Best Self Supporting Glazing Bars

With the rise in timber costs, self supporting glazing bars are becoming an increasingly more economical option when building a canopy roof or lean-to conservatory roof.

Quite simply, self supporting glazing bars are glazing bars that can be installed without a structure directly supporting them below. Standard glazing bars (both PVC and Aluminium) require rafter support below with either a timber or steel frame. Building your glass roof or polycarbonate roof with self support glazing bars can have significant benefits. However, installers sometimes shy away from using them as they are unsure which option is best.

There are two main types of self supporting glazing bars: fully aluminium bars or mixed PVC and aluminium bars. For this comparison, we will call the bars made from a mix of both PVC and aluminium just PVC self supporting to avoid confusion, however, it is worth noting they include a mix of materials – more on this later!

In this guide, we will compare the market-leading options of self supporting glazing bars across a range of metrics to find out which is best for you! To skip down the contents, click below:

Colour Options

Both PVC and aluminium self-supporting bars offer a wide range of colour options to suit different styles of projects. For both types white is the most popular colour and so has the lowest cost with other options having a premium for the less common colours. The aluminium bars offer standard colours of brown and white for the same cost, unlike PVC, so there is a brown option without the cost premium. In comparison, PVC offers just white at the base cost.

For options other than standard colours, PVC bars have limitations due to being manufactured from plastic meaning there are only four other colour options, for example, rosewood and black. Without getting too technical, PVC self supporting bars have this colour limitation issue due to an issue with colour fastness. In layman’s terms, this means the ability to hold the colour over time and not fade. Imagine how faded PVC gutters look for example. We will explain more about this in the next comparison of  lifespan.

On the other hand, aluminium self supporting bars can be manufactured in any colour! This is a big benefit which means you can pick any RAL colour to match your house’s colour theme or style. Popular colour examples include Agate Grey (RAL 7038), Fir Green (RAL 6009) and Cobalt Blue (RAL 5013).

Winner: Aluminium Self Supporting Glazing Bars

Quality and Lifespan

It goes without saying, aluminium is a lot more durable than PVC, a plastic, even in its raw state. This is why installers prefer aluminium bars for their superior expected lifespan of 20 years.

PVC can be badly affected by weathering over time, going brittle or the colour fading. This is especially the case for dark colours like grey, black and brown where the sun’s rays can cause major discolouring. If considering PVC self supporting bars then white is the only way to go.

Another challenge PVC bars face is warping in the sun’s heat. PVC (Polyvinyl Chloride) is a thermoplastic meaning that when it is under a lot of direct sunlight it can heat up and warp or melt.

Dark colour PVC heavy duty bars are increasingly facing this challenge with rising summer temperatures over the last few years. Below is an example picture of a faded and warped PVC self supporting glazing bar. An aluminium glazing bar will not do this!

Faded warped pvc self supporting glazing bars image

Even with the core of the bar being aluminium if the outside plastic capping is affected it can cause you to have to replace the whole roof early. Using aluminium bars gives you an extra 10 years which in turn reduces the lifetime cost of the reduce by having to replace as often.

Overall, an aluminium self support bar does have a strong edge on quality, with a lifespan that is hard for PVC to compete with. Everything on the bar is aluminium, including the bar end caps which offers unrivalled quality.

Winner: Aluminium Self Supporting Glazing Bars


Despite being manufactured from different materials both aluminium and PVC self-supporting glazing bars have a very similar cost. This means installers should give careful consideration to which one is more quality and will last longer and the overall project cost will be the same.

Use our canopy calculator or contact our team for help with quoting your dream self supporting installation.

When pricing up your canopy roof you are always best to get a full quote built as beyond the main standard bars both types have varying parts required. Not all PVC glazing bars coms with end caps or fixings for example. All aluminium self-supporting bars come with bar fixings if you order the polycarbonate from the same place. Saving you the hassle of sourcing yourself!

Winner: Tie


PVC isn’t strong enough in itself to be self supporting which is why PVC heavy duty self supporting bars are made from a mixture of PVC and aluminium inside. Spanning is dependent on a wide range of factors, such as rafter centres and glazing type etc so it is hard to create a fair comparison.

At a bar spacing of 700mm, both types of self support glazing bars can achieve circa 3.4m spans. You can go narrower to achieve longer spans but it is a question of the benefits versus the  look of very narrow roofing sheets or glazing

However, aluminium self supporting bars have a big advantage – they are available in Low Profile or High Span! High span self supporting glazing bars are designed to achieve incredible free-spanning lengths up to 6 metres. With reasonable

Please be aware: Spanning capabilities are dependent on a wide range of factors such as location, exposure, regional loading requirements, glazing type and more so we cannot guarantee any results will be achieved. If you are unsure, please consult with a structural engineer.

Winner: Aluminium Self Supporting Glazing Bars

Design and Style

PVC and aluminium follow contrasting design styles but broadly speaking fit into a wide range of project looks. With aluminium bars having a shallower top cap they offer a more modern seamless style, particularly on the exterior. On the other hand, PVC glazing bars are more contemporary, have a larger overall profile height and look a bit more budget

With aluminium cast bar end caps and beam end caps, the aluminium self support roofing arguably has a neater finish on the outside as well as has hidden fixings. Whereas the PVC end caps and exposed fixings can look a bit more utilitarian.

This is definitely a tie as all said and done it depends on what look you are trying to achieve. Some installers say aluminium systems offer a better timeless style that is classy and clean, but it is essentially personal preference.

Winner: Tie

Glazing Options

PVC bars hold the glazing with a snap fix which means they are limited to set thicknesses, including 16mm, 25mm and 35mm. This sadly rules out the most cost effective polycarbonate option which is 10mm twinwall polycarbonate sheeting, which is used a lot in DIY canopies for residential. It also rules out the use of solid polycarbonate sheet glazing which is very popular for station canopies, school canopies and shelters.

Due to the snap fix style, PVC self supporting bars are not suitable for use with glass. Theoretically, they could clamp to the thickness of 24mm glass units but as glass is a lot heavier than both polycarbonate types (double solid and 10 times multiwall) it will not hold the glass glazing securely. Over only a short period the glass will slip and cause major issues.

In comparison, self supporting aluminium glazing bars are manufactured to work with any thickness of glass or polycarbonate glazing. Whether you are needing self supporting glazing bars for 6mm glass or 25mm polycarbonate sheets the same aluminium bars can be used for a high-quality finish. This offers a vast range of glazing option choices for installers, depending on where the roof is being installed.

For external roofs, like a canopy roof or lean-to gazebo, the thinner solid roofing sheets are popular like Axgard 6mm sheets or glass. For roofs covering an internal room then multiwall polycarbonate or double glazing is best.

This wide variety of glazing is not something you can get with PVC self supporting bars, unfortunately. As a great self supporting glazing bar for glass roofs or polycarbonate, the aluminium bars are a clear winner on this point.

Winner: Aluminium Self Supporting Glazing Bars

Delivery Speed

Aluminium glazing bars again have an advantage here as, bar bespoke colours, are available in 1-2 working days compared to the 5-7 days of PVC self supporting bars. Order today and you could get your roof project started without delay.

Installers often consider polycarbonate roof carport systems as a straightforward way to get a set-size roof kit with all the items required. However, this has major delivery disadvantages with the minimum lead time being at least 4 weeks plus. If you need help building a quote live chat with our team or enter your exact dimensions into our roof canopy kit calculator and delivery will be just 1-2 days!

Winner: Aluminium Self Supporting Glazing Bars

Overall Winner: Aluminium Self Supporting Glazing Bars

When looking for a self supporting glazing bar, you should definitely consider an aluminium glazing bar rather than a PVC glazing bar. Considering all the pros and cons, aluminium glazing bars have the upper hand on lifespan, colour options, spanning, quality, glazing options and delivery speed. All these benefits without any additional cost – a no brainer choice!


Aluminium Self supporting 

PVC Self supporting 

Colour Options

White & Brown (+ any bespoke colour)

White (+ 5 special colours)

Quality & Lifespan

20+ Years

10 Years (Warp & fade risk)


Similar Costings


3.4m* (Low Profile) and 5.5m* (High Span)


Design & Style

Personal Preference

Glazing Options

Any Glazing (polycarbonate & Glass)

Polycarbonate (16, 25, 35mm)

Delivery Speed

1 –2 Days

5-7 Days

Overall Winner




*Spanning capabilities are dependent on a wide range of factors such as location, exposure, regional loading requirements, glazing type and more so we cannot guarantee any results will be achieved. If you are unsure, please consult with a structural engineer.


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