Suggestions for filling this gap please!

[RigidRaider]

Our chimney specialist has installed a double-skinned flue for an Aga. This runs right through the house from kitchen ceiling to roof. In the little room above the kitchen I have boxed it in using some shelving fixed at the required 2 inches away from the outside of the flue (see picture). This has left a gap in the floor as the weight-bearing plate is wider than the box.

We will be carpeting this room so I want to level this gap with something tough but flexible enough to resist movement due to heat and floor movements. Then the carpet fitter will glue the gripper rods to it. It also needs to seal the gap to prevent air being sucked in and rising inside the warm box, then out into the attic, which will eventually cause a dark stain as dust collects in the gap.

Any suggestions for a suitable filler/leveller?

 

[big-all]

take a strip of ply or wood the relivent thickness minus 2mm
grove as required for screws 'use heat resistant mastic as required to fix

is the metal frame fixed directly onto the joists!!!!

if it is i cant see heat transfer being a problem [unless its improperly fitted]

http://www.screwfix.com/app/sfd/cat/cat.jsp?cId=A336161&ts=84616

 

[RigidRaider]

Thanks. The metal will only be warm; the flue is double-skinned and insulated, then the weight is carried on three fins, which bear on this plate, which is also slotted a bit like a motorbike disc brake. Also it's only an Aga, not a coal or multifuel stove. So it will only be ambient warmth.

I'll take your suggestion and try 5mm ply bedded down on some "no nails".

 

[big-all]

i would avoid putting no nails in the area off the screws incase you need to gain accsess in the future for any reason

 

[RigidRaider]

Thanks for the advice, but those screws will have to be considered fairly permanent - this is the plate, which takes the weight of the whole flue, the bottom end being about a foot below this where it emerges from the kitchen ceiling looking like a rocket motor. Undoing these would only be possible if we had lit the blue touch paper and watched the lot heading off in the direction of the moon!

 

[masona]

A box skirting? It will make it looks proud and part of the feature?

 

[RigidRaider]

Good suggestion thanks, but I always feel that adding skirting to something like this only draws attention to it by outlining it.