Guest Post: Breaking The Law With Heritage Glazing?

Guest Post: Breaking The Law With Heritage Glazing?

There are a number of issues on the plate of the window industry right now. But one that perhaps need more attention lies in the heritage glazing part of our market.

Colin Torley, formerly of VEKA but now heads up the multi-material company the Saveheat Group, has decided to tackle the issue of non-compliance head on in this well written guest post.

Having been in the window Industry for over 30 years, predominantly on the supply of PVCu profiles. I always found that we would do everything to comply with all the rules and regulations regarding the manufacture and supply of window products to the market.

Having recently been involved in the formation of the Saveheat group, which is made up of 4 companies manufacturing 4 window products including PVCu, Timber, Aluminium and IGU’s. It’s the timber side that concerns me most. My concerns are not about what is the best material for windows, but rather the glass units that some companies are putting into these timber windows and the claims that are being made.

There are widespread concerns in the Industry in relation to the durability of narrow cavity, reduced sightline insulating glass units. (IGU’s)

All IGUs placed on the European Market (including the UK) must, under the Construction Products Regulations, be manufactured in accordance with all parts (1 to 6) of EN 1279, the harmonised European Standard for Insulating Glass Units.

The primary requirements of EN 1279 to demonstrate durability of the IGU, to provide a reasonable service life are:

Testing to EN 1279 part 2 – Long term test method and requirements for moisture penetration

Testing to EN 1279 part 3 – Long term test method and requirement for gas leakage rate and for gas concentration tolerances

There also needs to be a clear system description to prove that the test evidence, that some companies are producing, relate specifically to the low sightline narrow cavity units and not to standard units.

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The majority of manufacturers producing these IGUs are using a ‘warm edge’ spacer bar with a height of 3mm and although the manufacturers of this spacer bar are unable to pass the required test with a sealant depth over the spacer bar of 5mm or more, making an overall sightline height of  between 8 to 10mm, many manufacturers of these IGUs reduce this sealant depth to 2mm to achieve a 5mm sightline. This is specified (wrongly) by a number of local authorities and other bodies to give a reduced visibility of the spacer bar,  therefore giving more of a single glazed appearance, and to enable narrow ‘’through’’ glazing bars /astragals in multi-pane items. The problem with this is that the reduction of this sealant depth seriously affects the IGU’s ability to resist moisture penetration and gas loss which in turn results in premature IGU failure.

Modern Timber window manufacturing techniques allow multi-pane windows and doors to be manufactured with single pane IGUs with normal height perimeter sightline / edge seal, sub-divided within the IGU cavity and once glazed, fitted with a structural glazing frame to the inner and outer faces of the IGU, accurately replicating narrow “through” glazing bars, but offering the durability and thermal performance expected by home and building owners of modern, double glazed windows and doors, which would also allow them to comply with EN1279.

I have spoken to a number of people in the industry and no one seems to be aware of any IGU’s currently on the market with sightlines below 8.5mm that comply with the required standard (EN 1279) and therefore cannot demonstrate the durability expected of an insulating glass unit.

As a manufacturer of IGU’s, who have the ability to manufacture these units, we have decided to take a stance and only supply a product that complies fully to the Industry standards, but we seem to be a lone voice out there.

I would hope that the Industry regulators, Planning and Conservation officers, Architects and other specifiers pick up on what we are trying to do and support us, as there is product being installed that is illegal, there is an issue over heat loss, noise reduction, safety and security and to top it all it can cost 40-50% more than compliant product.

I believe that the best way to stop this is for the industry to stop turning a blind eye to this and look at how we get together to stop it happening altogether before it does even more damage to the industry.


Colin Torley

Sales and Operations Director

Saveheat Group

9, Baker Street, Greenock PA15 4TU

Tel           01475 601960

Mobile   07764 453842

E-Mail     [email protected]

I agree completely with everything Colin talks about in this article. But, if this is an issue that has been known about and has continued to go untouched, you have to wonder if there are any trade bodies out there with any teeth or willpower to tackle this issue, among the many others our industry faces right now.

I want to thank Colin for reaching out and allowing me to publish this article. If you have any thoughts or comments on this post, please leave them via the comments section below.

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By |2017-10-03T21:47:18+00:00October 3rd, 2017|Categories: double glazing industry|

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Andrew MadgeColin TorleyHugh EadieColin TorleyGarry Monk Recent comment authors

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Scary how bold companies can get with their claims when they are non compliant products, and even more worrying when as you say, its used as a cost booster. Not the way to do business….

Garry Monk

I agree we have a number of issues within our industry and EN1279 is one, however when so called Heritage units are being used on listed property this falls outside normal rules and each project is viewed on its own merit (rightly or wrongly). I am aware units get used in projects where Windows should be registered with Building Control but this is a wider problem, so many jobs installed not registered or compliant and even when windows registered within CPS units are not checked for EN1279 compliance by inspectors. Back to Heritage units, I am aware of one company… Read more »

Colin Torley
Colin Torley

I would be interested in seeing a copy of that test report. Talking to BSI and the test houses, no one has had EN1279 parts 2 and 3 passed. If someone has, then lets have a look at it and hold them up as the shining light of this problem.

Colin Torley
Colin Torley

Hi Gary, Have you managed to find the copy of the test report that you mentioned. As per my previous E-mail< I would treally be interested in seeing this. Colin

Garry Monk

Hello Colin, sorry for the delay I had to check with companies concerned how much detail I could give. The Company that made units is Safeguard Glazing Supplies Ltd via The Northern Test House and BSI report number 2370/8313547. I would suggest speaking to Brenda at Northern Test House and she will be able to do look after your EN1279 testing requirements.

Hugh Eadie

Colin, this is an ‘old chestnut’, of your fellow Director. The facts are that this so called professional industry of ours, continues to break the rules and ignore policy as laid down by Building Standards and in your part of the industry (timber sash and case windows) Historic Scotland. As far as I’m aware there is no timber window available currently which complies with the sight lines required by Historical Scotland, regardless of the construction of the sealed unit which as you say “accurately replicating narrow “through” glazing bars”. So, in my view, by you proffering “multi-pane windows and doors… Read more »

Colin Torley
Colin Torley

OK Hugh, you have ,made your point so what are you going to do about it, nothing by the sounds of it and will just continue to accept that our industry just isn’t policed. You are well enough known to be able to ask these questions to the relevant people, so put your head above the parapet for once. The fact that the law is continually being flouted by Historic Scotland, Edinburgh Council etc amongst others. There is no better time to hit out at companies who aren’t complying with the relevant specifications. My aim is, as a minimum, to… Read more »

Andrew Madge

As a high quality manufacturer of timber windows, with a background of work in the conservation sector, we have been battling with the slim glazing problem for years. The manufacturers will be stuck in a Catch-22 situation, where they either provide products with this glazing or lose the order. Our approach has been to develop an entirely new product range around vacuum cavity glazing, with large panes and plant on bars. These products have a real single glazed window aesthetic (0.2mm cavity, 6.5mm overall unit thickness), while also providing the performance and longevity we should expect of our industry. Hopefully,… Read more »

Colin Torley
Colin Torley

Hi Andrew, That’s great that you have won an award for an alternative to the heritage glazing, but there are still a large number of contracts going ahead that do not comply with the current regulations and we need to try and put a stop to it, by challenging each and every one that comes up.

Andrew Madge

Absolutely agree Colin, but no doubt we all understand the challenges of breaking a specification written by an architect/conservation officer when you are tendering to the main contractor.

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