Water under my bungalow

youth_leader

Yes Bendy_House, I did feel the solum on a rainy day.  With the limited view I had in the rotten floorboard bedroom, I couldn't see any rain coming in/water running. 

This floor business has been a shock to me and I am a bit confused, but I remember now that this all started when I was sleeping in the back bedroom, and the front bedroom windows were dripping with condensation. I did buy a dehumidifier not realising it would only service one room and put it in the front bedroom, it was collecting 10L per night.   The floor problem hadn't revealed itself yet.  My purchase surveyor recommended a Nu-Aire system in the loft.

I'm gearing up to cut the carpet and clean the chipboard in readiness for the big hole cutting.

The extension is surround by 10p sized gravel, I've just dug it away in front of one of the airbricks.  The gravel is about six inches deep and there is a weed proof black membrane at the bottom.  

Thank you all very much for your support and suggestions.  I will report back when I've made/had further investigations.  

Bendy_House

Windows dripping with condensation can be treated using the same method - open the windows and allow a draft through :-)

It might seem connected - and it could be to some extent, we don't know - but I'd personally be reluctant to attribute the condie windows to the other issue.

To cut to the chase, if ANY house with an underfloor void had its ventilation compromised, then I would EXPECT damp issues and ultimately rot. 

What impresses me about your house is how MANY vents it has - far more than mine, for instance - so I'm speculating that this was done as the builder KNEW this was naturally wet ground. IE, a good move.

It's interesting that the seeming reason why some floors were concreted was due to woodworm, and not rot. If this is true, I think we can surmise that the vents WERE doing their job - until a builder poured a shedload of concrete.

You don't know when this was done? Or who did it?

DRP

I had a terrace house with very damp soil under the floorboards. 

We also had very high humidity within the house, and some issues with condensation (not as bad as yours sounds).

we ‘fixed’ it by putting in a concrete floor and tanking the problematic wall.

Bendy_House

On the issue of some vents seemingly being above floor level - weird - my mil's new bungie - circa 2008 - also has vents above floor level, but she has solid floors and UFH. So hers must be serving the wall cavity, and yours might be too. IE, you could have TWO types of vent bricks. The summat soft is likely to be cavity insulation?

ARE the vents at two different heights?

theoretica

If the property has been standing since 1938 I would be *very* surprised if it has had this issue all along - it would have gone through umpteen replacement floors.  So I think the question is 'what's changed' and that also points to the extension and concrete floors.

Bendy_House

GDB2222 said:

If the problem is actually insufficient ventilation, then adding mechanical ventilation (it’s just a fan) may well solve the problem as well as the symptoms. It’s also vastly cheaper than the other suggestions, and there are systems designed for this issue.

https://www.tlc-direct.co.uk/Products/VAPAH.html?source=adwords&ad_position=&ad_id=454654373914&placement=&kw=&network=u&matchtype=&ad_type=&product_id=VAPAH&product_partition_id=957814854954&campaign=shopping_8_Percent&version=finalurl_v3&gclid=Cj0KCQjw_4-SBhCgARIsAAlegrVSQQjZtvC7gOX27lHpHFD35gYSClIwSoFRUVszR3NrWdXpbaJFjUkaAuCIEALw_wcB

I hope the link works. It’s just a fan system costing under£300 from a well known brand.  The op might well need more than one, but I doubt that the work would cost more than £2k say. Or, she may need some entirely different system. 

As long as it solves the problem, it is what I would probably do, but at the moment we are just assuming the problem is poor ventilation.

Pouring a new concrete floor may also work well, but it’s likely to be more expensive and much more disruptive.

That's a lot cheaper than I imagined, GDB. I just hate the idea of a fan permanently running to do a job that should solved 'properly'. But that's daft of me, as it makes sense as a perfectly acceptable solution.

GDB2222

Bendy_House said:

GDB2222 said:

If the problem is actually insufficient ventilation, then adding mechanical ventilation (it’s just a fan) may well solve the problem as well as the symptoms. It’s also vastly cheaper than the other suggestions, and there are systems designed for this issue.

https://www.tlc-direct.co.uk/Products/VAPAH.html?source=adwords&ad_position=&ad_id=454654373914&placement=&kw=&network=u&matchtype=&ad_type=&product_id=VAPAH&product_partition_id=957814854954&campaign=shopping_8_Percent&version=finalurl_v3&gclid=Cj0KCQjw_4-SBhCgARIsAAlegrVSQQjZtvC7gOX27lHpHFD35gYSClIwSoFRUVszR3NrWdXpbaJFjUkaAuCIEALw_wcB

I hope the link works. It’s just a fan system costing under£300 from a well known brand.  The op might well need more than one, but I doubt that the work would cost more than £2k say. Or, she may need some entirely different system. 

As long as it solves the problem, it is what I would probably do, but at the moment we are just assuming the problem is poor ventilation.

Pouring a new concrete floor may also work well, but it’s likely to be more expensive and much more disruptive.

That's a lot cheaper than I imagined, GDB. I just hate the idea of a fan permanently running to do a job that should solved 'properly'. But that's daft of me, as it makes sense as a perfectly acceptable solution.

I agree with you. I hope  @youth_@youth_leader investigates what's wrong thoroughly. Making lots of decent size holes in the floors, for as long as it takes, so as to be absolutely sure what the issue is.

It might be a burn or field drain, but that would be bad luck for it to come up just under the foundations. 

youth_leader

I've just been alerted to 'periscope' air vents on Google, perhaps mine are this style and that's what I'm hitting? 

The concrete floored extension was built in 2002, retrospective approval was given in 2007. I'd forgotten I had the plan saved and have just looked at it, but it is a general plan for tender, unfortunately no builder is named on it.  Several things mentioned on it haven't been done, ie the extension windows don't have trickle vents.

The previous owner purchased in 2012, and had the floors replaced with chipboard on the left of the bungalow, as well as the hallway and bathroom floor,  in 2016.  I did contact her when I discovered the mould and asked for the history of the floors - she said the company she engaged recommended full floor/joist replacement and she also moved out,  it was for woodworm.  Unfortunately this company went out of business in 2018 so I can't find out any more.  I moved in here in March 2021.

A friend who also wanted this bungalow congratulated me when she heard I'd got it - but warned me she had smelled damp. 

I hope I can see something when I open up the floor.  

GDB2222

youth_leader said:

I've just been alerted to 'periscope' air vents on Google, perhaps mine are this style and that's what I'm hitting? 

The concrete floored extension was built in 2002, retrospective approval was given in 2007. I'd forgotten I had the plan saved and have just looked at it, but it is a general plan for tender, unfortunately no builder is named on it.  Several things mentioned on it haven't been done, ie the extension windows don't have trickle vents.

The previous owner purchased in 2012, and had the floors replaced with chipboard on the left of the bungalow, as well as the hallway and bathroom floor,  in 2016.  I did contact her when I discovered the mould and asked for the history of the floors - she said the company she engaged recommended full floor/joist replacement and she also moved out,  it was for woodworm.  Unfortunately this company went out of business in 2018 so I can't find out any more.  I moved in here in March 2021.

A friend who also wanted this bungalow congratulated me when she heard I'd got it - but warned me she had smelled damp. 

I hope I can see something when I open up the floor.  

Just open up lots of inspection points, then decide what to do. Understandably, you are worried, but you need to see what's wrong before acting.

You may also want a different surveyor, for a second opinion.

FreeBear

Bendy_House said: - my mil's new bungie - circa 2008 - also has vents above floor level, but she has solid floors and UFH. So hers must be serving the wall cavity

Could it be a block & beam floor with a void underneath ?

It would have all the appearances of being a solid concrete floor - Shoving a camera through one of the vents might reveal more. Unlikely they would have put a vent in to ventilate the cavity as it should be stuffed with insulation.