Outer lining for FD30 frame

[Guest ShawJ]

Hi,

I am converting the rear half of my tandem garage into a utility room and installing a new FD30 frame and door into a new dividing wall in between the new utility room and remaining front half of the garage. This wall will be a stud partition wall with double skinned plaster board on both sides, one side with fire rated plasterboard as required by building regs. Because the overall thickness of this wall will be IRO 170mm, a standard sized FD30 casing is not wide enough to fill the depth of the opening. I am proposing to line the opening with ply wood or similar sheeting and install the FD30 casing within this, the question is: does this ply wood need to be fire resistant rated? The ply wood Wickes sell is 'Non Structural Hardwood Plywood'. Or should I be using another type of hardwood or solution?

I would appreciate any thoughts or guidance.

Thanks,

Jason

[Tom Sutton]

Using plywood, which IMO dosent have much fire resistant properties because the laminations would be exposed to a fire, I would use softwood timber, which is what the frame of a FD30 fire door is made of.

[Neil ashdown]

Detail below illustrates accepted method for door frame / lining extension to suit wider walls.  Generally, FD30 door frames may be softwood minimum density 450kg per cu mtr and for FD60 hardwood  640kg per cu mtr (at 15% moisture content).  Generally door fame thickness minimum 32mm plus the rebate stop by 70mm minimum width.

Hope this helps.