Considering scaffold tubes for a ground mount.... thoughts?

[TedM]

I want to add a new ground mount array of just 5 panels located on a spare bit of yard that has a concrete base.
I'm considering making the frame from scaffolding poles as I have a good source of very cheap/free poles and they could be secured using key clamps screwed down into the concrete.

Is there a better option that I'm missing?

[sgt_woulds]

Unistrut.   Mechano for big boys... 🙂 

 

Scaffold poles are harder to cut, not as easy to fit together, and you will still need a way of mounting the panels.

 

However, if the tubes and labour are free...

 

[Bramco]

We used key clamp. No concrete, just whacked some 1m poles into the ground, leaving enough to fasten on to.  But if you've got a concrete base, just use the base/wall mount flanges.  

 

To fasten the panels on, we created a couple of horizontals to give the angle we wanted and key clamp fasteners with  a flange with 2 holes. The panel fasteners were standard solar fasteners - you might need longer bolts but it was pretty easy to find parts and put it all together.

 

[TedM]

I was thinking about using these to clamp the panels to the poles:
https://www.ebay.co.uk/itm/376886172656?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20240627101223%26meid%3D5cf7769367854ef8b06318011d31e8fa%26pid%3D102236%26rk%3D1%26rkt%3D1%26sd%3D376638412709%26itm%3D376886172656%26pmt%3D1%26noa%3D1%26pg%3D4481478%26algv%3DDefaultOrganicWebV9BertRefreshRankerWithCassiniEmbRecall%26brand%3DUnbranded&_trksid=p4481478.c102236.m5337

[Bramco]

Those look great - ours were the standard aluminum ones, so we needed something with a hole in it on the key clamp poles.

 

When it comes to actually installing the panels, we made a couple of plywood jigs to support the panel in place. So a couple of pieces wider than the pole with a notch in and long enough for the top edge of the panel to rest on it. That way, you can lift the panel on, let it rest on the plywood while you fasten the brackets. 

[TedM]

On 09/03/2026 at 15:20, sgt_woulds said:

Scaffold poles are harder to cut, not as easy to fit together, and you will still need a way of mounting the panels.

Cost: The tubes are indeed free! 
Ease of cutting: I've just purchased a 'vintage'* Record pipe cutter for almost no money which means I don't need to use the demon angle grinder 👍
Connecting poles: There's a pretty huge selection of scaffolding tube connectors for about £1.50 each
Mounting panels: see my link above - although £8/clamp is pretty spicy!

AI suggests I make the frame from the scaffolding tubes and then fit unistrut to the frame to mount the panels - so what Unistrut do I need for 5 panels?

* How can a tool be 'vintage' when you can still buy new ones! 🤨

Edited yesterday at 17:05 by TedM

[sgt_woulds]

I like those scaffold/panel clamps - not seen them before but I've been out of the game a while.  Bloody expensive though!

 

Before MCS was introduced to extort money out of the system suppliers and legacy installers, we used unistrut for everything.

 

My vote would be for galvanised unistrut as it will last longer than mankind.  Having said that, if you don't mind a bit of surface rust after a few years then BZP will be fine.

 

We used to get ours from CEF (2 x 21 x 41 mm).  I'd use aluminium T-clamps and mount them to the strut with with short-sprung unistrut channel nuts.  (the springs are a luxury but it makes locating the bolts easier).

 

Be aware of the clamping zones for your panels - clamping outside the zones can induce stress and create microfractures in the cells. 

In extreme cases it can cause 'rapid, unplanned dissassembly' in strong winds...

[JohnMo]

3 hours ago, sgt_woulds said:

We used to get ours from CEF (2 x 21 x 41 mm)

We used 45 square unistrut for ours. Hot dip galvanised. Ring around, as price vary hugely. Ended up paying less that half the cost of my first call to local electrical wholesalers and had 6m long lengths delivered free.

[TedM]

Stupid questions probably but how much gap do I need between panels?
I'm going for 5 panels at 1134mm wide each. 

Can I get away with 2 x 3m unistrut for each horizontal run?

(scaffolding poles being delivered today)

[sgt_woulds]

Assuming 5x1 row then no!   5 x 1134 = 5.67m without considering the clamps (assuming approx 25mm width for each clamp that would add an additional 150mm)

 

Best get 2 lengths at 6m.  

 

You need to make sure that you add enough support to the unistrut rails with the scaffold poles - a proposal sketch would be useful.

 

If you have large overhangs with unsuported unistrut then use 41 x 41mm unistrut instead of 21 x 41 mm.

[TedM]

I'm actually swinging back towards all scaffold pole construction using those ebay clamps (price comes down when you buy 12) as it will handle overhangs better and the poles are free.
I'll see about doing a sketch.

 

Edited 4 hours ago by TedM

[TedM]

Something along these lines.
Front will be around 500mm high and the back will be around 2000mm high (whatever to give 45-50 deg angle).  There will be two diagonals on the rear uprights for bracing.

[saveasteading]

2 hours ago, TedM said:

using those ebay clamps

I've just come across suppliers of tube and plate and fixings at very good prices. metals4U sort of names. Google it.

Better than going through ebay I'd think. 

 

eg I wanted a pair of steel plates cut  to length  4.6m long. They arrived in 2 days for about £15 delivery  ( obv not by Evri).

So your poles could all be precut to length by them and you know the fixings will be compatible.

[-rick-]

https://www.themetalstore.co.uk/products/tube-clamp-uk-suppliers

 

used to be better than metals4u for this sort of stuff. Might have changed recently have not checked.

 

* Not a recommendation never used either, just spent way too long browsing these sorts of companies working out how much it would cost to build ideas.