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Steve Payne   

If you board your walls using MagO magnesium oxide board you can benefit by reducing many of the fussy requirements (of gypsum)

Canadian Contractor Fire

Peter Francis writes to us about the inherent stiffness and strength of MagO (magnesium oxide) boards, in place of gypsum. Let us know if you've used MagO boards - and how you and your client(s) liked the experience.

John Bleasby blogged on Wednesday about the time it took him and his carpenter to plan backing boards behind all the drywall areas where there were going to be heavy fixtures attached in his new home build.

Peter Francis from MagO building products, posted this comment about his firm’s products.

It’s basically an advertisement for MagO (we received no money for it – if we had, we’d mark it as a paid spot – and you’re doing your job well, Peter) but it’s still worth reading.

“There is an alternative. If you board your walls using MagO magnesium oxide board you can benefit by reducing many of these fussy requirements. This is due to the inherent stiffness and strength of MagO board. If you use 12mm board and wish to hang something you do not need to find backing or use plugs, one #8 screw into 12mm MagO will support 200 lbs in shear and most of that in tension.


MagO board joints do not need to be over a stud. MagO corners do not require corner bead. In addition every wall in effect has a one hour fire separation. (UL W-490);
the board is impervious to water, you can hose it down, if necessary power wash it

MagO is actively anti microbial, mold cannot grow on it due to the magnesium chloride (salt) content . It’s easier and faster to paint;  it’s possible to paint the same day as boarding and get a level 5 finish.
It’s easier and safer to work with; there are no VOCs, carcinogens or toxins of any sort. Magnesium oxide and magnesium chloride are both used as health supplements.

It’s not too expensive, with the labor savings that accrue from not having to be so fussy with prep. That – and faster finishing times – makes the installed MagO close to the cost of installed regular gypsum and perhaps cheaper than specialty flavors.

MagO is cut with carbide saws or score and snap. Using saws just makes for a cleaner better job with less or no requirement for tape and mud joints. Use a nail gun or any self counterboring screw, fast to attach. Use thinner lighter panels, 10mm is fine for most walls and 6 or 8mm for ceilings.

MagO is so strong that you could actually mount boxes for switches and receptables direct to the board and not to the stud (although this may contravene code).
At the end of your job, the scrap pieces of MagO can go to any landfill or, when crushed, it can be used as a soil amender as plants need magnesium to photosynthesize.

This is an evolution in construction, a brand new type of cement fiber board that has been around for 2,000 years in one form or another.”


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11 Comments » for If you board your walls using MagO magnesium oxide board you can benefit by reducing many of the fussy requirements (of gypsum)
  1. Ben Polley says:

    As an “alternative builder” (strawbale, Passive House, adobe floor & the like) we frequently test new-to-the market or even pre-commercialized products.

    We first experimented with magboard in 2008. My reply speaks to Magboard as a product category and may not specifically apply to the brand Peter carries. That said, I believe that most (all?) magboard comes from just a few factories in China so there is some chance that differently branded products are actually sourced from the same overseas facilities.

    Given this provenance, we must trust (as our own team currently do) that the product is indeed non-offgassing and/or doesn’t include toxic elements such as the widely publicized gypsum drywall from China that made it to the US market a few years ago. But I would argue that there may inherently be some risk in this regard when buying a product from manufacturers not affiliated with bigger, known north american brands.

    Then there is the carbon footprint of the heat energy and shipping used to make the product though I recognize this may not be of specific concern to all builders.

    In our experience a few points counter to Peter’s comments that do relate to builders:

    * MB joints that don’t end over a stud must be backed by another narrow strip of MB, glued and nailed/screwed to the main sheets. This is not less expensive/quicker than typical frame and board processes.

    *Beware fire rating claims. (In Ontario at least) Unless the manufacturer has acquired a BMEC number (or possibly a ULC or CSA approval) for their product it falls outside Part 3 or 9 of the Code; thus an engineer must sign off if it is to be counted toward total fire separation calculations. One learns this just once before being more cautious the next time.

    *Inclusive of shipping – which can be pricey and not always timely – we have found the material to be 2x to 4x that of GWB. There can also be more waste/offcuts as there are fewer stock dimensions available to suit natural wall lengths or heights, as we would ordinarily plan for with GWB.

    * Carbde blades are indeed required and you will burn through them pretty quickly Score and snap we have found to be all but impossible or at least impractical – MB as promised is dense and hard. Mostly though the need to cut boards means that the rapid fire pace at which GWB boarding takes place is not likely with MB. Consider it more like installing panel board ie. a role for a carpenter (thus slower work and at potentially higher wages).

    * Can’t imagine not taping joints, factory or otherwise. One brand suggests caulking then wiping the joints however we tried that too and it is all but impossible to get a flush finish. Some joints are harder to tape than GWB – the butt ends of MB need to be machined on site if you wish to chamfer them for taping…cannot simply run an exacto blade down the board as one might on GWB.

    *Overall we find the material cost to be higher than GWB, installation to be higher and mudding/taping to be marginally the same.

    One might think from the above that I am disuading MB use. In fact we continue to use it (doing so presently on a project in Ancaster, ON) but generally for specialized applications, where the limitations described above are minimal or where the advantages (paperless, strength, recycled material content etc as Peter describes) outweigh the other factors. If material costs were to decline substantially while also meeting regulatory norms (fire rating predominantly) of the local jurisdiction and offering more dimensions, there is no reason why it couldn’t be more widely applied.

    • Ben thank you for the well thought response. I think I agree with all you have to say. Currently we are promoting Magnum board which has UL, ULC, ICC certification and many other tests. Our fire assembly can be found on the UL site listed as W-490.

      Although we have not measured I would think that the extra care taken to install the boards with greater accuracy would be well offset by not having to return multiple times mudding and sanding and consider having the carpenters do the boarding, they are generally more used to working with saws.
      For score and snap with our board I find it best to use a disposable blade and score with several passes from the smooth side. You can check some of this out in a video on our web site.
      We hope to be making board in Canada within a couple of years so stay tuned and in touch.

      Thanks for permitting this forum, I appreciate it and your comments CC.


  2. Ron Voit says:

    Ben everything you have stated about the mag board that is imported from china is true thats why I started produceing mag board in the US that is not at all like the board coming from china. Its cuts and hangs just like gb and its lighter our 1/2 ” only weights 42lbs it also has a level 4 finish where the china boards they claim has a level 5 finish which is not true if you know what a level 5 is. Go check out my web site I am now working on dist into canada also we are working on the testing for canada.

  3. Jim says:

    I have been doing alot of repair work on mag board renos. It seems to me where all seams are but i am told they tape everything. Way too much cracking throughout renos. They blame temp change any info would help

  4. Kristina says:

    Do you guys have any information on MagO board installers in southern California? I’m building a house, would like to use it for walls and ceiling but it seems local contractors and subs have never heard about it and reluctant to install it. One said he would but wants me to indemnify him of all liability. I need someone experienced and who doesn’t fret easily. I’m going to put venetian plaster over it. Do you have any experience with how it would hold up?
    Thank you a lot

    • Avatar photo Steve Payne says:

      Hi Kristina:
      Unfortunately (wrong word) we are an all-Canadian magazine, print wise, although we dominate the world online ;). Anyone know of any Magnesium Oxide experts down in Southern California?

    • Peter Lassig II says:

      Hey Kristina,
      My contractor here in UT is an innovator and turned me on to MagO board. My shipment arrived last week and we’ll be installing it within a week or two. I don’t know what your time-frame is for building your home, but I could have him speak with you about it. Depending on your time-frame, perhaps he could even travel to CA to work with you on your project. He’s completely meticulous and is agreeable to all the wild ideas I have for the project I’m having him complete.

      I should add that he has never worked with the stuff, so I’m his first run. But I’m confident in his judgment and skill. I’d be happy to give you feedback about the project once it’s done.

  5. E. Perry says:

    I have years of experience with all North American board & finishing. Mag board is easier to work with then cement board (Durock or similar), but my experience is it is very brittle and cracks easily, as well as fasteners do not countersink easily ( similar to cement board). Due to cost & availability the Asian markets have been using Magnesium Oxide board quite a few year. They have experienced joint cracking issues and leave a gap between all joints & caulk them. This tells me that in our North American climate, we will experience more issues with the joints above the problems they have, as our temperatures fluctuation is much higher. Mag Board is far to brittle as well as not flexible enough to allow for expansion & contraction. The formula for MagO board needs further improvement to hold up & finish the joints in a long standing performance that is satisfactory. I presently work with the product here in Canada, but as an experienced finisher as well as being a carpenter, I see issues with the joints until the material has more flexibility & forgiveness

    • S. says:

      I love the product, but at this point, it is not really a suitable drywall substitute, in our experience, as E. Perry says. In our experience, when it gets cold, the board contracts – and unlike drywall, it doesn’t have any give, so it either pulls apart at the joints or it cracks in other places, like around windows and doors – either way, it’s unsightly. If you live someplace where it doesn’t get cold, this might not be a problem. I love the idea of MgO board replacing drywall – it takes less energy to make and it’s safe for landfills and it’s mold and insect resistant, etc. – but at this point, I don’t think it’s yet capable of replacing the smooth, seamless look of drywall. It would be worth trying in other applications, though!

  6. henk says:

    how have you to finishing the joints

  7. John says:

    I am planning do my basement. I am looking for a genuine. Could you please list few genuine Canadian suppliers?

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