hi, any suggestion on how to cover a not-in-use real fireplace?d

malc_b

Why not just stuff up glass fibre or a combination of glass fibre in a black bin bag? As long as you stop up most of the hole it will work. A room needs some airflow anyway.

Also unless you put a lid on the chimney you get rain down it which will give damp. With a lid then it should be dry so only need a bit of air flow. If rain comes in you need a fair air flow to dry it out again.

keelydaye

Whether you put a screen in front of the fireplace or brick it up, you will need to allow for some ventilation at the base. At the top of the chimney you should also allow for some ventilation. If you are not planning on using the chimney again for along time, then do a Google search for a [ c-cap chimney cowl ] these prevent downdraft and rainwater but allow for suitable ventilation that prevents condensation.

If you think you might use the chimney again in the not-so-distant future then consider installing a Colt Top (or similar) multi purpose cowl, these also prevent downdraft but can be used with active chimneys too.