Wide or skinny?

I love architects! I love their creative flair, their off the wall thinking, the way they can transform an environment through their work.

But sometimes they make my life a real pain! For example when I’m trying to squeeze their super design into the client’s non-existent budget and keep both parties happy.

One area that often comes up for discussion when we’re working on the cladding design is panel sizes. 

Why is this important, and why does it matter?

Well, let me explain.

Let’s start by talking about large format panels.  Many of you out there want the largest cladding panels you can get, minimum joints, minimalist appearance, panel joints matching with floor levels etc.

This is all ok, panels can be produced up to 6000x2000mm in length. However, as panels get larger, there are some other factors that we have to take into account:

·       The weight becomes heavier the larger the panel becomes (duh). This has to be factored into the price. During the production phase, if the raw sheet of material is over 20kg then it will require more than one man to lift it, which obviously adds cost to the production. Some large panels can weigh up to 75kg. The same issue applies more so when the panel arrives on site and has to be manhandled into position.

·       The structural integrity of the panel itself has to be considered. This applies to the panel width. As panels get wider, there is a greater distance between fixing points (duh) and therefore a greater chance of the panel ‘bowing’ under its own weight; known as oil-canning. This can be overcome by bonding stiffeners to the rear, or in some cases applying aluminium honeycomb to the whole rear surface which completely eliminates any risk of oil-canning. 

·       The structural and wind performance (different to structural integrity) is also a factor. As stated previously, the wider the panel, the greater the distance between the fixings points. This means that the panel is more likely to be sucked off the building in high winds. This can often be calculated by either extra fixings at the joints or mid-point restraints stud-welded to the rear of the panel.

·       Expansion of the material itself if there is not enough room designed in to accommodate it. Aluminium expands 1mm per metre. So with a 6000mm panel, there needs to be a minimum of a 6mm allowed for expansion in the joints. This is often something overlooked, the weight of the panel needs to be held (known as the dead load), but also allow the panel to expand. 

So, yep, you can have them as big as you like, but just make sure there’s enough cost allowed for the extra handling and calculations etc.

So how about small panels, or ‘plank’ type arrangements, are these just a piece of cake?

Well, you certainly don’t need to worry so much about the weight and oil-canning as much, but something that is often overlooked is the fact that having smaller panels is actually sometimes more expensive!

Why would this be?

It stems from the fabrication and installation times. In essence there is more fabrication time and more installation time per square metre.

If you think about it, every time there is a joint it involves an operation to cut and fold the material. In a large panel there is less processing per square metre.

So, are large cladding panels more expensive than smaller panels, or are smaller panels more expensive than larger panels?

To help you decide, I’ve put together some indicative prices to below. Please note these rates are for indicative comparison purposes only, please contact the Bailey sales team for project specific prices.

Now that’s weird….it fluctuates up and down a bit between panel widths doesn’t it? Yes it does, and the reason behind this is down to something called ‘sheet utilisation’ or wastage.  There are standard sheet sizes readily available on the market, and some of the above panel sizes fall just above those sizes meaning that there is a lot of sheet wastage that you are in effect paying for.

To make that a bit clearer, let’s look at the 700mm wide panel above. A 700mm panel, plus the folds required for the joints etc adds up to 865mm of total girth. The nearest standard sheet available is 1000mm. Therefore you are paying for 135mm of wasted sheet per panel. 

So if you were a very economically minded person, you may be asking, what are the optimum panel sizes that occur zero wastage? These would be the following:

·       1335mm

·       1085mm

·       835mm

·       585mm

·       460mm

·       335mm

However…..if your project has enough quantity of the same panel width then your sheets can be de-coiled to the exact widths that you require, so hence occurring zero wastage!

Hopefully some of the above has helped to make clear some of the myths and uncertainties surrounding the widths of panels. As always, if you have queries regarding a particular project, please don’t hesitate to contact one of the Bailey team.