Brick wall and damp

[Molebob]

I have just purchased a house and there appears to be mold (which was well hidden on viewings) in a couple of places which both seem to be caused by walls in the garden. In one case the shared wall with the other semi has a small gap of a couple centimeters between it and the house. A small amount of rubbish and snails have got in there but you can see the white painted render has a greenness to it, the same colour as the mould inside. The other wall on the other side of the house is attached and there is some evidence of mould in a kitchen cupboard on the inside of the wall - I haven't investigated further.

I am not sure what options I have beyond just knocking the walls down?

 

[dann09]

Can you post pics internal and external, of the areas in question?

 

[Molebob]

I have uploaded the photos here: //www.diynot.com/network/Molebob/albums/15458

I haven't looked further behind the kitchen cupboard to see what is going on yet. As a new boiler is going in next week that area will be opened up.

 

[dann09]

Thanks for the pics:

1. First, clear the gap between the wall and the house of all debris - does your neighbour complain of any similar interior difficulties?

2. Pic 4 shows condensation. Is pic 4 the inside corner of pic 7?

3. Pic 8. Remove the cupboard from the wall now, if possible, and inspect and pic behind it.

4. Condensation might be being assisted by the large, cool glazing of the sliders. Do you have an extractor in the area, and radiators?

5. Clear the RWP gulley in pic 7.

6. The black render plinth appears to be bridging the DPC, and in contact with the ground.

7. Is this a cavity wall ( any cav. insulation?).
Is the floor solid or suspended?

 

[Molebob]

Thanks for he detailed reply.

I plan to ask her if she has noticed anything but only purchased the house last week and haven't moved in yet.

Pic 4 (the one with the hideous striped wall paper) is the other side of pics 1-3 (the wall not quite touching) - the corner being just by the patio doors.

I will try and remove the cupboard later this week, I fear what I might find!

There is an extractor fan in the kitchen for pic 8, no radiator but there is what appears to be a heater under the oven. Pic 4 has a large radiator in it.

I was aware from the survey that the DPC was being breached but nowhere else in the house has any signs of damp or mould beyond this two points. I plan to fix it at some point but didn't think it was a major priority? Most houses on the street are the same.

Our surveyor didn't think it was cavity wall, I haven't had a chance to look (built around 1927 in south london). The floors are just floorboards above a reasonable sized void, so I assume that is suspended.

 

[Molebob]

I asked my neighbour whilst I was there today and she hadn't noticed any issues but then she may have furniture or something in the way.

 

[Molebob]

I have just pulled on the laminate floor and looked in to the void to see where the damp proof course is. I notice the step down from the patio shown below breaches it. Is there any other solution beyond removing it? Also the plaster around the wall that doesn't quite touch is a little hollow sounding. We had a full buildings survey and he failed to notice any mould, any plaster issues or mention the step!

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[dann09]

Thanks for coming back:

1. Has the wall gap debris been cleared?
Has the cupboard been removed?
Is it a cavity wall or not?

2. Why are you pulling up your flooring? Surely, there is an access trap to the sub-area? Typically, below the stairs.
Go crawl your house, and determine the state of the joist seats in the sliding door area.

3. Where are your sub-floor air brick vents?

4. Hollow "plaster around the wall" - what wall?

5. The step will have to be removed, and re-built, and the render cut back above DPC level. There's the possibility of cutting a channel, but thats an on-site decision.

Note: that your neighbour doesn't have a flashed drip cap above the sliding doors - perhaps you dont. One should be fitted.

 

[Molebob]

1. Not yet for either clearing or cupboard inspection. It is not a cavity wall.

2. The laminate floor had to be up for the electricians to rewire, so I had a look under the floor to see if I could spot anything. It isn't the largest sub floor area to crawl under but probably doable.

3. There is one under the patio door, two on the side and one in the front of the house. There is also one at the front that is now in the porch addition.

4. I meant the render low down between the sliding door and the wall with the debris sounds hollow when tapped.

5. I had a feeling that would need to happen.

So the points so far are to clean that wall out, move the step and look behind the cupboard to see what is going on. The front rooms of the house and the upstairs have no mould issues just the back wall low down, also it does not feel damp. The surveyor said he tested multiple walls (during October) and no damp readings.

From a photo I can see there is some sort of drip cap.

 

[dann09]

I suspect that you have condensation issues due to cold spots on the solid walls.
There is also the possibility that the render has retained water here and there, including at the rear wall area.
Any "hollow" areas - "knock off" until firm render is reached.

Research on here about renders, and patching, and masonry painting them.

You need more vents esp. at corners for cross ventilation.

 

[Molebob]

Thanks for the advice, I will investigate and research further.

 

[Molebob]

So after some further investigation today it turns out that there is a lead water pipe and it is leaking. So that may explain some of the mould in that room and I have noticed by the radiator there is mould stains, so I guess the previous owners liked to dry clothes on them.

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