Building a lean to greenhouse

[danlightbulb]

Hi all,

Im building a back to wall greenhouse out of wood to bespoke dimensions approx 2.4m high at the back, 1.2m wide, 0.6m deep, and 1.8m high at the front. There will be opening doors at the front and an opening lid.

I have the main framing timber and 4mm twin wall polycarbonate sheeting for the panels. But Im not sure how to attach it. I was planning to use some quadrant beading pinned into the framing and sandwiching the sheets between that. But, its really adding to the cost. The framing timber (38x63mm) was £3.50 per 2.4m length and Im using about 8-9 lengths. The beading is a similar price and I'd need double that amount because of needing beading both sides of the polycarbonate sheets. Its a crazy price for a 6mm x 6mm strip of wood.

Does anyone have any other ideas for how I can secure the polycarbonate sheets to my framing?

Thanks

 

[danlightbulb]

Im using 4mm twin wall polycarbonate panels https://www.ebay.co.uk/itm/144812670260

 

[danlightbulb]

Can't really picture what you're describing

Im building something like this: https://www.buyshedsdirect.co.uk/5x...OZmFLaz8ewlNvINbGxvF190b92BZ6mcoaAtLAEALw_wcB

 

[danlightbulb]

@Welshman thanks for the pic.

I could do that but it would cover up all my framing and wouldn't look as nice I don't think. You've managed to still keep some of the top and bottom framing visible so it looks integral, but mine wouldn't look like that if I just surface mounted the panels.

Could you use a router to cut a groove into your framing and then slot the polycarbonate in?

Maybe, Ive never routed before so I'd have to buy one, and can it be done without a decent workbench and proper guides to keep the groove straight?

 

[danlightbulb]

This is my rough design so you can visualise. I wanted the polycarbonate sheets to sit within the framing i.e recessed within it, like a piece of glass would be.

 

[danlightbulb]

This is a £50 quid cold frame type thing off Amazon. They have grooved in the PC panels by the looks of it, so that's what I'd ideally like to do.



Can I do this with a basic £30 router and what bit would I need to cut a 5mm wide by 5mm deep groove?

 

[danlightbulb]

If you want to frame them inside you need to router out 5-10mm all round and insert the panels then put something in to fill the gaps to sandwich the panels in place. At least partially.
You need a fairly decent step, or they may pop out however.

Do you mean a rebate?

I'd prefer to do a groove in the centre of the framing timber, rather than a rebate at the edge. I can then slide in the PC panels from the top before securing the top framing piece in place.

Like this I suppose?

The groove would need to be cut along the entire length of all my frame timbers. And when I make the doors, the groove cut along the inside frame of all the door timbers too.

Perhaps 5mm isn't deep enough and I should go 10mm deep for extra strength? This could also give me enough room to drive some securing screws in as well from the inside.

 

[danlightbulb]

Routers quite expensive aren't they. Seems to be at least £70 for a corded palm router. £200 if I wanted a cordless Dewalt one to go with my other tools.

Would a full size router be too big? They are cheaper.

 

[danlightbulb]

Sandwich it between 2 timbers, e.g battens.

That's what I was planning to do with the quadrant beading, but it's too expensive for what it is and how much I need.

 

[danlightbulb]

What do you mean 2x1 battens? Inches or cm? And how are you attaching these to the framing structure?

 

[danlightbulb]

I just used normal timber, no fancy beading when I did mine. I even used normal cheap timber to do my wooden glass one I made, just put some clear silicone between glass and wood.

Sorry what do you mean? I am using normal timber for the framing. But I somehow need to attach the polycarbonate panels.

 

[danlightbulb]

I take it you are using Snap Joiners for the sheets and if so I would suggest using Twin Wall fixings.

Watch this video and save money + time

Thanks but that's not suitable method for my application. He is surface mounting the panels on top of his framing, I need to recess mine within my framing.

I won't have need for joiners, my structure is exactly 1 panel deep. The panels will need to be 'within' the structure like in this Amazon example:

https://www.amazon.co.uk/TANGZON-Greenhouse-Transparent-Polycarbonate-Vegetables/dp/B0B63S79Y2/ref=mp_s_a_1_7?crid=2AL99BGEB8E00&dib=eyJ2IjoiMSJ9.R1xuiF8kJTziA1X_9OZe13lFHXBdfduFh3xrJVEGduW7ycIcj3RfG499V8GpVqSixti21PhZCx8QNaqGAs2HK2EoqWLLQSYu85c36tjaeXFG27s6hFpMGp0UFRJw4ZVgYNRYFB2ckIPpnm0XBdqu3uMmE8Zf9uCOtKO7EBDltCmo2RzCG32znAU_chvWSW4soVRZHeH3RZS7ULndTqBkyA.yj9eMS0nls8xtuIsQ7yeZ0H71Woc3LPdrPe71mjvc64&dib_tag=se&keywords=cold+frame&qid=1713507725&sprefix=cold+frame%2Caps%2C81&sr=8-7

 

[danlightbulb]

A visual representation of what I mean. Then the panels go into those.

Yes I get you but that's why I was originally planning to use quadrant beading or just some stripwood to essentially provide a rebate for the panels to sit against.

Your idea of using 10x38mm stripwood is the same but that's way too big. My framing is 38x63 CLS from Wickes because it was the best value per m. Other sawn timber dimensions were a lot more expensive.

I was only originally planning to use 6mm X 6mm quadrant or square stripwood, or maybe 10mm X 10mm. But it's £3 a length and I'd need 10-15 lengths of it at least, in order to sandwich the panels.

Twin Wall fixings and flashing tape.

Keep it Simple......

I don't want to surface mount the panels it won't look as nice. This isn't a 2 bit structure I'm trying to build it well.

 

[danlightbulb]

Essentially you build 2 frames with the glass in the middle, also this way gives you support for putting shelves in within the frame. Its very simple though, and cheap. But buying in Wickes is going to increase costs a lot. Surprised you chose CLS for outside, pressure treated timbers would have been better.

If you're trying to do it cheap just do what wleshman showed you above, it looks better than your idea of quadrant beading.

How would glass have been mounted in a wooden greenhouse? Beading.

I chose CLS because I can apply wood preserver and stain myself. It was twice as much at least to buy sawn treated timber. But whether I bought CLS or pressure treated timber I'd still have had the same problem with how to mount the panels.

Im accused of over complicating it when all I'm trying to do is replicate what you can get for £60 on Amazon...those have inset panels not surface mounted ones.

The reason I'm building it myself is because I need it to fit the space I have available.

 

[danlightbulb]

Removed as I am obviously wasting my time here.

Yes because your advice was crap.

 

[danlightbulb]

Mine is not. Its a mixture of routed channels and profiled timbers specially designed.

So that's what I need to do then.

 

[danlightbulb]

Suggested username change: Dandimbulb

Good luck in your quest to polish a turd and may you learn to accept advice from those that know what they are doing, have done it and spend their time banging their heads against walls when trying to help people like you.

I will not stoop as low as the comment above, but will suggest that the below has another gif with something about a sandwich in it

Look your advice was just not suitable for my application. You're telling me to surface mount my PC panels on my framing. It would look absolutely terrible with exposed edges top bottom and sides. If you've done it then put a picture up of your construction let's have a look at it.

The only way your solution would look half decent is to put additional cladding around the panels to provide a flush look. I'm not going to have room on my framing to fit extra cladding, it's only 38x63 timber CLS.

 

[danlightbulb]

I could list all the edges you can use to make it something Kew would be proud of, but alas you would probably question that and then ignore the advice.
Good luck in the building of your tiny tiny £300,000 plastic shed.

Lol can't accept he's given crap advice. Would be good advice for making a flat carport roof not a lean to greenhouse with opening doors.

 

[danlightbulb]

You will have to buy the right tools to do it as you want it i.e. the router.
If you don't want to do that then you have to do it in one of the ways that have already been suggested or buy the amazon one and modify it to fit your space

I'll have to buy the router or attempt to make a groove with a drill and hand chisel (drill a straight line of 6mm holes 10mm deep all the way along each piece of timber, and then use the chisel to clean it up and make it a continuous groove).

Not sure how long a manual approach would take. Obviously a router is better (more accurate, faster) and if I would use it again in future it might be worth having one. Not sure I will though.

Do you think a palm router or full size router is better for this? I will need to cut the groove in the centre of the 38mm edge of my timber, so not a lot of room for it to rest on.

 

[danlightbulb]

I know you don't want to hear it but
It really would be easier to make the frame, surface mount the polycarbonate and then use the 10mm x 38mm strips of wood Rueben Klang referenced to trim the sides and window frame design on the outside.
It would look almost the same from a foot away.

I think this is adding a lot of extra wood, cutting, screws/pins. I would have to frame the left side, right side, two front doors and the lid. Surely it's simpler and neater to groove the timbers and slot the panels in?