Was MgO Board Banned? What Happened in Denmark and What Changed

We found no statutory ban on magnesium oxide board in Denmark. In 2015 the housing ministry and the building defects fund Byggeskadefonden found the boards unsuitable as wind barriers in the Danish climate, the market stopped using them, and arbitration later assigned the repair bills. In the UK, warranty insurers stopped accepting MgO boards in 2020, which the RICS describes as effectively prohibiting them.

“Banned” is how the story is usually retold, and the difference matters if you plan to make or sell MgO boards. A ban would be a legal question. What happened was a market and liability event: the people who insure, specify and build stopped accepting a product that had failed. That kind of rejection is harder to reverse than a regulation, because the boards have to win back insurers, specifiers and building officials rather than one regulator.

Below is the public record by country and what it means for a producer. For why chloride boards sweat and corrode fixings, see MgO board problems; this article does not repeat the chemistry.

Was Magnesium Oxide Board Banned? The Short Answer by Country

What Happened in Denmark: The Timeline

Denmark is the case behind almost every “MgO board banned” search. The sequence below is built from the Danish housing ministry, Byggeskadefonden’s reports and the Danish engineering weekly Ingeniøren.

1. 2007–2010: introduction. MgO boards were first used in Danish buildings in 2007, and use accelerated after 2010 (Ingeniøren, September 2015). They were installed as the wind barrier behind ventilated facade cladding.
2. 2010–2014: rapid take-up. The Copenhagen Post reported that as much as 100,000 m² were sold each month from 2010 until the problem came to light at the end of 2014. By the end of 2012, MgO boards made up 75% of the Danish market for wind-barrier boards, according to the contractor MT Højgaard (Ingeniøren, 2018). In December 2013 the trade publication Byg-Erfa listed magnesium-based board among five possible wind-barrier materials; Byg-Erfa says it did not test the product.
3. March 2015: warnings. On 6 March 2015 Byggeskadefonden notified social and municipal builders of moisture problems (ministry memo). Byg-Erfa published a warning sheet against using MgO boards as wind barriers the same month.
4. August 2015: no ban, but no market. The largest contractors had stopped using MgO boards and most retailers had stopped selling them, but one wholesaler kept them in its range, saying they were tested and approved under the applicable rules and blaming installation errors (Ingeniøren, 13 August 2015). That boards were still on open sale fits the absence of any legal ban.
5. September 2015: the fund’s verdict. Byggeskadefonden published studies by Bunch Bygningsfysik and Overfladeteknik, with laboratory tests at DTU and Force. They concluded that “MgO-plader er uegnet til anvendelse som vindspærre under danske klimaforhold”: MgO boards are unsuitable as wind barriers in the Danish climate. The fund now expected almost all boards to need replacing within its 20-year cover period.
6. October 2015: the ministry. A housing ministry memo to the Danish parliament repeated that the boards are unsuitable as wind barriers in the Danish climate and should be replaced in most cases. It mentions no ban. It notes it was still unclear whether responsibility lay with building owners, contractors, consultants, importers or the producers in China.
7. 2017–2019: arbitration. The construction arbitration board began deciding who pays (see below).

Two details change how a producer should read this. First, the failures were in one demanding use: an exterior wind barrier in a cold, humid climate. Second, the boards were widely accepted before anyone tested them for that exposure. The later research, including the 2019 DTU study covered in MgO board problems, came after the market had adopted the product.

How big was the Danish MgO board problem?

The scale figures depend on who counted and when:

• Area. Dansk Byggeri, the contractors’ association, said up to one million square meters of MgO wind-barrier board had been used in Danish homes (Ingeniøren, October 2015).
• Social housing. By 2017 Byggeskadefonden had identified 82 social-housing projects with MgO boards in their facades since 2010, covering about 11,500 homes; 62 of them, about 9,000 homes, were handed over before the March 2015 warning and fell under the fund’s insurance (Ingeniøren, 2017).
• Cost. Estimates range from roughly DKK 800 million to over DKK 1 billion, depending on the source. The housing ministry’s 2015 memo put replacement in social housing at about DKK 800 million, with large uncertainty. The Copenhagen Post reported in August 2015 that the boards could have caused damage of over DKK 1 billion, and Ingeniøren reported a similar figure of about DKK 1 billion from Byggeskadefonden’s advisers, based on an average repair cost per square meter.

The cost was high because the boards sat behind the facade cladding, so the repair cost depended on what had to come off in front of them, from light cladding to brick (Ingeniøren, August 2015).

No Legal Ban Found, and Why It Did Not Matter

Nothing in the public record we reviewed shows a Danish authority ordering the boards off the market. What decided whether they were used was the chain of people who carry the risk: the client, the consultant who specifies, the contractor who builds, and the insurer who covers the defect. In Denmark each link broke at once:

• Insurance. Byggeskadefonden, which insures social housing against building defects, issued the March 2015 warning and later expected most boards to need replacing.
• Specifiers and contractors. After the warning, using MgO boards as a wind barrier meant accepting liability for a known defect. Contractors switched to other boards; one cladding supplier said it would “probably never” use MgO boards again (Ingeniøren, August 2015).
• Industry guidance. Byg-Erfa, whose 2013 sheet had listed the boards, published a warning against them in March 2015.

Dansk Byggeri’s response was not a ban either. In October 2015 it proposed a standing building panel to collect experience with new materials and check them before they spread through the industry, drawing on producers, consultants, tradespeople, SBi, Byg-Erfa and Byggeskadefonden. Its director warned that the panel “must not become a technical trade barrier” (Ingeniøren, 14 October 2015).

Who Paid: The Danish Arbitration Rulings

The liability rulings matter more to an exporter than any ban would have, because they show who in the chain ends up carrying a product failure. We have not seen the awards; the summaries below are as reported by Ingeniøren.

Sources: Ingeniøren, 23 and 26 June 2017, 17 September 2018 and 3 May 2019.

The thread through all three: the boards were new to the use, and nobody had shown they were fit for it. The lawyer for the building owner in the 2019 case expected clients to stop relying on trade publications and to require that materials be fully investigated. That is the attitude your boards now meet in any market that remembers Denmark.

United Kingdom: Warranty Insurers, Not Regulators

In the UK, demand for MgO boards grew after the Grenfell Tower fire. Regulation 7(2) of the Building Regulations 2010 requires materials that become part of an external wall of a relevant building (broadly, a building with a storey at least 18 m above ground that contains dwellings, an institution or residential rooms) to be of European Classification A2-s1, d0 or A1. MgO boards are often non-combustible, Euroclass A1 (RICS, 2021), so they became an option for sheathing behind cladding.

Then, in spring 2020, NHBC, Premier Guarantee and LABC said they would no longer accept MgO boards on any schemes they insure (RICS, 2021). These are warranty providers for new homes, not regulators, yet the RICS describes the decision as “effectively prohibiting the use of the material.” The concerns cited were chloride salts and organic material such as wood chips left in poorly made boards, moisture weeping in high humidity, corrosion of fixings, and approvals based on tests developed for other kinds of board.

The industry’s answer was a specification. In September 2021 BSI published PAS 670, a specification for both chloride and sulfate MgO boards used as partitions and as internal or external linings. It sets requirements for how boards behave in humid conditions and over time, and for factory production control and traceability; it does not cover flooring, sarking or roofing. For a producer selling into the UK, PAS 670 test evidence is now the starting point of any conversation; check with the buyer which warranty provider covers the project and what it currently accepts.

Other Markets: Sweden, Canada, the United States and Australia

Sweden. The Danish findings reached Sweden in October 2015. A researcher engaged by the Swedish homeowners’ association Villaägarnas Riksförbund found that the same brand used in damaged Danish buildings had been sold in Sweden since 2009, with one importer alone selling 10,000 to 15,000 boards. That importer stopped selling them. The association reported the boards to the market control of Boverket, the Swedish building authority, and asked for an investigation like the Danish one (Ingeniøren, 16 October 2015).

The boards had a Swedish product certification and had passed some tests, but their moisture absorption had not been tested before they reached the market. Certification for the wrong properties did not protect anyone.

Canada. The Canadian Construction Materials Centre (CCMC) issued an advisory to building officials in July 2017 and updated it on 1 March 2018. It is guidance, not a ban: it recommends caution in approving any MgO board in wet or humid environments, and says boards it has not evaluated should not be used above 84% relative humidity or in direct contact with steel studs or other metal components. The advisory deals mainly with oxychloride boards and states that CCMC has not evaluated oxysulfate or oxyphosphate products. It also notes that one MgO board’s CCMC evaluation was cancelled in January 2018, while another remained listed with a requirement for stainless steel fasteners.

United States. We found no ban. The International Code Council has published ICC 1125, a standard for classifying MgO boards for wall sheathing, tile backer, floor sheathing and roof sheathing, with testing for moisture movement, corrosion resistance, impact resistance and surface burning, and optional provisions for fire-resistance-rated and noncombustible construction. A classification standard is the opposite of a ban: it gives boards that pass a defined route into codes.

Australia. We found no national ban. The CCMC advisory cites Australian evidence that MgO boards react with metal, especially when moisture is present, including corrosion of metal structures in high-rise buildings. A University of the Sunshine Coast study of MgO cladding products on the Australian market found that the boards were chosen mainly for fire resistance; at 75% RH staining and water absorption were not a problem, but at 97% RH they appeared in all but one product. The authors implicated chloride from the binder and called for standard characterization of MgO boards before use in high-humidity environments (Jays et al., 2019).

What This Means for an MgO Board Producer

We found no statutory ban in any market we looked at, but the markets that had failures now ask for evidence before they accept the product. That shifts the work from marketing to the plant and the test lab:

The binder choice is the first step, not the last. The lines we supply make magnesium oxysulfate boards as standard, because sulfate boards have much lower chloride than oxychloride boards. But sulfate is not a pass in itself: in the DTU humidity study the sulfate boards also took up large amounts of water, only later than the chloride board. Sell each board only into the uses it has been tested for, and treat exterior wind barriers and sheathing in humid climates as uses that need specific proof. For the comparison of the two binders, see magnesium oxysulfate vs oxychloride board; for how other boards compete in the same applications, see MgO board vs gypsum board vs fiber cement board.

FAQ

Is MgO board banned in Denmark?

We found no statutory ban in Denmark. In 2015 the housing ministry and Byggeskadefonden concluded that MgO boards are unsuitable as wind barriers in the Danish climate and should in most cases be replaced. Contractors and most retailers stopped using and selling them, and arbitration rulings, as reported by Ingeniøren, assigned the repair costs. One wholesaler was still selling boards in August 2015.

Is MgO board banned in the UK?

We found no statutory ban. In spring 2020 the warranty providers NHBC, Premier Guarantee and LABC stopped accepting MgO boards on the schemes they insure, which the RICS described as effectively prohibiting the material in new homes they cover. BSI then published PAS 670 in 2021 as a specification for MgO boards. Check what the project’s warranty provider accepts.

Is MgO board banned in the United States or Canada?

We found no statutory ban in either country. In the United States, the International Code Council has published ICC 1125 for classifying MgO boards, including sheathing and tile backer uses. In Canada, CCMC advised building officials to be cautious, to avoid non-evaluated boards above 84% relative humidity and to keep them out of direct contact with steel other than stainless fasteners. That is guidance, not a ban.

Were sulfate MgO boards part of the Danish problem?

The Danish cases mainly involved chloride boards: most boards analyzed for Byggeskadefonden contained about 10% chloride, and Danish damage guidance describes boards containing magnesium chloride. A 2019 DTU study tested both types and found that sulfate boards dripped later than a chloride board but still absorbed large amounts of water, and its authors did not recommend either type as a wind barrier in Denmark’s climate.

Can MgO boards still be sold in Europe?

We found no ban that stops them. In the UK, for example, they are used as sheathing behind cladding because they are typically non-combustible, Class A1 (CWCT). What has changed is the evidence buyers expect: chloride content, humidity and corrosion test results, compliance with a named standard such as PAS 670, factory production control and a clear statement of approved uses. Producers who cannot supply that evidence find it hard to sell to specifiers and insurers.

Planning an MgO Board Plant?

If you are planning MgO board production for export, start from the standard and the tests your buyers will ask for, then choose the formula and the line. See our MgO board production line for the equipment, the MgO board manufacturing process for the production flow, and the MgO board plant setup guide for the full planning sequence.

Sources

• Danish Ministry of Immigration, Integration and Housing, Orientering vedr. MgO-pladesagen i det almene byggeri (memo, 1 October 2015), Folketinget UUI Alm.del Bilag 11: https://ft.dk/samling/20151/almdel/UUI/bilag/11/1554986.pdf
• The Copenhagen Post, “Building sector fears fallout from fungus-forming facade panels” (14 August 2015): https://cphpost.dk/?p=25098
• Ingeniøren, “Regning for fugtramte vindspærreplader kan løbe op i over 1 mia. kr.” (4 August 2015): https://ing.dk/artikel/regning-fugtramte-vindspaerreplader-kan-loebe-op-i-over-1-mia-kr
• Ingeniøren, “Dansk grossist fortsætter salg af MgO-plader trods advarsler” (13 August 2015): https://ing.dk/artikel/dansk-grossist-fortsaetter-salg-af-mgo-plader-trods-advarsler
• Ingeniøren, “Byggeriets ekspertpanel anklaget for at blåstemple saltvandsplader” (18 August 2015): https://ing.dk/artikel/byggeriets-ekspertpanel-anklaget-blaastemple-saltvandsplader
• Ingeniøren, “Rapport: Næsten alle MgO-plader skal skiftes” (23 September 2015): https://ing.dk/artikel/rapport-naesten-alle-mgo-plader-skal-skiftes
• Ingeniøren, “Dansk Byggeri vil forhindre MgO-gentagelse med kontrol af nye byggematerialer” (14 October 2015): https://ing.dk/artikel/dansk-byggeri-vil-forhindre-mgo-gentagelse-med-kontrol-af-nye-byggematerialer
• Ingeniøren, “MgO-skandalen rammer nu også Sverige” (16 October 2015): https://ing.dk/artikel/mgo-skandalen-rammer-nu-ogsaa-sverige
• Ingeniøren, “Arkitekt dømt til at betale millionerstatning for fugtsugende MgO-plader” (23 June 2017): https://ing.dk/artikel/arkitekt-doemt-at-betale-millionerstatning-fugtsugende-mgo-plader-200785
• Ingeniøren, “Byggeskadefonden: Nu skal vi gennemgå alle vores MgO-sager” (26 June 2017): https://ing.dk/artikel/byggeskadefonden-nu-skal-vi-gennemgaa-alle-vores-mgo-sager-200908
• Ingeniøren, “Efter ny MgO-kendelse: MT Højgaard hensætter 400 mio. kr. til erstatninger” (17 September 2018): https://ing.dk/artikel/efter-ny-mgo-kendelse-mt-hoejgaard-hensaetter-400-mio-kr-til-erstatninger
• Ingeniøren, “Voldgiftssag: Entreprenør har ikke ansvaret for skader fra MgO-plader” (3 May 2019): https://ing.dk/artikel/voldgiftssag-entreprenoer-har-ikke-ansvaret-skader-fra-mgo-plader
• Tommy Bunch-Nielsen, Bunch Bygningsfysik, Skivor av magnesiumoxid (presentation, Fuktcentrum, Lund University, 16 March 2016): https://www.fuktcentrum.lth.se/fileadmin/fuktcentrum/PDF-filer/INFOdagar/Infodag_Lund/2016/SkivorMagnesiumoxid-TBN.pdf
• S. W. Nielsen, C. Rode, T. Bunch-Nielsen et al., “Properties of magnesium oxide boards used as sheathing in exterior walls,” MATEC Web of Conferences 282, 02091 (2019): https://www.matec-conferences.org/articles/matecconf/pdf/2019/31/matecconf_cesbp2019_02091.pdf
• CWCT, “The use of magnesium oxide (MgO) boards”: https://www.cwct.co.uk/blogs/latest-technical-new/the-use-of-magnesium-oxide-mgo-boards
• RICS Built Environment Journal, “Addressing concerns with magnesium oxide boards” (6 July 2021): https://ww3.rics.org/uk/en/journals/built-environment-journal/addressing-concerns-with-magnesium-oxide-boards.html
• The Building Regulations 2010, regulation 7 (England): https://www.legislation.gov.uk/uksi/2010/2214/regulation/7
• BSI, PAS 670:2021, Magnesium oxide-based boards for use in buildings. Specification: https://knowledge.bsigroup.com/products/magnesium-oxide-based-boards-for-use-in-buildings-specification
• Canadian Construction Materials Centre, MgO Board Advisory Update (1 March 2018), as published by the Saskatchewan Building Officials Association: https://sboa.sk.ca/ccmc-mgo-board-advisory-update/
• International Code Council, ICC 1125-2026: https://shop.iccsafe.org/icc-1125-2026-standard-for-classification-of-magnesium-oxide-board-and-construction.html
• N. Jays, A. Olofinjana, D. J. Young, “Assessing variability in the hygrothermal performance of magnesium oxide (MgO) cladding products of the Australian market,” Construction and Building Materials 203, 491–500 (2019): https://research.usc.edu.au/esploro/outputs/journalArticle/Assessing-variability-in-the-hygrothermal-performance/99450752202621
• Huseftersyn guide based on Almen Teknisk Fælleseje, “08. MgO-plader”: https://dev.sik.dk/sites/default/files/2020-07/08._mgo-plader.pdf