Updated Guidance for Magnesium Oxide Boards (MgO)

Published 8th April 2020 and Updated 16th April 2020

With effect from 15th April 2020, Premier Guarantee no longer accept the use of all types of Magnesium Oxide board (MgO) on any of our structural warranty schemes.

For any new scheme registered with Premier Guarantee, sites not commenced, or plots where foundations commence after this date, alternative products, which have an appropriate British or European Standard recognition, must be used.

Registered sites which are currently under construction with these boards installed, or are in the process of being installed, should replace these with alternative products where practical to do so. Where it is not practical to do so, or for new plots which are part of an existing block, clients should seek approval from their Risk Management Surveyor in relation to this.

We are aware that there are a wide range of MGO boards manufactured to varying quality standards and that there is a huge difference of opinion throughout the worldwide construction industry as to board acceptability. This includes how they should be viewed and tested. In the absence of a harmonised ISO EN, PAS or British standard, this material is reviewed as greater than normal risk. Our main concern has always been to protect our insurers and the end users or homeowners.


We are continuing to work behind the scenes with members of MOBBTA to gain a BSI PAS standard for Magnesium Oxychloride boards so that there can be trust in the industry for use of certified and tested boards that meet a certain minimum criteria.


We have been asked to consider the date and timescale of the guidance to allow the use of boards that met our previous standards, which were manufactured by Resistant and Euroform and have been awarded third party approval Multipro, Multi-pro XS and Multi rend (BBA 15/5255 PS1) and Versaliner (KIWA BDA BAW 18-085/01/A). Where these are used solely within the scope of the certification and in addition, for warranty purposes, not used as racking boards unless structural calculations are provided to justify adequacy.


Please be assured that we have given the surveyors transitional guidance and will work with suppliers and manufactures to ease in the new requirements.

Please be aware that this update replaces any previous guidance issued in relation to the use of MgO board. Failure to make changes as requested, may mean that we will be unable to continue to provide an offer of warranty cover.


Please Note: Every care was taken to ensure the information in this article was correct at the time of publication. Any written guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant Building Regulations or applicable technical standards. However, for the most up to date Premier Guarantee technical guidance please refer to your Risk Management Surveyor and the latest version of our technical manual.