhouses to suit your own
requirements. These would free up a lot of space in the main greenhouse
when seedlings/plants reached hardening off stage and still give you an
interesting project. The height would be less of an issue with
neighbours if the structure was traditional and halfway decent to look at.

--
Spider
from high ground in SE London
gardening on clay

On Sun, 23 Jun 2013 20:29:56 +0200, Howzit_China
wrote:


Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high above the
fence so what I could do is raise the height to 170cm, and dig down 30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to 18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download: http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+

OK. You want to fit something into something. And to do that you want
to make a lot of work for yourself.

First question. Think carefully again what you want to do with
whatever it is you end up with. The fence supports are on your side so
you might assume that the fence is "yours". Check the deeds. If it is
then you can use it as the "back" of something. However if it is a
"joint" fence then you cannot without your neighbours' permission. In
any event, that fence will have a lifespan and if not treated that
lifespan will be shorter! If the posts are simply concreted into the
ground, count 10 years (max) from the time the fence was built to the
time the whole structure needs replacing.

Essentially, don't attach anything to the fence.

Look at something like this:

http://www.gardenbuildingsdirect.co....zed-Greenhouse

Will probably work out the same cost at the end of the day. Is easy to
assemble, place, shift when needed. The shelves can be used or
removed. So you can, say, use it for tomatoes or smaller stuff. There
are other variants around if you look. I have two similar things which
serve happily as over-wintering locations for tender stuff, growing on
locations for summer bedding, tomato growing, autumn bedding growing
....... Damned useful for storing dirty pots until I get round to
washing them too!


--
Cheers, Jake
=======================================
URGling from the other end of Swansea Bay where it's
unusually just like Dave's end, only better

On 23/06/2013 22:42, Spider wrote:
On 23/06/2013 21:55, David Hill wrote:
On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

BRINGING THE TOPIC BACK

On 23/06/2013 21:50, David Hill wrote: On 23/06/2013 19:29,
Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit
analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high
above the
fence so what I could do is raise the height to 170cm, and dig down
30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I
might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to
18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarb and line it in the winter
with large bubble film.




Sorry to break in on David's post, but this is the first time I've seen
the photograph and made sense of the site and the quest for your
greenhouse.

In your position, I would stick to buying an off-the-shelf
aluminium/poly greenhouse, as you first thought. It would have
(presumably) some sort of guarantee *and* be a whole lot more attractive
for you and your neighbours. You could then choose to supplement it
with homemade coldframes or mini-greenhouses to suit your own
requirements. These would free up a lot of space in the main greenhouse
when seedlings/plants reached hardening off stage and still give you an
interesting project. The height would be less of an issue with
neighbours if the structure was traditional and halfway decent to look at.

You're not breaking in.

All valid points

Just to clarify I had no intention of using the garden fence as part of the structure and would treat the wood before building the greenhouse. But yes that's a good point re the lifespan of the fence.

I am not really keen on the flimsy greenhouses, I think they look nasty.

All things considered I am probably better off getting something like the below:

Greenhouse 6 x 4 Polycarbonate Palram with Base | eBay

If I built something myself I would have much more space but I will just have to get
creative with my use of space.

Well I am glad I posted here, looks like I saved myself a lot of grief. Thanks for all the advice

On 24/06/2013 06:29, Howzit_China wrote:
All valid points

Just to clarify I had no intention of using the garden fence as part of
the structure and would treat the wood before building the greenhouse.
But yes that's a good point re the lifespan of the fence.

I am not really keen on the flimsy greenhouses, I think they look
nasty.

All things considered I am probably better off getting something like
the below:

'Greenhouse 6 x 4 Polycarbonate Palram with Base | eBay'
(http://tinyurl.com/ly865my)

If I built something myself I would have much more space but I will just
have to get
creative with my use of space.

Well I am glad I posted here, looks like I saved myself a lot of grief.
Thanks for all the advice


+-------------------------------------------------------------------+
+-------------------------------------------------------------------+



Have a look at these people
http://www.greenhousepeople.co.uk/clearance/

And if I am going to do that I might as well do as David says and tear down that wall, dig up the path and put in a 5 x 8 aluminium greenhouse.

I love it when a plan comes together.

On 22/06/2013 21:06, Howzit_China wrote:
Hi,

Looking for advice on a greenhouse I am looking to build in the sunniest
(relative) spot in my London garden.

My garden is West facing, the patch is South facing and gets sun from
12:30 to 18:00 (5.5 hours). Last summer I grew cherry tomatoes and
courgettes with fair success in this patch (birds got most of the cherry
toms tbh). I got a bunch or large tomatoes which didn't ripen in time
before the plants died at the end of the season (I didn't realise you
could ripen them indoors).

I want to build a greenhouse on this spot to increase my success rate
with tomatoes and other sun-lovers like peppers, cucumbers, squash and
pumpkin.

Originally I was going to buy a 4 x 6 foot aluminium greenhouse as the
space is awkwardly shaped and this is all I could find that would fit,
but then I thought if I design and build my own I could make better use
of the space and have a bigger greenhouse for the same money.

It's going to consist of a brick foundation (neighbours old driveway),
wooden frame (scrap liberated from skips), kitchen flooring for floor
(have this lying around) and a polycarbonate surface which I will need
to source. The whole structure will be covered in polycarbonate as I
don't want any wood exposed to the elements. See CAD drawing attached
(dimensions in mm). I've got my brother visiting in Sept and he has some
carpentry skills so planning to start work when he's over.

OK. But if I were you I would design it around the standard sizes of
twinwall polycarbonate sheet. BTW not sure I would bother to use
twinwall unless I was going to heat the greenhouse during winter.

Clear UV stabilised sheet would let more light in. Don't underestimate
the amount of ventilation that it will need (at the bottom and at the
top ridge) that will determine success or failure. Back wall on north
side if up against a fence could be made of anything.

What I couldn't figure out how to get across in the drawing with my
limited CAD skills is the panels A and B, I want the poly carbonate
sheet at B to be fixed in place, and A to open upwards on hinges, like a
grow box, except a 1.6 meter high grow box = ). This should give me good
access to all the plants as the space behind B will be quite large for
me to be able to duck under.

So questions:

1. What thickness polycarbonate and how many chambers is usual for
greenhouses?

I used 1cm UV stabilised. The thinner stuff flexes too easily although
it is fine for opening vents and much less likely to break if the wind
snatches it. Expect to have to do clever anchoring down of the sheets to
prevent them springing out. Unlike glass plastic bends very easily.

2. Does the pitch of the roof look OK? Is this important?

Initial reaction is make it square rather than triangular and a single
slope - preferably with enough headroom that you can work inside it!

Have an overhang, gutter provision for rainwater storage.

3. Will leaving the door open (A) occasionally be enough for ventilation
purposes?

Which is the door? I just see a space frame too small to stand up in.

You probably want a couple of thermostatic vents in the top (or along
the entire top ridge) and opening louvre panels on the side to let cool
air in. Most kit greenhouses have inadequate ventilation as supplied.

4. Does the design look practical?

Apart from the funny roof, awkward angle and dimensions requiring tricky
cuts and joints. Polycarbonate is fairly easy to work with a decent saw
if you take your time but you can make life much easier by designing
around the easily available stock sizes!

If using twinwall don't forget to use the sealing vent tape on the open
ends or it quickly fills up with dead insects and worse!

5. Is it worth the effort considering limited access to sunlight?

What direction is it facing?

I would consider making it at least 1.9m high and perhaps out of
aluminium if you intend to grow things that like plenty of water.

--
Regards,
Martin Brown

On 23/06/2013 23:25, David Hill wrote:
On 23/06/2013 22:42, Spider wrote:
On 23/06/2013 21:55, David Hill wrote:
On 23/06/2013 09:28, Howzit_China wrote:
Here's a quick drawing with the back adjusted to 2m.

The reason for the elaborate roof on my original drawing was to get
around what is happening in this drawing, which is that the roof angles
of the sides are different due to the different side widths so the
polycarbonate will need to twist slightly to fit the frame, but maybe
this will not be a problem.

Is polycarbonate strong enough that I could use one sheet for the
entire
roof and one for the front without any supports in the middle?


+-------------------------------------------------------------------+
|Filename: GreenHouseDesign3.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15650|
+-------------------------------------------------------------------+

BRINGING THE TOPIC BACK

On 23/06/2013 21:50, David Hill wrote: On 23/06/2013 19:29,
Howzit_China wrote:
Great thanks for all the responses.

Maybe I would be better off getting a blow away, especially if rot
becomes a serious problem, I will do some further cost benefit
analysis.


I think the main thing to decide on before continuing is the
design/dimensions before dealing with ventilation and rot prevention.

As two posters have mentioned the height I have been giving this some
thought, I don't want to upset my neighbour by going too high
above the
fence so what I could do is raise the height to 170cm, and dig down
30cm
into the ground giving a highest point of 200cm.

To be honest I didn't envisage myself spending too much time in the
greenhouse but I guess if I am going to go through the effort I
might as
well do it properly.

Photo of the plot attached, taken 20 mins ago. There is just lawn in
front of the plot, It is West facing and gets sun approx 12:30 to
18:00


+-------------------------------------------------------------------+
|Filename: Hounslow-20130623-00166.jpg |
|Download:
http://www.gardenbanter.co.uk/attachment.php?attachmentid=15657|
+-------------------------------------------------------------------+



Having seen the picture I fail to see why you want to make it such a
problem, and so much more work for yourself.
Keep to a regular shape and move the path.
You could even remove the screen block wall and extend the present
conservatory/ structure another 6ft or so along the fence, you could
use the same small profile plastic sheeting that you now have on the
existing roof, Much cheaper than polycarb and line it in the winter
with large bubble film.




Sorry to break in on David's post, but this is the first time I've seen
the photograph and made sense of the site and the quest for your
greenhouse.

In your position, I would stick to buying an off-the-shelf
aluminium/poly greenhouse, as you first thought. It would have
(presumably) some sort of guarantee *and* be a whole lot more attractive
for you and your neighbours. You could then choose to supplement it
with homemade coldframes or mini-greenhouses to suit your own
requirements. These would free up a lot of space in the main greenhouse
when seedlings/plants reached hardening off stage and still give you an
interesting project. The height would be less of an issue with
neighbours if the structure was traditional and halfway decent to look
at.

You're not breaking in.



Thanks for saying so.

--
Spider
from high ground in SE London
gardening on clay