Damp advice please

[Bilbous]

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• Bilbous
• 8 Dec 2014
• 1

As you can tell from the title and the image I have a bit of a moisture problem in the front room.
Problem was first noticed in May this year (it could have been a problem for a lot longer but the previous owner did a good job of hiding a lot of things)

Floor and skirts are dry to the touch and there is no condensation problems on the windows or door.
Chimney pot serves both our house and next door and each side has 4 pots. We got the stack checked and the roofer replaced some mortar and sorted out some flashing that had come loose.
The pots do not have cowls (This is our next step).
The fireplace has a bog standard focal electric fire which is never used.
The room is also rarely used.
I ran a dehumidifier in there for a couple of weeks and it was pulling a lot of water out every 24hours. and the area was drying but as soon as it was left off for 24 hours it was wet to the touch again.

The external wall is in a shared alleyway between the 2 houses so it is not subjected to the weather. There is also a row of injections below the original DPC and another row 2 bricks above the original dpc.


The damp are has grown a little bit but since we first noticed it in May but only about an inch in height.


Any insight would be helpful and appreciated.

 

[ree]

The gripper is the wrong way round (lettering towards you) - lift it all around the c/breast, and roll back the coverings to expose the wood floor and/or hearth.

Has the flue (all your flues) been swept?

That is not condensation (although it may begin to attract condensation) but penetrating damp. Do you have a rad in the room? Carefully examine the whole of the external walls from floor to ceiling - look for slight staining and feel with the back of your hand for damp.

Why not post pics of the exposed floor, and the front of the c/breast, and the external chimney back wall near DPC ground level, and up the pointing to guttering or verge height?

Note: best practice in modern roofing work is to present the client with before and after pics.

 

[Bilbous]

Will pull carpet etc back tomorrow etc and take a bunch more pics.
not been swept no.

 

[Flyboytim]

It could well be cold bridging from the electric socket box and a conduit down to the subfloor space, with the subsequent draught continually chilling the box during the spring and autumn/winter months. In the summer, despite humid and warm conditions, the cold spot remains, but without the temperature difference to elicit overt dampness.

Evidence? Apart from the nearly circular border of damp around the socket - the room is rarely used, and the decorative electric fire also. Presumably the room is kept cooler than a regularly occupied room in the same house, during colder weather - if there is a radiator, is it beneath the window, and the door opens to the outside? The room is usually open to the rest of the house?

Air that is not moving around the room tends to stagnate in corners and cold bridges will cause condensation that will soak through the gypsum plaster skim enlarging the cold spot and the continued condensation.

The dehumidifier shows that the air is damp. It is an expensive way to dry the air, and will do little to lessen the focal damp spot.

You need air movement to even the temperature of the wall with the surrounding air. An ordinary desk fan on low speed pointed towards the damp will evaporate the moisture and eventually equilibrate the temperature of the wall around the socket.

Like driving a wet car around after the rain, the raindrops soon evaporate despite little outside humidity or temperature change - air movement is very effective on damp porous surfaces.

 

[Bilbous]

Radiator is on the opposite wall the the chimney but not a window wall (Bay window) The door in the room is generally kept closed and opens into the hallway.
There is also a band of damp on the other side of the chimney breast but this is a straight line and is about 4" high.
I will roll carpet back tomorrow and get some pictures as well as lifting a couple of boards so i can get some pictures of the sub floor area as well.
Thanks for the replies so far.

 

[Bilbous]

Ok today the wall feels dryer to the touch.

Picture of right side of chimney breast (closest to middle of house)

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• Bilbous
• 9 Dec 2014
• 1

Left side of Chimney breast, floors dry and you can see where the wall has had the damp although this is now dry to the touch. (Bay window starts on the wall to the left)

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• Bilbous
• 9 Dec 2014
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Floorboard up on right side with view down, also some other views of the sub floor area.

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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
• 1

Chimney pics, the other 3 rooms in the house that are served by this stack also show now signs of damp or any problems. (1 downstairs and 2 upstairs)

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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
• 1

Smoke test on chimney and it pulls the smoke away nicely so seems fine....
Cannot see any actual vents on the electric fire and that was sealed into place, the dust etc behind it was all bone dry.

 

[ree]

Thanks for the pics they are really helpful.

Further pics showing the ground level in the alleyway (i guess its a tunnel?) at DPC height would also help. So would pics of the front (bay) elevation showing the ground level/DPC, and any air bricks. I'm looking for thro ventilation & damp bridging.

You seem to be in a pretty good state given that there is excessive moisture in the lower brickwork on the c/breast wall, and the sub-area soil is very damp (the water in the dehumidifier is coming up from the sub-area).

All wood debris on the oversite should be removed - it attracts fungii.

The junction box lying on the soil should be pinned to a joist and the wrapped cable needs a junction box. The cable and flex for the elec. fire need sorting out - best practice is always to run cable etc. below the floor.

The chimney stack pics show a partial sand and cement fillet instead of lead cover flashing - perhaps check in the loft for any leaks.

 

[Bilbous]

I will take pics of areas suggested later. The flex cables you see are actually HDMI cables and I will get the electrics sorted out (first time i have seen them this week) below the floor.

Now my friend who is a plumber suggested the problem could well be a leak on the mains water which runs underground in the alleyway and the neighbour has at least a problem on one side of her chimney breast. I have contacted the local water authority who said they would come and check water supply so at least it will help eliminate one possible source.

 

[ree]

Perhaps pic the neighbour's side of the alleyway and ask if you can view and pic the interior damp by her c/breast?

We could show you how to check your water mains for leakage but, for now, let the utility do it.

My queries might seem extensive but, back in the day, all this, and more, would be covered in a few minutes on site. Neighbour's can be a goldmine of information.

 

[Bilbous]

Right done some more digging and exploring and regarding the air circulation. I noticed there is no draught under the floor and with it been very windy outside i found that strange. Did a smoke match in the sub floor and the smoke just drifted up and nowhere else so i need to explore the air bricks at the back of the house tomorrow daytime. There are french upvc doors at the back and it has a brick step with slabs. I have a feeling that step is covering the airbricks there.

Alley between houses

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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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Bay window (there are 3 airbricks under the bay window and another 1 either side so a total of 5)

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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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• Bilbous
• 9 Dec 2014
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[ree]

Thanks for the extra pics. Perhaps, post a pic of the rear at the steps?

You only appear to have only two 9" x 3" air bricks at the front - both appear to be blocked. You would do better to install 9" x 3" plastic air bricks - replacing the in place air bricks - or clean them out.

The concreting around the property has raised the ground level to the original DPC mortar bed line, probably bridging the still sound DPC. The bricks look soaked and perished. The ludicrous lines of injection holes are irrelevant. Do you have solid walls?

You have enough room to crawl your sub-area and inspect the joist tails (front elev. and rear elev. & possibly round the hearth) where they sit in the brick pockets - probe them with a screwdriver. Check that there is honeycombing and a thro draft. in the dividing wall to the left of the c/breast.

 

[Bilbous]

There are 3 in the bay itself and another 2 (1 either side of the bay)
I will take up a couple more boards tomorrow and see if i can crawl under to the front(will clear out the crap at the same time) and see if i can see/clean the airbricks.
Wall i am sure is cavity (just going by the brick formation)

I agree the concrete is too high and that will be rectified next year, however if it needs doing quicker it can be. pretty much the same around the back as well.


At the moment there is no through draft at all (And we have pretty strong winds today) but i will check there is honeycombing and i will check the joist tails.

Really appreciate the feedback.

 

[stuart45]

.
Wall i am sure is cavity (just going by the brick formation)

There are some header courses which suggest it could be a solid wall.

 

[Bilbous]

Ok here is what i could get today

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• Bilbous
• 10 Dec 2014
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Sitting room wall, which sports a couple of piles of rubble that i will remove.

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• Bilbous
• 10 Dec 2014
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Same wall further along.

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• Bilbous
• 10 Dec 2014
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This is towards the bay window and the wall running roughly in line with the chimney breast nearest the bay window.

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• Bilbous
• 10 Dec 2014
• 1

Same wall but closer to the chimney breast.

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• Bilbous
• 10 Dec 2014
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Same wall again but hallway end.

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• Bilbous
• 10 Dec 2014
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This is the alley wall with the poor cabling (getting sorted tomorrow)

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• Bilbous
• 10 Dec 2014
• 1

Sitting Room wall starting from the alley wall (Near the dodgy cable)

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• Bilbous
• 10 Dec 2014
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Sitting room wall (Leads to french doors)

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• Bilbous
• 10 Dec 2014
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Hallway wall/

There is no breeze under the floor at all, didn't get to the bay area as i was pushed for time today but i will crawl right through and inspect closer tomorrow.

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• Bilbous
• 10 Dec 2014
• 1

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• Bilbous
• 10 Dec 2014
• 1

French door airbricks were truly blocked, i have removed a couple of slabs and given a quick clean but still no airflow in the front room sub floor area.

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• Bilbous
• 10 Dec 2014
• 1

Rough floorplan so you have an idea of house layout.

 

[Bilbous]

.
Wall i am sure is cavity (just going by the brick formation)

There are some header courses which suggest it could be a solid wall.

Reliably informed it is a solid wall (My presumption was wrong )