Update, suspended floor suprise

[Dave55]

Thanks to everyone for your advice on my initial post, I have got out all the rubble from under the joists and I am left with the room as in the pic, I am looking to put a dwarf wall of a single concrete block on a 150mm footing with a 25mm wall plate on top down the left hand wall and opposite along the fireplace wall with a sleeper wall in the centre of the room and use 47 x 125 treated C24 timber joists at 400mm centres, which will have a minimum of 150mm air gap below.
Any thoughts on the ventilation system I am looking at trying would be greatly appreciated as this is my first time at this and I would like to get it right first time.
Thanks in advance, Dave

 

[DampedOut]

Following with interest

 

[88v8]

Gosh, this has escalated...

Not easy with stone walls 2 foot thick.... Depending on external ground levels I would get the wall diamond core drilled for air vents under the floor. Preferably two front two back, but the more the better and as I see there are solid floors in the way you may have to settle for vents at the sides.

Cast iron grilles are available for the period look, do not use terracotta as they have little free area.

Your dwarf walls should be honeycomb so as not to impede airflow.

Ivor

 

[Dave55]

Gosh, this has escalated...

Not easy with stone walls 2 foot thick.... Depending on external ground levels I would get the wall diamond core drilled for air vents under the floor. Preferably two front two back, but the more the better and as I see there are solid floors in the way you may have to settle for vents at the sides.

Cast iron grilles are available for the period look, do not use terracotta as they have little free area.

Your dwarf walls should be honeycomb so as not to impede airflow.

Ivor

Yep it sure has
The problem is the external floor level on the front solid wall is 50mm higher than the internal finished floor level.
Dave

 

[Matt Green]

Dealing with the cause rather than the symptoms?! Bravo!

 

[RBailey]

Curve ball warning.
Have you thought about a crushed glass / limecrete solid floor?

 

[Dave55]

Curve ball warning.
Have you thought about a crushed glass / limecrete solid floor?

Hi Richard, yep I'm thinking I may go down that route

 

[Roger440]

Hi Richard, yep I'm thinking I may go down that route

Was this suspended timber before? Doesnt look deep enough.

As previous post, foamed glass and limecrete? Jusyt done mine. With UFH. Very very happy.,

 

[Dave55]

Was this suspended timber before? Doesnt look deep enough.

As previous post, foamed glass and limecrete? Jusyt done mine. With UFH. Very very happy.,

The joists were sat in amongst a rubble/scalpings type base and completely rotted, it was odd as there are two air vents adjacent to each other?

 

[Sam W]

On air vents - we have a similar set up. External ground level higher than internal, thick stone walls, preference would be to lower externally but this is not possible.

I've added air bricks by starting above ground level outside and drilling down to come in under the floorboards inside. Walls are about 2ft thick, it's obviously hard work going through them, but does have the advantage of allowing a relatively shallow gradient hole.

The added air flow has been successful in reducing damp. Far drier under the boards although wall plates and joist ends do still hold a little bit of moisture. The musty smell in the rooms above the floor board has been completely eliminated.