Insufficient air bricks - is it possible to vent through chimney?

DRP

As the title says...

Our terraced house (c1901) has damp. The downstairs is smelly, with damp soil, damp joists, and wildlife (lots of slugs coming into the house, plus dreaded fungal growth on joists in the subfloor). We have dug out damp soil highspots under the floor but the ventilation issue remains.

The rear of the house has a large conservatory with concrete footings blocking 90% of the original house width - no venting was provided through this so only one small airbrick at the rear remains (back right hand corner of diner). The front lounge has 3 clear airbricks

In addition there are no gaps in the walls under the floor and no airbricks in the front hall - this is being remedied soon, but the single small airbrick is a bottleneck to rear ventilation.

One solution i thought of would be to vent the subfloor up through the chimney in this rear room. My idea was to break up the (unused and open) hearth enough to cement in a drain pipe or similar from the subfloor up into the flue - i could then box in front of the pipe within the fireplace to make it presentable.

Any pitfalls or experiences of trying something like this? Is it a ridiculous idea for some reason? Will I get sufficient 'draw' from the subfloor to make it worthwhile?

Any comments appreciated.

muckybutt

Not ideal I would say !

Doing that you will be introducing damp air into the chimney thus making the chimney breast prone to damp problems further down the line.

If you access the front of the house from the back under the floor you could run something like 4" pipe front to back and install vents to suit on the front of the house bringing in air and venting it that way ?