Water under floor when rains

[Toni1969]

Where do I start!!! We brought our little bungalow well chuffed with it until winter came.... I started having condensation really bad on my windows and under the bay window my wall was wet, we used a dehumidifier. we got the floor broads up and we have a 4ft drop and it was full of builders rubble bricks sand we moved this out of the bay has was told its bad to be in there plus taking like a sponge and drawing the water to it, we then put down a couple of inch bed on cement. We gave the wall the 1st coat of tanking in the Bay Area and rained heavy that night we still have floor broads up and we checked it water was coming threw I was gutted really thought this tank would be the answer to our problems we had been having.. We are going to do the tanking again 2nd coat.. Has anyone had this problem and how did you get around it? Any help would be very much appreciated has at the moment I'm at my wits end with it now.. I really thought it was to do with condensation and air flow until I saw the water run in ... My property is a 1930's bungalow with a aco drain fitted outside the property.

 

[ree]

Start by posting pics of the outside wall at ground level in the area affected, and pics of the underfloor area, and the inside of the bay.

Is there an access trap to the underfloor space somewhere else in the property?

Was the builders rubble from the original build or from more recent work?

Are you on a hillside?

Where does the ACO drain discharge to?

What did the survey report when you bought the bungalow?

 

[maltaron]

Water under a suspended floor is no problem at all. Damp in the wall is caused by a faulty damp course, no underfloor ventilation, or outside ground built up above the damp course. Check that the air bricks are clear of debris and the DPC in the bay. Sometimes bay windows were only half brick thick and damp can seep through. Also a 1930's property may not have cavity walls, just 9" solid walls and the DPC may be 2 courses of blue brick.

 

[ree]

"Water under a suspended floor is no problem at all." Water under a suspended floor can be a big problem - a very big problem.

In certain circumstances, airborne moisture can rise and rot out whole timber floors while creating massive condensation difficulties in the remainder of a house.

OP, I'm not saying that all, or any, of the above will happen to your house but what you describe requires attention.
Finding causes is the key to all damp and condensation difficulties.

 

[KenGMac]

Toni1969, hi.

Retro fitting a DPM to an external wall below ground will probably fail if the DPM is a liquid applied system out of a can from the local B&Q.

Even if the liquid DPM holds the water out of the properties under floor area, in severe condition's when the ground water rises because of heavy rain, or snow melt, the water will find its way in under the eternal wall to enter via the Solumn itself, unless there is a DPM under the Concrete you have placed on the Solumn then the concrete will be of little assistance in keeping the water out.

more questions?
1/. Are any of the external underground drains in the area of the bay?
2/. Any very, very wet areas externally on the surface of the ground near the bay?
3/. Any other areas of water getting into the Solumn in other areas of the Under floor?

There are a couple of firms that will pitch up, take samples of the water in the under floor and test for the presence of
A/. Soap, this could indicate a damaged / leaking underground drain
B/. Faecal material, a damaged Sewer.
C/. The water may turn out to be clean Ground water?.
But these services cost.


One expensive retro fitted DPM System is SIKA who do have materials and the expertise to make the wall dry internally.

Ken

 

[theprinceofdarkness]

It is most likely that the downpipes from your gutters do not terminate properly. They should either go into a trapped gulley (drain) or run into a pipe that is buried and runs away and down hill from the property by 15 feet or more.
I am sorry that you moved all the rubble. It does not "draw" in water, on the contrary, if the void was filled to within 6 inches of the DPC and THEN tanked/covered in concrete, as the concrete was above the water level, you would never know the water was there.
You can get underground springs that only appear in winter due to the increased amount of rain. What is the general ground like around you?, hilly or flat, clay subsoil or chalk?
I worked in Upper Norwood in south London. It sits on a ridge that is 1/2 mile long with the highest point on the Parade at Crystal Palace, then a gentle slope to where we worked then a 200' drop in 1/4 mile down to South Norwood. The building was new and built on a concrete raft, but in winter we used to have water running in our cable ducts about 18" under the floor level!!
Frank

 

[ree]

theprinceofdarkness,


The existing void is four feet deep, the builder's rubble would typically be scattered near the foundation walls.

You are proposing to bring on site a large amount of further rubble or hard core and fill the 1.2m void to within 6" of the DPC and then concrete over.

How would you install this 4ft of rubble across the whole house suspended floor footprint? And then lay a bed of concrete on top in the available void space?

Would you propose to lift all the suspended floors in the house?

Given the instability of the un-tamped hardcore, and the continued activity of the water below, what happens down the line if the concrete layer begins to crack etc?

 

[KenGMac]

Ree, hi

I have been faced with this almost exact scenario?

A fuel oil tank was tipped over by a flood.
The kerosene flooded into the under floor area of a property in a remote area of Scotland, near a Nuclear Sub Base.

The kerosene effectively totally stripped the liquid applied DPM from the concrete of the Solumn

I authorized a system where a pumped fluid Concrete was placed into the Solumn it is an aerated material that was placed into the under floor area to a level that was above the flood level of the kerosene, we then applied a layer of bitumen sprayed DPM to make the Solumn damp free or nearly so?

The Kerosene totally stripped the original liquid applied DPM, that is what it does, and when I say stripped the DPM, the original Concrete over site was stripped bare of the Liquid Applied DPM

The Concrete placed was a so called Foam Concrete that is so fluid that it is self levelling, you can when the Concrete is still wet wade through it?

We placed this material to a level just above where the original liquid applied DPM had been,

The Foam Concrete was delivered to site and placed using the delivery trucks own on board conveyor system.

Not cheap, but effective?

The Foam Concrete was well below the Air bricks in the external walls, drawback was that the depth from ground floor to Solumn was reduced from about 1.5. M to 600.MM.

Ken

 

[theprinceofdarkness]

In 1981 , I was forced to sell a house to a housing "action area" Mafia. The Council had decided that the house needed upgrading and I could not afford to do it. One of the things that they insisted on was that the suspended floors were replaced by solid floors. I used the under floor area as an electronics workshop in an identical house next door!! So there must be a way. But it would seem to me, the last resort.
You have not commented on my questions. If your bungalow is sitting in a bowl of clay, this is why you will get water under the floor and unless you bring the tanking level above the highest water level on all surfaces including sleeper walls, water will find its way in. The problem with this method, is that you only need a pin hole, water will get in and not get out and will stagnate during the summer.
Your say the bottom of your void is four feet deep, all you are trying to do is to stop water vapour (gas) in winter and the smell of stagnant water (summer) percolating up through your floor boards. So you need a horizontal vapour seal above the maximum water level , also it would be good to have it below your airvents and wood work. says it all, building block here and there (or builders rubble), VCM battened to wall, bit of silicone gunk and tape.
I might have missed the point, but I do not think you said if the water is coming through the walls or appearing from the deck.
Frank

 

[ree]

princeofdarkness,

You've not just missed the point, you've missed the bus.

Ignoring all the blather you fill your posts with, i asked you above -
1. how do you propose to fill the sub-floor area with rubble?
2. and how do you propose to form the layer of tanking concrete?

Now, without answering the above questions, you shoot off with a scheme for erecting some kind of tent in the sub-area.
Are you Heath Robinson in disguise?
Would the tent erection take place after you had dug out all the rubble you'd originally filled the void with. Snow White had her dwarfs - who is going to go mining with you?

This after your original certainty (based on no evidence at all) that the problem was: "most likely the downpipes not terminating properly"

What nonsense, so beyond rubbish that possibly or luckily no OP will be acting out your fantasies.

 

[maltaron]

Ree, I am surprised that you rubbished my comment about water under the floor is no problem, yet not once have you mentioned air bricks. Providing that there is a clear flow of air through the void there is unlikely to be a problem with water in the bottom of the void. In the past I have both owned and worked on many pre and post war houses with this same problem, and all have been cured by clearing the air bricks of debris. The major problem with lack of air flow is of course dry rot.

 

[ree]

Malatron,

First things first.
Find the cause then prescribe a remedy.
The actual issue is water on the oversite - the key clue to possibilities is the OP's mention of an ACO drainage in-situ.

If its necessary to deal with vents it can come later - a 4ft deep void implies a minimum of air space.

FWIW: you also claim that "Damp in the wall is caused by a faulty damp course"
How do you know? We dont know where the water is coming from.

AAMOI: I never encountered a faulty damp course - slate, bitumen, felt or plastic - not one. Many others with far more experience and professional qualifications than me have had the same result when going forensic over a DPC. Rising damp was always coming from bridging of some kind, not from a faulty or "cracked" DPC.

 

[Toni1969]

Hello thank you for all the replies, my bungalow is at the bottom of a slope our rd goes downwards then my bungalow is roughly 2-3ft from down from the road.. I will post pics later for you the down pipes have all been checked and cleaned out.. The drainage well that's another thing I can't reply to this. has the previous owners had the concrete print on the front garden so all I cane tell you about the aco drain goes to the drain in the drive way but where it goes after that is another thing and the drain from the guttering I don't know where that goes ether.
The air bricks was blocked in the bay put air bricks in but under the floor broad the brick was blocking the air brick so was only one air brick under the living room.. Got 2 air bricks now other being done this afternoon so there be 2 in the bay part and one on the side wall
All the rubble was removed and put into a skip I don't know when or where the rubble came from.. But it was all damp its now in a skip anyways...
Also yes I have solid walls no cavertly walls
I will post pics later to explain more of this very anorning situation

 

[maltaron]

I would suggest that you rather short on air bricks. You need a minimum of one every 2 metres on all outside walls, and normally bricks are left out at intervals in the sleeper walls and any dividing walls.

 

[Guitar_man]

This is an interesting topic, so i thought i would ask a similiar but slightly off topic question.
If you beleive that damp and water affecting your property is coming from a council gutter in poor repair at the side of your house are the council oblidged to a repair or replace the gutter (half moon concrete) with something better, ie a ACO drain?
Having spoken to them im unsure what there responsibilities are if they try to fob you off.
Cheers,