damp stained lounge carpet - concrete floor

ThisIsWeird

homerhotspur said:

ThisIsWeird said:

homerhotspur said:

ThisIsWeird said:

homerhotspur said:

whaThisIsWeird said:

Are you sure it's a solid concrete floor, or could it be a suspended concrete type? The latter certainly shouldn't have DPM issues as it won't have one. As I understand.

Looking more like a leaking CH. Does your boiler have a whatsit?

what is a whatsit?

My apologies, hh. I'd asked previously if your boiler had a gauge, and I was reminding you of this in my incredibly funny manner

Others have explained the reasoning. Your system sounds a bit different. It would appear to be a pressurised hot cylinder, but not obviously a pressurised boiler/central heating system, as the boiler itself doesn't appear to have a pressure gauge. However, there then appears to be multiple pressure vessels fitted. 

We need to get to basics. 

1) Make and model of the boiler? A photo would be useful too. 

2) Does your downstairs have wall-mounted radiators, or underfloor heating?

3) have you had to 'top up' anything in your boiler/ch system this year?

1) Baxi eco blue advance
2) Wall mounted radiators
3) No

I was shown how to top up the pressure when the boiler and cylinders were fitted, so that is definitely a thing with this set up.

Thanks.

Based on no top-up required, I'm going to speculate that your CH system isn't leaking. 

That leaves, I think, two options; you have 'rising' damp - I suspect very unlikely, as the water table is surely low, and DPMs just don't fail in no good reason, and not in multiple places at once - and a leaking pipe that is letting water land on top of the floor, and is then travelling under the vinyl tiles, popping up wherever there's a joint gap. That can easily disguise the actual source of the water.

Pure speculation, of course, but I think the obvious move is to full remove your carpet, and lift the tiles below. Then you can stand back and look at what happens, and where.

thank you very much. What sort of pipe would this likely be, a mains water pipe?

What I'm saying is pure guesswork. Since your CH system is seemingly a 'sealed', pressurised type, and since it doesn't appear to be losing water, then I'm suggesting that a leaking CH system is unlikely.

Since the patches are numerous and appearing during what I presume is a period of very dry weather, then I'm suggesting that 'rising' damp through a breach of the DPM is unlikely. Also, such a breach would tend to be shown in the area where it occurs, as a vague damp patch and not a 'wet' one in numerous places.

So, I'm guessing the water is coming from a source that's above the floor, so - yes - this would be from a pipe in your home, but above ground. Could be mains, could be hot or could be cold.

Such a leak could end up pretty much anywhere once it hits a solid floor like yours, and cannot go anywhere else. Again pure speculation, but there must be a chance the water is travelling under the vinyl tiles, is beginning in one spot in that room, and possibly originating from an adjacent room.

So, I'd be lifting these tiles in order to try and identify which of these damp patches are genuine sources, and looking suspiciously at any above-ground plumbing in adjacent rooms. Where's the kitchen in relation to the room? Bathroom? The hot cylinder cupboard? Check the floors of these rooms very carefully, especially along the floor edge that meets the 'damp' room.

markin

plumb1_2 said:

Barrett’s houses won’t have heating pipes in the concrete floor, they are behind the plasterboard walls. 10mm in plastic truncking. Fitted loads , If rads are in bay windows the pipes will be behind the skirting, after dropping down from above. 

looks like the dog 😊

Copper
, pvc  or pex in 1996

badger09

homerhotspur said:

badger09 said:

I hope for OP’s sake he doesn’t have underfloor CH leaks

We have a 1970s built, 1990s extended bungalow with concrete floors. We noticed rapid boiler pressure loss which several applications of sealant failed to fix. Specialist track & tracer company were unable to find the leaks, despite digging up some of our tiled floor. 

We definitely notice much greater pressure loss when CH is on for longer periods during autumn & winter. We’ve decided that even if one or more leaks could be traced, the chances of more occurring is too stressful to contemplate, so we’re having all the CH pipes rerouted above ground. Going to be expensive & disruptive, but at least we’ll be able to sleep at night & go away during the winter. Due to start work early next month. 

Thanks ( I think !)
I'm coming round to this being the most likely  cause. The thing that is confusing me is not seeing any evidence of actual moisture/ water anywhere other than soaked into the , now removed, underlay. Ive put the heating and water heater on but nothing has happened. Would this only happen when this is running? I'm now waiting for forecasted heavy downpours this afternoon, just in case it is anything to do with the water level under the floor?

We didn’t have any damp patches anywhere, just drops in boiler pressure, increasing when CH was running. 

As it seems from later posts that this isn’t your issue, I’ll butt out now rather than derail. 

Good luck

plumb1_2

markin said:

plumb1_2 said:

Barrett’s houses won’t have heating pipes in the concrete floor, they are behind the plasterboard walls. 10mm in plastic truncking. Fitted loads , If rads are in bay windows the pipes will be behind the skirting, after dropping down from above. 

looks like the dog 😊

Copper
, pvc  or pex in 1996

Copper,   Pvc mainly industrial/ commercial,  and small number in domestic properties on h&c 

homerhotspur

plumb1_2 said:

Barrett’s houses won’t have heating pipes in the concrete floor, they are behind the plasterboard walls. 10mm in plastic truncking. Fitted loads , If rads are in bay windows the pipes will be behind the skirting, after dropping down from above. 

looks like the dog 😊

Plumber has been out and all but ruled out leaking pipes as the cause. He has cast doubt on our damp proof course as a) he can't see one and b) the bottom 2 bricks look and feel damp ( I always put this down to it being very shady and North facing).
As a former Barratts contractor, do you have any idea of the sort of DPC they used in 1996 with solid concrete floors?
Many thanks

plumb1_2

As far as iam aware they used a Visqueen type membrane. 

homerhotspur

Thank you very much. I think the thing that has caused suspicion is the lack of any visible sign of one. I have just looked at other houses on the  estate and cannot see any signs either of a black sheet line or similar. Any idea if they fitted them so they weren't visible in some way?

stuart45

The external DPC in the face work is not always visible, although it won't really affect the concrete floor. It's the DPM that protects the floor from damp, although if there's been heavy rain and it's full of water, the labourers have been known to make holes in it to drain it before the concrete went in.

plumb1_2

stuart45 said:

The external DPC in the face work is not always visible, although it won't really affect the concrete floor. It's the DPM that protects the floor from damp, although if there's been heavy rain and it's full of water, the labourers have been known to make holes in it to drain it before the concrete went in.

Indeed not many site labourers walk around with a mop and bucket, when a spade will do the job.