Choosing The Best Glass Type For Your Rooflight Project

Date: 16 January 2018
  • Lonsdale Metal Company Ltd |
Choosing The Best Glass Type For Your Rooflight Project
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Date: 15 January 2018

With the myriad of glass type available now, it is often confusing what to choose in terms of safety, thermal and solar performance and balancing cost with the benefits on offer.

Here we consider the most important considerations when choosing the best glass type for your rooflight project:

Choosing The Best Glass Type For Your Rooflight Project


Above all, safety is the critical factor in overhead glazing and the table below summarises what type of glass complies with current Building Regulations at time of writing:

Glazing Height above floor level

Suitable types for Single Glazing

Suitable types for Double Glazing


Up to 5 Metres


Laminated or Wired Glass

The innerpane must be Toughened or Laminated. The upper pane should beToughened in either instance.


5 to 13 Metres

Toughened glass not more than 6mm thick and panes not larger than 3sq/m.

Laminated or Wired Glass

The innerpane must be Toughened or Laminated. The upper pane should

Toughened in either instance.


Above 13 Metres

Laminated or Wired Glass

The lower pane must be laminated


Wired Glass is often used in double glazed combinations. However, there is a high risk of breakage due to thermal stress and advice should be sort from the sealed unit manufacturer.

We do not recommend the use of Toughened Glass in single glazing or to the inner pane of double glazed units over swimming pools, food & beverage preparation units or any areas where the small broken pieces characteristic to this glass type, could cause subsequent injury due to contamination. In these situations laminated annealed glass or polycarbonate would be the best choices.

Choosing The Best Glass Type For Your Rooflight Project



More or less without exception, the outer pane of a double glazed unit should be toughened glass. The inner pane may be toughened or laminated depending upon location and height above ground.

Generally two sheets of toughened glass provide the most economic solution for domestic projects where the roof light is no more than 5m above floor level. If the height exceeds this, then laminated glass should be used for the inner pane.

When it comes to performance, the following are features to consider:

Choosing The Best Glass Type For Your Rooflight Project


This offers improved thermal efficiency retaining more heat within the building.There are to type available standard ‘hard’ coat finish or the more popular ‘soft’ coat which offers a typical centre pane value of 1.2W/m2 when combined with an argon filled cavity.


Choosing The Best Glass Type For Your Rooflight Project


This body tinted toughened glass can be used as the outer pane combined with a laminated low-e softcoat glass to give the added benefit of reducing solar heat gain in the summer months at reasonable cost.


Choosing The Best Glass Type For Your Rooflight Project


The most economic glass tends to be 4-6mm thick which rarely can be installed wider than 1000mm, hence most domestic roof lantern and conservatory installation featuring glazing bars every 600 to 900mm.

However, with the current trend for flat rooflights, single pane rooflights can be installed up to 3m x 6m in one pane of glass.

This calls for specialist manufacturing and installation by experienced companies with the necessary handling equipment and expertise. Much thicker toughened & laminated glass so as not to deflect and care must be taken to ensure compliance with building regulations and local, design wind & snow loads.


Choosing The Best Glass Type For Your Rooflight Project


All of the above glass type can be combined in a triple glazed units achieving both improved sound insulation and U-value as low as 0.60W/m2.K Consideration however, must be given to the additional weight.


Choosing The Best Glass Type For Your Rooflight Project


This has a special coating that provided improved solar control and appear more neutral in colour albeit with a slight grey/green tint. This is often described as 70/30 meaning it offers a 70% light transmission, but only 30% of the sun’s heat enters the building.

600450 Choosing The Best Glass Type For Your Rooflight Project

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Steve Dalton
Wed, 24/01/2018 - 10:27

This calls for specialist production and set up by means of skilled businesses with the important coping with device and information. Much thicker toughened & laminated glass in order not to deflect and care must be taken to ensure compliance with building guidelines and nearby, layout wind & snow masses. 

Bruce C May
Tue, 13/03/2018 - 06:21

Thanks for sharing this amazing read.

tomas wilson
Tue, 02/10/2018 - 15:29

I never doubted it for a second... great piece. 

Chris Charles
Fri, 26/10/2018 - 17:54

Wow! These glass roof ideas are amazing. We are actually looking for something like this for Jacksonville NC towing towing branch extension. This roof is perfectly suited for my business. I hope you can email me with more information.

Marlon E Saratoga
Wed, 21/08/2019 - 03:05

I agree choosing the best roofing company is the best way and it will reflect your business in future.

Marlon E Saratoga
Fri, 23/08/2019 - 02:49

I agree choosing the best roofing contractor is a plus as most of us need quality service and guaranteed. 

Tammy Walker
Fri, 06/09/2019 - 16:20

These are some really great skylight fixtures, it's always nice to see places installing them to add more natural lighting. 

Richard Johnson
Fri, 14/02/2020 - 17:31

Definitely choosing a good roofing company will help to get the job done right. Going to look into getting more sound insulation with my roofer and show him this article. 

Frey L. Karts
Tue, 24/11/2020 - 04:55

Invest in good roofing system, it will make you save in the long run. Also, choose your roofing contractor wisely, you can also do estimation first with your architect for your roofing project.

Anyway, the glass roofing is modern type of roofing system, and it looks elegant too.

Frey |

Mason Miles
Fri, 04/12/2020 - 19:04

This glass goes good with some of our masonry work.  You can really create some beautiful work mixing the two together.  Check out our work here

tomas wilson
Fri, 11/12/2020 - 14:52

Great process development in rooflight installation 

Joe Anderson
Wed, 14/04/2021 - 13:00

I'm planning to get a rooflight  soon. Thanks for the generous tips! :)