Blocking up fireplace

[Gorners]

Morning all - I’m going to be removing my gas fireplace and blocking up the hole soon. Once I’ve got a GSE to cap the pipe, just wanted to check opinions on my method after some research.

I want to block the hole up with thermalite blocks - my main question is, would you bother leaving a gap to put plasterboard on top of this and then plaster, or plaster straight onto the blocks? I wanted to do the former as this seems the ‘proper’ way of doing it but thoughts would be useful.

For the ‘plaster’, I was thinking of using Gyproc Easi Fix rather than plaster, given the small area - I’ve used this before on an area about 1/3 the size of this and it’s so easy to use and sands perfectly if required. Anyone think this is a bad idea?

Finally I’ll be venting the chimney under the floorboards, rather than into the room as don’t want a vent on show.

 

[CJRatch]

I'd board onto the blocks and skim the board. Thermalite would suck the life out of your skim.

You've covered the vent but also consider fitting a chimney cowl.

 

[cwhaley]

consider fitting a chimney cowl.

My advice would be definitely fit a chimney cowl, otherwise there's no ventilation for the inevitable dampness which will begin to accumulate in the chimney from the rain.

 

[Gorners]

Thanks for the replies, chimney cowl is actually already in place which is lucky.

Good shout on the moisture being sucked out the skim, is not thought of that.

Any serious concerns on going with Gyproc?