Suspended floor confusion

[DaveG]

Hi all, I’m trying to get my head around how air should move under subfloors between rooms in my circa 1870s stone house. The problem I have is if you imagine a typical layout of central hallway with rooms leading off both left and right, the hallway I’m pretty sure is suspended floor as it still has original Victorian clay tiles and near the bottom of the staircase there’s a small gap in the tiles of which there’s cavity underneath.
Both reception rooms from the hallway left and right must have also originally been suspended (evidenced by air openings outside front wall) but have now been filled with concrete. This I think has resulted in the remaining suspended hallway floor in the middle of the house being left with no means for moisture to escape and when I look around the base of the stair posts they look like they’re rotting. Also there’s damp smell underneath the stairs cupboard despite the cupboard itself being well ventilated.
I’ve decided to return one reception room on one side of the hallway to suspended timber floor, thinking this would at least start to introduce fresh air back to the hallway subfloor and I’d eventually tackle the room on the opposite side to improve airflow but having dug down directly from the door threshold, there appears a solid wall between hall and reception room. I’ve only so far excavated about the width of the door about 2ft back into the room to around 12 inches in depth.
I don’t really know what I was expecting but I mistakenly thought this would enable me to look across, beneath the hallway floor however stone wall is in the way.
Is this just because it’s a doorway and if I excavate along the wall there will be gaps or is it that I’ve not gone down deep enough yet?

I hope this makes some sense but basically trying to understand if there’s low stone wall around the perimeter of each room, how can air get across? Is it through more vents as opposed to what I thought which was that it was much more open between rooms below the floor?

 

[Lacan07]

Hi all, I’m trying to get my head around how air should move under subfloors between rooms in my circa 1870s stone house. The problem I have is if you imagine a typical layout of central hallway with rooms leading off both left and right, the hallway I’m pretty sure is suspended floor as it still has original Victorian clay tiles and near the bottom of the staircase there’s a small gap in the tiles of which there’s cavity underneath.
Both reception rooms from the hallway left and right must have also originally been suspended (evidenced by air openings outside front wall) but have now been filled with concrete. This I think has resulted in the remaining suspended hallway floor in the middle of the house being left with no means for moisture to escape and when I look around the base of the stair posts they look like they’re rotting. Also there’s damp smell underneath the stairs cupboard despite the cupboard itself being well ventilated.
I’ve decided to return one reception room on one side of the hallway to suspended timber floor, thinking this would at least start to introduce fresh air back to the hallway subfloor and I’d eventually tackle the room on the opposite side to improve airflow but having dug down directly from the door threshold, there appears a solid wall between hall and reception room. I’ve only so far excavated about the width of the door about 2ft back into the room to around 12 inches in depth.
I don’t really know what I was expecting but I mistakenly thought this would enable me to look across, beneath the hallway floor however stone wall is in the way.
Is this just because it’s a doorway and if I excavate along the wall there will be gaps or is it that I’ve not gone down deep enough yet?

I hope this makes some sense but basically trying to understand if there’s low stone wall around the perimeter of each room, how can air get across? Is it through more vents as opposed to what I thought which was that it was much more open between rooms below the floor?

Typically youd knock holes in interior walls to allow air flow from one side of the house to the other but sometimes you may this was neglected.

 

[Cubist]

You need to remember that in the typical layout the two walls on either side of the hall are load bearing and will be carrying some/most of the weight of the stairs, landings and rooms on the upper floors. Those walls are often solid brick down to the foundation and only if the builder was aware of the problem would any openings be left to allow air-flow. Wooden suspended floors would often be installed on joists resting on and inset to the walls in both the hall and the adjoining rooms.

The only way to find out for sure and decide what, if anything, needs to be done is to lift some of the floorboards in the hall and take a look.

 

[DaveG]

Thanks. Having excavated a little more today I’ve found what I think is a sleeper wall about 3 ft into the room but I’ve only gone across the room in one direction about 2ft back from the wall. Will gradually excavate more but getting rid of all the material is the most difficult part so it’s going to have to be a slow burner task.
One thing I am excited about is I got to a blocked up iron subfloor vent which I’ve now cleared of debris.
It’s not at all central to the room, almost in a corner. The room is approximately 3.5m x 3.5m. Do you think I should be going to the effort of adding another vent on the same wall in the far side of the room? I’d imagine it will be no small task on a stone 3ft thick wall but ventilation is important. Alternatively should I look at some sort of fan unit to active move air around and then the one vent could be enough on that wall?

I realise this would be much better with pictures. What picture hosting sites are people using?

With regards to the hall, the problem is it’s still covered in original clay tiles. Must be 20mm thick so a lot to disrupt and potentially try to salvage.
Through the small hole at the base of the stairs though, poking through reveals quite damp earth barely an inch underneath so I guess at some point this floor will give way

 

[a twig]

You can upload straight to the forum if you are happy to do so, no need for an image hosting service.

Fans are an option but then obviously need access for maintenance, there is noise etc. Passive ventilation is definitely preferable if it can be achieved.

 

[Lacan07]

you can never have too many air bricks

 

[LadyArowana]

you can never have too many air bricks

Are you absolutely sure about that?

 

[DaveG]

I was thinking the same thing!

 

[DaveG]

Let’s try this picture attachment thing.
Progress so far just doing an hour after work each day:





The vent is just to the left of the spade in the first picture