Sun shade sail can u attach it to roof rafter?

I have 18ft 14ft 14ft triangular shade. 

1 side is attached to the wood roof rafter (pic here) via a turnbuckle. The 2nd side is attached to stucco and 3rd side  to concrete brick compound wall.

Wondering if this is safe for the roof or will it cause structural damage on windy days ?

Here we could get wind upto 60mph sometimes.

Now once i had 30mph the sail started shaking vigorously and the turbuckle came out of the hook. This maybe good (from a safety standpoint). But will it always happen at high wind speeds?

Update:

UPDATE: my main question is the foll: Given that the turnbuckle connection is OPEN - will the sail always come off from the turnbuckle when wind speed goes high like 40mph. For example, one day when the wind speed was 25mph it came off. I want it to come off. Its an automatic safety feature even if i am not here on those windy days.

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7 Answers

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  • Mr. P
    Lv 7
    2 months ago

    Instead of the turnbuckle, use a shoelace instead. It will snap before you do significant damage and be a weak link to safely break away.

  • Anonymous
    2 months ago

    You run the small risk that the strapping which stops the rafters lifting may be inadequate, but I should imagine the fixing would fail before that happens. Relying on the turnbuckle itself to decouple at the right moment seems very optimistic.

  • 2 months ago

    basic construction 101:  all masonry products are strong in compression and weak in tension. wood is intermediate. Steel is strong in both tension and compression.

    your sail here isn't safe -- and ordinary wood rafter is, in essence, a 2x4. That's not sturdy enough for the purpose -- you'd want a 4x4 at least.

    Worse, the other ends are apparently anchored in masonry -- that's definitely going to tear loose in high wind and damage the masonry when it does.

    the right way to put up one of these things is via steel poles, well sunk into the ground with serious concrete anchoring each. That steel pole will act as a lever in windy conditions, trying to pry the base out of the ground using the ground level as a fulcrum.  the steel pole also has to be strong enough to not bend.

    Frankly, this is not a DIY job.  and it isn't cheap to do properly.

    Since that defeats the purpose for all but the well to do, what you have to do is take the sail down when wind speed is projected to exceed about 25 mph. that requires some sort of fastener that can open ... a link for that purpose is readily available in the chain area of your local hardware.

    Source(s): grampa -- my son in LA area has one that was done properly. works great to shade the sliding glass doors.
  • 2 months ago

    Attaching it to the rafter is fine. It's coming off because the sail moves in the wind. I suggest using something other than a turnbuckle. A 'quick link' would work well. Make sure you get one large enough to go over the eyes on the sail and the rafter. A double snap shackle would work too. Go and check out the hardware in your local stores. Most places that sell hardware have both those things. If it's going to blow 60mph, take the sail down. The house and the hardware would be fine, but the sail might tear.

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  • elhigh
    Lv 7
    2 months ago

    You run the risk of the sail tearing out, and I think the most tenuous connection is at the stucco.

    Stucco isn't especially strong in any case, and not strong in tension at all.  Your sail is going to put a lot of tension on the connection however, and wind gusts will cause the fastener to move about, microscopically at first but every successive jolt will create just a bit more wiggle room until it finally tears all the way out.

    So to cut to the chase, yes this will cause damage.

  • 2 months ago

    Turnbuckle connects to hook but it is an open connection.

    Will the sail come off the turnbuckle  ALWAYS when the wind speed is high ???? It did come off last time the wind speed was around 30mph.

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  • y
    Lv 7
    2 months ago

    Can't exactly tell what you actually have that anchored in. Damage would actually come down to how that structure was actually made. If you are worried about, I'd use some plastic zip ties, they will break before anything else.  It is recommended that any of those sort of shade things be removed when winds are in the forecast. 

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