How to install a shade sail over storm water drain?

[AntonT]

I have a patio area that I would like to install a rectangular 4 x 5m shade sail in. I can attach 2 corners to the roof using the relevant fasteners, but on the other side I have a wooden fence so it makes sense that I would have to install 2 posts.

The issue I have is that the place the posts need to go are over a storm water drain and I am therefore very limited in the depth I can dig.

Is there any way to install posts without burying 1/3 of the post? Can stirrups be used for example? 

[EricL]

Hi @AntonT 

Thanks for sharing your question about mounting a shade sail in your patio area. Would it be possible for you to post a few photos of the shade sail area and where the storm drain is. It would definitely help our members think of possible mounting alternatives for your shade sail.

In regards to the stirrups, you'll still need to create a base to anchor it in which means that you'll need to dig a foundation in the soil and fill it with concrete.

If you need a hand posting the photos, please let me know.

Eric

[AntonT]

Thank you very much for your response.

The stormwater drain runs along the fence, but I'm not clear if it is on my property or next door. The Water authority advised that anything deeper than 500mm will require a permit, which I am hoping to avoid.

In the photo, I have marked the likely spot for the stormwater drain, and my proposed posts.

It should be noted that there was previously a very old patio there with 2 x 2600mm timber posts (400mm buried) in the same line as my proposed posts (that I had removed), connected to the fascia.

[Dave-1]

Good Afternoon @AntonT 

I always wonder how deep posts ect need to be for shade sails. Should they be installed at an angle or Vertical even. 

With your shade sail wanting to go to the fenceline almost I have two thoughts on getting around the stormwater pipe 500mm down.

First thought is to make up something like an L frame (preferably steel) and then put in a block of concrete. This would help the post stay Vertical and not need such a deep hole. (The L faces the line the shade sail will pull on)

Second thought is from Gardening Australia. Someone wanted a post in a rental but couldnt dig. So they filled a metal garbage bin with rocks and the post being in the center. It looked solid. For you maybe dig a hole 400mm concrete that in, put a garbage bin (or something else) over the post and then fill it with rocks as well. The weight would help keep the post Vertical without needing the depth.

Dave

[AntonT]

Hi Dave.

Those are really good suggestions. I might talk to a friend who could mock up a steel frame for me to be filled with concrete. He might also let me know if that's structurally sound - the shade sail posts do get some stress from the wind.

Shade sail posts ideally should be 1/3 in the ground and on a 5-7 degree angle away from the base point (ie angling away from the sail). But perhaps I can have the steel frame made with those angles on a smaller tube I could slide then slide the full posts over before concreting. 

Certainly excellent suggestions that I'll take on board. Thank you.

[EricL]

Hi @AntonT 

Thanks for posting the photos of your patio area. It's great that you've received excellent advice from @Dave-1. Just to add to the suggestions made, I recommend having a look at installing offset mounting points for the shade sail. In this manner you can dig away from the storm drain and still get maximum use of the shade sail. Plus, you can combine it with @Dave-1's idea to get a really strong mount.

I've placed a sketch below to give you an idea of how it can be assembled. Please have a look and tell me what you think.

If you have any other questions we can help with, please let us know.

Eric

[AntonT]

That's really interesting, and very different to what I was thinking. Which is why I love this forum. I might talk to my friend to see what it would take to do something like this.

I also have some artificial vine, so I'd consider putting some horizontals accross between those beams, so that I can hide our fence and give a better ascpect from inside the unit looking through the bifold doors.

Lots to think about.

[AntonT]

Hi everyone. 

Thank you for all your suggestions. 

After discussions with the utility companies and the council, we have decided not to proceed with the project, as a bunch of permits are required for any digging.

We are going with a cantilever umbrella as a quick and cheap solution.

I appreciate the suggestions from everyone, and thought it was polite to complete this discussion.

[Jason]

No worries @AntonT, thanks for letting us know. 

Feel free to ask if you need any umbrella recommendations.

Jason

[Dave-1]

Morning @AntonT 

Thank you for letting us know, I always find it interesting how projects procede or not. We all have projects that get snapped right hand because of other unkowns. Ideas are easy, implemtation can be hard.

Dave