Water under suspended subfloor void

[Adam78]

Air flow is vital to prevent rot and smell. The kitchen areas in 1930s houses were usually concreted but even in those days the sub-floor void of the suspended timber floors was usually ducted through the concrete to an outside wall. Are you sure there are no vents covered over? Or maybe the floor was concreted more recently by somebody that didn't install vents? Either way, a solution would be to cut through the concrete floor and install ducts/vents. It just depends on the layout of kitchen and what disruption that might cause? Ideally you'd have three vents.

The water is a different problem. More houses than you think have excessive water under them which isn't evident because of good ventilation. If you solve the ventilation issue you may find the water issue recedes sufficiently to not be a major problem. If it remains an issue you will need to find some way of creating a drain. There are only really two options - gravity or pump. From your description it sounds like you would struggle to get a gravity drain in? Alternatively you could create a sump with a sump pump discharging to a mains drain. It's not as difficult as it sounds and loads of buildings have them.

The vent issue is an issue regardless of the water so I would tackle that first and see what happens.

Would fitting a french drain outside the house help as the house is on a slope?

 

[Mr Chibs]

Depends on where the water is coming from, do the dye test to see where the problem is, then you can look at fixing it.

 

[jeds]

Would fitting a french drain outside the house help as the house is on a slope?

That could work - as long as the french drain actually drains. If your water table is that high, chances are it might just fill with water itself.

 

[tomlat]

I have a 1915 house with a suspended timber floor and a relatively deep sub-floor void – roughly 3 feet from the underside of the joists to the soil. After periods of heavy rainfall, water enters the void and can pool to a depth of around 5 inches beneath one room. There is a floor hatch so I can see this happening.


The area beneath the hatch appears to be the lowest point in the house, as water always shows up there first and will spread further if the rainfall is more severe. I carried out a dye test by pouring dye at the corner of the house, and it does eventually appear in the void a few hours or even days later, depending on how much additional rain there is.


I can’t see any obvious defects in the timbers at present, and I don’t know how long this has been occurring, but they currently appear sound. There are two air bricks on the affected corner and several more serving the sub-floor void, which only exists at the front of the house (the rear has a concrete floor, for reasons I’m unsure of).


When the weather is dry, the water gradually dissipates and the void dries out after around 10 days to two weeks.


My question is whether this is something I can reasonably monitor, or whether I should be looking to prevent the water ingress altogether — and if so, how best to approach that. Ultimately, I’d just like to understand whether this is a common, manageable issue or something that needs more urgent attention, as I’d really like to stop losing sleep over it.

 

[Harry Bloomfield]

My question is whether this is something I can reasonably monitor, or whether I should be looking to prevent the water ingress altogether — and if so, how best to approach that. Ultimately, I’d just like to understand whether this is a common, manageable issue or something that needs more urgent attention, as I’d really like to stop losing sleep over it.

It will, in time, rot your floor timbers, so best to solve it. A quick fix, is to form a sump, and install an automatic pump, to drain the water. Longer term, you need to have the water analysed, to check whether it is rain water, ground water, or fresh tap water, then work from that. If you have a water meter, that might prove whether you have a mains water leak.

 

[JohnD]

I have a 1915 house

50p says you have a gulley serving a gutter downpipe, that has been cracked or broken since 1940.

It is made of brown glazed fired clay and you need to dig it out and fit a replacement. The pipe in the ground may also be broken, usually at the bend where the horizontal pipe turns upward towards the gulley.

It is not a complex or difficult job if you can handle a spade. Modern plastic replacements are very light.

Probably all the drains round your house are broken in the same way.

I am told there is an old house in England that does not have a broken gulley, but I have never seen it.

 

[tomlat]

It will, in time, rot your floor timbers, so best to solve it. A quick fix, is to form a sump, and install an automatic pump, to drain the water. Longer term, you need to have the water analysed, to check whether it is rain water, ground water, or fresh tap water, then work from that. If you have a water meter, that might prove whether you have a mains water leak.

Thanks for the reply.

I have had a surveyor provide a report and advised that the void is acting as a natural soakaway and is actually done by design given how deep it is. I think you get conflicting views wherever you look on this type of thing.

50p says you have a gulley serving a gutter downpipe, that has been cracked or broken since 1940.

It is made of brown glazed fired clay and you need to dig it out and fit a replacement. The pipe in the ground may also be broken, usually at the bend where the horizontal pipe turns upward towards the gulley.

It is not a complex or difficult job if you can handle a spade. Modern plastic replacements are very light.

Probably all the drains round your house are broken in the same way.

I am told there is an old house in England that does not have a broken gulley, but I have never seen it.

I have had all of the gullys replaced in the last few months as i thought this could be the problem but it isnt!

 

[JohnD]

Where shall I send the 50p?