What is the most effective design for a garden covering?

[raymondo]

Hi helpful team. ... 

I need to construct a walk-in cover for my raised vege garden. (Pic attached). It's protection from the usual rabbits, vermin, dogs and birds. 

My problem is that the garden is backed by the South pole. The winds that sweep across the paddock shown are merciless.  I had originally considered 32 mm ag pipe hoops, but I don't think they would survive. Instead,  considering 90 mm treated pine poles, covered with bird netting. 

Looking for advice and suggestions. As always, minimum cost outlay is hoped for, but all is in vain if it doesn't stand up. 

The smaller pic (pintrest) looks neat but more expensive to construct. 

It's hard to find any construction examples for this on the net, as most of the ones I see when driving around, appear to be individually designed. 

Looking forward to any ideas.

thanks

ray

My three beds facing direct south.. An example of the desired outcome but probably not the most economical.

[EricL]

Hello @raymondo

Thank you for sharing your question about what is the most effective design for a garden covering in strong wind. 

I recommend using Treated Pine Outdoor Timber Framing 70 x 35mm to build a basic frame for the garden area. I suggest thinking of it as a sound investment in protecting your garden. A proper timber frame will provide you with long-term cover and can be used for many seasons. 

If we made a conservative estimate of using 30 linear meters of outdoor timber framing at the current price of $4.20 you would be spending $126 plus the timber screws and bird netting. If you manage to make a vegetable harvest in that strong wind then the frame would have served its purpose. Please note that the sizes indicated are for reference only. It's best to place the upright post into the ground and cement it in place.   

Let me tag our experienced members @tom_builds and @Adam_W for their recommendations.

If you need more advice or information, please let us know.

Eric

[Jason]

Hi @raymondo,

Have you seen these fantastic projects from Bunnings Workshop community members?

Garden shade hoop house by @Grub80 

Summer vegie patch project by @mandy111s111 

Hugelkultur raised garden beds by @TheSaltyreefer 

I hope they give you some ideas and inspiration, and that other Workshop members can provide their thoughts on your plans.

Jason

[raymondo]

Gidday Eric..

Thanks for the advice.

Your diagram is along the lines of what I need.  I'm thinking that  75mm treated pine poles would be stronger than  70x35s and cost about the same. 

What is the rule of thumb for how deep they need to go in the ground?

I'm also thinking of covering the south and west sides with polycarbonate sheet, to reduce wind, although this substantially adds to the cost.

The links posted by Jason were helpful also, in seeing what others have done.

ray

[EricL]

Hello @raymondo

The rule of thumb is 1/3 the length of the timber piece. But if you are putting in horizontal supporting pieces to support the post it may be less. Weight is also a factor in how deep the post is supposed to go. A typical fence post at 2400mm is supposed to be buried in at least 800mm, but we often see it being done at 500mm sometimes even less, hence you see these fences start to lean over time as the weight of the fence starts to drag the posts forward. 

Putting in polycarbonate sheeting will act like a sail and will put pressure on your timber posts. I recommend putting in knee braces at all the joints of the framework to give it extra rigidity. To provide even more support you can brace the frame with rope tensioners just like when you brace your tent when you go camping. 

Please keep us updated, I'm sure our members would be keen to see your garden covering.

If you need further assistance, please let us know.

Eric

[raymondo]

Thanks Eric..

All makes sense.

I certainly concur that the polycarbonates would act like a sail. It's a catch 22 situation, where we need wind protection as well and have to weigh up it's benefits against extra work and cost.

However, in our case, I think it will be worth it.

Will keep you updated.

cheers

ray

[raymondo]

Hi Eric...

Thanks for your suggestions so far...

I have determined the final overall size and what it will look like.

I just lack the skill in drafting the final structure between the corner posts.

I figure I'd need 100mm x 3 m pine poles in the corners.

At the south end and part west side, I'll install vertical Suntuf panels to reduce wind. I understand the need for the bracing as you have suggested.

I'm not sure about the framing for the rest of it. I'm thinking 45 x 70  (or 90) Pine  around the top, middle and bottom, but how far apart and what sizes for intermediate poles around the sides?

It's covered in Bird Netting (apart from the south and part west side)

Maybe two poles in the centre to prevent sagging. 

Apart from the wind, there's not a lot of stress on it. 

It's wider all round to allow wheelbarrow access.

Not sure how much more specific help you are able to offer, or maybe if you prefer, you could recommend someone to take it further.

I have the ability to construct it, just lack the timber data info and experience.

Appreciate any help

Thanks

RayVege patch covering outline

[EricL]

Hello @raymondo

Thank you for posting your proposed plan. I recommend using three of the 100 x 100mm 3.0m Rough Sawn H4 Treated Pine on the 3.2m side. Using the square timber will make it easier for you to mount the Treated Pine Outdoor Timber Framing 70 x 45mm to the top, middle, and bottom of the post. I suggest using Treated Pine Outdoor Timber Framing 90 x 45mm for the rest of the frame. 

To be on the safe side I suggest engaging the services of a builder to have a look at your plan and make sure that the frame can withstand strong winds.

If you need further assistance, please us know.

Eric