by Chris Oct 19, 2021

Allowing For Material Expansion in Balustrades: Everything You Need To Know About Tolerances

Whether you are considering a balustrade or balcony for your home, garden, or commercial space, getting your dimensions and measurements right is crucial. One aspect that is often overlooked is tolerances. But it is more important than ever to consider slight adjustments when measuring and planning a balustrade system.

Thermal expansion is a serious concern with both glass and metal balustrades, and today we are sharing everything you need to know about designing and planning with tolerances in mind.

What Is Thermal Expansion?

The thermal expansion coefficient is a critical consideration when installing any metal or glass structure. It refers to how much a material shrinks or expands when the temperatures fluctuate. Depending on the materials used, they could shrink or expand as temperatures increase. These fluctuations need to be taken into account when positioning the base of balustrades during installation. This is where tolerances are required.

Generally thermal expansion is broken down into two types, either positive or negative. A positive expansion coefficient means that the material expands in rising temperatures. This expansion is caused because the molecules within the material vibrate more at higher temperatures, causing them to take up more room. A negative coefficient means the material will shrink when temperatures rise, but this is a very rare occurrence. With balustrades and balconies, a positive thermal expansion coefficient is usually the only concern.

What Materials Are Affected By Thermal Expansion?

Whether or not you need to consider tolerances and expansion will depend on the material of your balustrades. Common materials including stainless steel and aluminium have a positive expansion and so increase in size in the heat and shrink again when temperatures drop. Balustrades are often exposed to changing temperatures, particularly when they are used outside, so this thermal expansion must be taken into account during installation at any property, as safety considerations should be your number one priority whether domestic or commercially. When you think about the different temperatures we see during the day and overnight, and even comparing summer and winter months, it is clear to see why these changes will take place. The level of tolerances and allowance for expansion will vary depending on the material used:

Aluminium Balustrades

Balustrades made from aluminium are very common and some of our best sellers because of their cost efficiency and sturdiness. With most aluminium fixings, you will need to leave gaps of around 3mm to 4mm to allow for expansion in the heat. Just be sure to consider the temperature during installation, for example, if you are installing in winter you can expect them balustrades to expand by this amount in the summer so space needs to be left.

Stainless Steel Balustrades

Stainless steel balustrades are a little easier to work with because they do not expand quite as much as their aluminium counterparts. Depending on the size of your balustrade, you might not need to leave any gaps at all. We recommend leaving gaps for structures which are over 10m long, and in these cases, the gaps only need to be around 1mm to 2mm every 10m.

Why Use Tolerances When Installing Balustrades?

Our expert team will always supply (and install where necessary) balustrades with thermal expansion in mind and using the appropriate tolerances. It is easy to wonder whether leaving such small gaps is really worth the hassle and time, but there are many reasons to prioritise tolerances when installing balustrades.

  • The Perfect Fit: When you consider material expansion in your fittings, you guarantee that you will have the perfect fit no matter what. Just a few millimetres of expansion in materials can throw everything out and leave your balustrade not fitting as desired.
  • Long Lasting: Failing to use tolerances in your installation can put unnecessary pressure on the materials. While this might not be immediately noticeable, over time it will begin to cause damage to your balustrade. When your fixtures are properly installed and tolerances are used, they will last a lifetime.
  • Cost Efficient: While measuring out the tolerances might make installation marginally longer; the cost savings are well worth it. When you don’t consider material expansion, you could find yourself having to replace part of your balustrade because of damage or insufficient space, which can be costly.

At Stainless Handrail Products, we are specialists in balustrades of all types and sizes. If you are unsure on the appropriate tolerances to use for your fittings, or want your balustrade installed by an expert, contact our team today by calling 01925 387003.


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