INSTALLATION GUIDE

Magnesium Oxide Board Installation Instructions

General handling, cutting, fastening and finishing guidance for Sulfycor magnesium oxysulfate boards used in wall, subfloor, panel and project-built assemblies.

Use this guide with the project specification
Board installation is assembly-specific. Confirm the board type, thickness, framing or substrate, fastener system, movement allowance, joint treatment, finish and required performance before work begins. Project drawings, local codes and approved tested assembly details take priority over this general guide.

DOWNLOADABLE TECHNICAL GUIDE

Installation & Handling Guide

Seven-page PDF covering board selection, storage, cutting, fastening, joints, application boundaries and final inspection.

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01 · BEFORE INSTALLATION

Select the Board and Confirm the Assembly

The generic term “MgO board” does not define an installation system. Surface finish, board thickness and end use change how the board is supported, fastened, jointed and finished.

Board familyTypical roleConfirm before installation
Non-Woven Finish MgO BoardWall sheathing, SIP facing, modular-wall structure and selected ductwork assembliesFrame layout, thickness, edge support, fastener schedule, membrane/cladding and required wall or duct performance
Sanded Magnesium Oxide BoardSubfloor, underlayment and specified structural floor systemsJoist or substrate layout, loading, span, thickness, edge support, floor finish and moisture management
Decorative MgO Wall BoardMelamine- or HPL-faced interior and modular-house wallsPanel dimensions, fixing method, trims, joints, exposed edges and cleaning/maintenance requirements

A board test result does not automatically qualify every thickness, finish or completed assembly. Match required performance to the tested sample or approved construction detail.

02 · STORAGE AND HANDLING

Protect the Boards Before Installation

  • Store boards flat, dry, under cover and clear of the ground.
  • Use level, continuous supports so the stack cannot bow or twist.
  • Protect faces, edges and corners from impact and point loading.
  • Carry large boards on edge with sufficient people or lifting equipment.
  • Do not install visibly wet, damaged, bowed or contaminated boards.

Tools, PPE and Dust Control

  • Tape, square, straightedge and pencil
  • Suitable scoring knife or carbide-blade saw
  • Drill/driver with controlled fastening depth
  • Safety glasses, gloves and suitable respiratory protection
  • Local extraction, HEPA vacuum or approved wet suppression

Do not dry sweep cutting or sanding dust. Follow the project safety plan, tool instructions and applicable safety data sheet.

03 · CUTTING AND LAYOUT

Prepare Clean Cuts and a Stress-Free Layout

  1. Inspect the board and confirm its intended face and edge condition.
  2. Support the board close to the cut and mark with a straightedge.
  3. Use score-and-snap only where the selected board and thickness permit it.
  4. Use a carbide-blade saw with dust extraction for thicker or precision cuts.
  5. Dry-fit boards before fastening; never force a board into an out-of-square frame.

Prepare the Supporting Construction

  • Confirm studs, tracks, joists or substrate are straight, level and securely fixed.
  • Support board edges, ends and penetrations where required by the assembly.
  • Plan joints around openings and avoid small unsupported strips.
  • Coordinate membranes, flashings, services, cladding and control joints.
  • For floors, confirm loading, span, flatness, bearing and finished-floor requirements.

04 · FASTENING

Match the Fastener to the Board, Frame and Exposure

Use fasteners compatible with magnesium oxysulfate board, the supporting material and the exposure environment. Wood and light-gauge steel require different thread and point designs.

CheckGeneral guidanceConfirm for the project
Fastener materialMatch the board, frame and exposure.Coating/stainless grade and corrosion category
Fastener layoutUse an orderly sequence that keeps the board flat and stress-free.Field/perimeter spacing and edge/corner distance
Fastener depthSet the head flush and secure; do not overdrive or crush the face.Whether countersinking is permitted
Board supportKeep joints and board ends supported where the assembly requires.Framing centers, blocking and joint orientation
Do not treat one spacing value as universal. Fastener spacing, edge/corner distance and gaps depend on board thickness, frame/substrate, application, exposure and required assembly performance.

05 · GAPS, JOINTS AND FINISHING

Treat Movement, Weather and Finish as Part of the Assembly

MovementProvide board, perimeter and control-joint movement allowances exactly as shown in the approved detail. Do not bridge structural movement joints with rigid board, tape or finish.
Joint systemUse compatible joint compound, flexible filler, tape, sealant or open-joint details selected for the board, finish and expected movement.
Weather and finishMembranes, waterproofing, coatings, adhesives and floor finishes remain separate systems. Follow their manufacturers’ instructions and prepare a mock-up where appearance matters.

06 · APPLICATION NOTES

Confirm the Complete Construction, Not the Board Alone

ApplicationInstallation prioritiesReview application
Wall sheathingFrame, thickness, fasteners, supported edges, membranes, flashings, cladding and wall performance.Wall sheathing →
Subfloor or underlaymentJoist/substrate, loading, span, thickness, support, flatness, moisture control and finished flooring.Subfloor systems →
SIP and modular wallsApproved factory drawings for facings, core, adhesive, pressing, joints, connections and openings.SIP panels →
Modular walls →
Decorative wall boardProtect the Melamine/HPL face; confirm fixing, trims, joints, exposed edges and visual approval.Interior decoration →
Fire-rated ductworkUse only the specified tested or engineered duct assembly; board classification alone is not duct-system fire resistance.Ductwork →

07 · FINAL INSPECTION

Check Before Covering or Finishing

  • Correct board type, thickness and face installed
  • Edges, ends and openings supported as specified
  • Fastener type, spacing and depth match the approved schedule
  • Required board, perimeter and movement gaps maintained
  • Damaged or wet boards replaced or reviewed
  • Joints, membranes, flashings and penetrations completed

Common Problems: Check the Cause First

Cracked edge: fastener position, overdriving, impact or unsupported board edge.

Visible joint: substrate flatness, joint system, curing and finish compatibility.

Recurring joint crack: frame movement, gap detail, control joint or rigid filler.

Fastener staining: fastener material/coating, moisture path and exposure.

Board distortion: storage support, moisture exposure, forced fixing or uneven framing.

INSTALLATION FAQ

Questions to Resolve Before Work Starts

Can MgO board be cut with a utility knife?

Score-and-snap may suit selected boards and thicknesses. Thicker or precision cuts normally require a carbide-blade saw with dust control. Confirm the selected product before cutting.

What fasteners should be used?

Use fasteners compatible with the magnesium oxysulfate board, frame and exposure. Confirm thread, point, head, length, coating and spacing for the project.

How much gap is required between boards?

There is no single universal gap. Board-to-board, perimeter and movement gaps depend on the application, thickness, framing, finish and approved assembly detail.

Does MgO board need acclimation?

Boards should reach the installation conditions specified for the project. Keep them dry and protected, and do not install visibly wet, damaged or distorted boards.

Can one installation detail be used for every application?

No. Wall sheathing, subflooring, SIP facings, decorative panels and ductwork are different assemblies with different support, joint and performance requirements.

Are board fire results enough for a fire-rated system?

No. A board classification applies to the tested sample. A wall, floor, SIP or duct must follow its specified tested or engineered assembly.

THE NEXT STEP

Request a Project-Specific Installation Review

Send the application, drawings or assembly description, board type and thickness, framing or substrate, fastening and joint requirements, quantity and destination.

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Application · Board · Thickness · Framing · Quantity · Destination

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