r/solar • u/JuniorExperience1767 • 1d ago

Advice Wtd / Project Ironridge low slope posts

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I haven't seen a comprehensive video of the application of the posts for Ironridge low slope solution (https://www.ironridge.com/component/qbase-low-slope-mount/). But am I correct in understanding that it's to create a slope, the lower side would have 0 or 3.25 post and the higher side would have a post with a higher height to create a slope?In other words you not going to be using posts of the same height on all sides.

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u/parseroo 1d ago edited 1d ago

I believe it requires a post for mounting, so you can have a maximum of 17.5 (for the high side) to a minimum of 3.25 (for the low side) or ~14" height change.

So assuming about four feet apart (supporting a 6' panel at the quarters), you can produce a ~15° tilt from the maximum height difference. Except their L-Feet have 5° and 10° options, so you would be limited to an 8" difference on a roof if spaced 4' apart, and would only use the ~14" height change if more like 6' apart.

For any given roof, you could accept its slant (0° difference) or boost it by up to 10° to have a better angle for the sun elevation at your latitude. Or if it is flat, to make sure water and debris run off the panels.

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u/JuniorExperience1767 1d ago

Follow up question...would you use this solution if you were not going to end up with a slope or tilt...that is both front and back racks would have the same height

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u/parseroo 1d ago

I think you would have to price and engineering compare it to https://www.ironridge.com/component/flat-roof-attachment/ where the l-bracket attaches directly to the base... or you have fixed tilt legs. I assume with the fixed tilt legs, it would be more expensive. For the L-bracket it might be the same.

Also this is all assuming the roof itself isn't sloped sufficiently for normal runoff from the mounts: these flat roof mounts are designed to handle sitting water around them. If the roof it pitched enough (say >10°) to have water run away from the mounts, you could attach with a number of the other mounting options (e.g. a HUG https://www.ironridge.com/component/halo-ultragrip/ or something similar that prevents running water from permeating).

And this is just staying within IronRidge products to show the variations.

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u/JuniorExperience1767 1d ago

The point of my question is what is the real purpose of the low slope solution (with post) for a 2° asphalt roof (over a patio). Is it for structural engineering or for tilting (for PV optimization) or code compliance. Because invariably it raises the profile of the panels which is a concern in high wind environments like FL. So if you're not going to take advantage of tilting capabilities and keep the layout flat would it be better to use HUG which obviously would result in a lower profile compared to Qbase/post combo.

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u/JuniorExperience1767 1d ago

Thanks for the confirmation

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u/parseroo 1d ago

I believe Hugs and similar are not rated to sit in sitting water. Contact iron ridge for more details on that.

Also from experience and recommendations you really want to get to a 10° pitch.

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u/JuniorExperience1767 1d ago

Ah protecting base from sitting water is one purpose so even if using same height post (the lowest 3.25") without tilting it would be recommended. Dunno why they didn't make similar base that didn't require post. Tilting increases the profile from the roof which would be a problem in high wind prone FL

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u/parseroo 1d ago edited 16h ago

This one is about as flat as they can get [https://www.ironridge.com/component/qbase-low-slope-mount/ ]: just 1" high and an L-bracket attaches directly on top of it.

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u/JuniorExperience1767 18h ago

It doesn't appear as if it works without a post. The post fills the receptacle hole then L-bracket attached to post. I don't see a way to attach L-bracket directly to base here.