Rising damp through concrete floor?

[Gimpymoo]

So, having had some plastic backed dust sheets down for a while, I go to move them today and find droplets of water on them in some areas, quiet a lot to be fair.

This has been ontop of carpet.

We have a concrete floor.

House is circa 1907.

Looking at the edges of the room behind skirting board, I can see some blue pastic stuff, could this be a membrane which has failed?

What are the solutions, rip up the floor at likely high cost and mess no doubt and apply membrane and concrete over?

Honestly, this house becomes more like "The Moneypit" every day

 

[Nathan]

Unfortunately in my parents experience they had to rip out the floor.

The property they live in once had suspended floors which were filled circa 1980.

They tried everything, insulated plasterboards on exterior walls, better heating etc and still found damp at the edges. Ripped it all out and put suspended floors back in, damp now gone!

 

[Gimpymoo]

It is probably the inevitable.

I can do some of the donkey work myself like digging up old floor etc.

From what I can see, most DMP's will last about 20-30 years? We have no plans on moving so ideally would like something which will last longer.

Looking at something like this:

http://www.screwfix.com/p/damp-proof-membrane-1200ga-black-4m-x-25m/47163

Dig out to earth, lay that down, then lay new concrete floor on top?

 

[Scrutinize]

You may be surprised how much water you can get from condensation alone especially in an old house. It can look like penetrative damp as well.

Rising damp doesn't really exist per-se and it is always driven by an underlying problem wether a leak from the roof, under floor pipe, window, conservatory, breached cavity, no cavity, high water table and no effective DPM etc.

No need for expensive floor work initially. If you have bare concrete to work on then do two coats of this on a 1sqm area.

http://www.screwfix.com/p/sika-waterproof-coating-grey-5kg/83502

This works very well. Put the carpet back then if after a couple of weeks there is water on top it means condensation, no water then it can be penetrative damp/water.

In old houses the bitumen tile adhesive and Marley tiles often formed the DPM. These are usually long gone.

You don't always need to dig up and replace floors either. You can tank, then lay a water proof concrete screed on the ground floor. Depending on situation this could be 10mm-50mm. You can tank up the walls as well if needed but will have to remove plaster to do this. As little as 6" is sometimes enough.

Unfortunately too many so called damp specialist miss diagnose for money.

A proper chartered surveyor and good builder can often fully diagnose for £250-500.

 

[Gimpymoo]

I can see some "blue plastic" behind some of the skirting which is about 1½" - 2" below floor level, I assume this is an old damp proof membrane?

 

[ANDARIAL]

I can see some "blue plastic" behind some of the skirting which is about 1½" - 2" below floor level, I assume this is an old damp proof membrane?

sounds like it,this will go under the floor and is tucked up the walls about 4 inches
Is it damp under the carpet?
Pull up carpet and inspect,maybe get a cheep damp meter and see what it reads
EDIT: No-one spilled any water recently did they?
What work was carried out?any water based painting going on?

 

[Gimpymoo]

What work was carried out?any water based painting going on?

Yes, some watery fresh plaster paint

Nothing spilt on the carpet BUT something which has bugged me for a long time is the floor has always been cold and any liquid spillages on the carpet always seem to take a while to dry and even then, never feels bone dry for ages.

Am going to get a damp meter and see what it reports.

Will pull up the carpet/underlay and see whats what. If there is a damp problem, I suspect will be nice and mouldy.

Carpet has been down for around 10 years.

If I have to rip the floor up, underfloor heating is going in.

 

[Skiddley]

We have a 1913 house, concrete floor measured at an unacceptable moisture level for a new floor to be laid (Karndean). Fitter applied an Ardex Liquid DPC. No issues to report since.

EDIT: This is the stuff; http://www.ardex.co.uk/ProductDetail.aspx?ProductID=14

We used a latex SLC screed over the top.

....when I say there were no issues... other than my dog getting into the room and walking over the final coat of screed that is

 

[Gimpymoo]

Fitter applied an Ardex Liquid DPC. No issues to report since.

EDIT: This is the stuff; http://www.ardex.co.uk/ProductDetail.aspx?ProductID=14

We used a latex SLC screed over the top.

....when I say there were no issues... other than my dog getting into the room and walking over the final coat of screed that is

Ooooh.

Thank you.

That looks like just what we need. Saves ripping up the floor. I assume you have to rip off the skirting board to get all the way under else the damp will just go up the walls?

Thing is, we have some really high original skirting board which is a pain in the butt to get now but needs must.

Would you say it is a "DIY" job?

What did you say to the dog? And what was their response?

 

[Skiddley]

Ooooh.

Thank you.

That looks like just what we need. Saves ripping up the floor. I assume you have to rip off the skirting board to get all the way under else the damp will just go up the walls?

Thing is, we have some really high original skirting board which is a pain in the butt to get now but needs must.

Would you say it is a "DIY" job?

What did you say to the dog? And what was their response?

Actually, we'd knocked through between two reception rooms to make a larger room (you can see where the wall used to be along the floor). The skirting was different in both rooms (torus in one side, and a fancy 9" recency style in the other). I ended up pullling it all off, and replacing it with a replica of the recency design I had matched to sample. But yes - I would have removed skirting anyway for both the DPC, and to run the karndean under the skirting for a neater finish.

Sorry for the random photo, but it ended up looking like this...

Yes - I think you could DIY it. I just wanted to hand over the DPC side of things to the Karndean fitters as it would be a route out of the warranty if they deemed the DPC to be at fault down the line.

They were ok about the dog...it was being grinded flat in the morning anyway, so they just filled the depressions with a quick setting compound first .

 

[thezappa]

Personally I would hesitate against a covering the floor with epoxy (and then latex, as above). One thing I consistently read about is the quickness of people i.e. commercial companies to diagnose rising damp and then provide a 'solution' of a covering or injection to solve it. The reality, in my mind at least, is that there should be a more effort made to address the root cause. Covering a floor with bitumen/latex or injecting a wall with silicone is not a solution, it only serves to move the moisture somewhere else.
If the floor is damp as in your case I would suggest investigating ventilation. I suspect the damp proof membrane you can see has caused the moisture to be pushed to the sides of the room - hence the moist under the skirting, putting an impermeable liquid down over the top of the floor will only serve to reduce the escape route for the moisture trapping it along the edges and [potentially] causing more decay.
Perhaps a better solution would be the ventilation option, most likely sub-floor (since the moisture has to come from somewhere), but's just me. My gf doesn't even agree with my opinions on damp/moisture diagnosis and treatment.

 

[Gimpymoo]

You make a valid point and are correct in the points you raise and it is something I am also investigating.

We have no airbricks in the property. Well, I found one which was rendered over on the outside and is now buried behind skirting.

We take these old houses, make them airtight with double glazing but few think about ventilation.

You say "sub floor". With only having a concrete floor, you mean rip up existing concrete floor and install a raised wooden floor with venting underneath?

In all fairness, a concrete floor with functioning damp course is just as valid.

I do need to investigate ventilation though.

 

[Skiddley]

For what it's worth, we had the same reservations, but we've seen no evidence of rising damp at the walls since.

I'm sure local conditions may play a part in how likely that is. Just wanted to give the OP another avenue to explore.

 

[thezappa]

You make a valid point and are correct in the points you raise and it is something I am also investigating.

We have no airbricks in the property. Well, I found one which was rendered over on the outside and is now buried behind skirting.

We take these old houses, make them airtight with double glazing but few think about ventilation.

You say "sub floor". With only having a concrete floor, you mean rip up existing concrete floor and install a raised wooden floor with venting underneath?

In all fairness, a concrete floor with functioning damp course is just as valid.

I do need to investigate ventilation though.

It could be you have a suspended concrete floor, probably added after the house was built (almost certainly) so it will be suspended, also the floor wouldn't have been built directly on to a concrete slab.
I wouldn't rip up the floor but certainly look at the ventilation, to save the money if nothing else The floor you have will be fine as long as the air can pass and move freely. They should be spaced about every 1500mm (in modern houses), if you have one look on the opposite elevation. Just because it is concrete doesn't mean it doesn't need air passing over it.
Moisture in concrete is bad, it just takes longer to cause a major problem than it does in wood.

Problem is you can't just lift a floor board and have a look, you could if you're confident (and have the tools) cut out a couple of bricks at ground level and look at what is underneath the floor, might even find you have a blocked cavity as well which won't help.

I completely understand why people go down the 'tanking' route though, its a hell of a lot cheaper and quicker but my reservation is that it doesn't solve the problem

 

[fixerupper]

Hi, new to this forum with the same issue/queries as @Gimpymoo. Like Gimpy, I live in Nottingham and my house is the same age. After 6 years of trying to get a diagnosis for the damp on my internal walls as well as external, despite 2 x damp proof courses, I've reason to conclude the issue is water (literally) coming up through the concrete floor (front and back).

Mine is going to be difficult to access as my back room and hallway are (continuous) herringbone parquet. Another complication is that I teach from home, and my (carpeted) front room needs to be available/presentable throughout the school year.

Having invested £25k in my stupid house's issues, I'm starting to wonder if this is where I draw the line and seek a healthier house. I don't have anywhere I could stay while this work is completed, and every day of cancelled lessons is professionally risky as well as expensive. @Gimpymoo, what did you end up doing and what did it involve in terms of time/cost/disruption? I'm hoping you're still on here - I know it's an old thread.