Condensation and mold woes

[ShaunB]

Hi all,

Long time reader, first time poster. Hopefully someone out there can help, i'm struggling with this one!

Long story short, the ceiling in our porch (i say porch but its really a small hallway that pertrudes the front of the house with a flat roof) gets condensation on it from time to time and this results in mold forming.
We had a new front door fitted along with windows around a year ago but no change, i have turned the radiator completely off, on slightly and fully on and either way the condensation appears. We even went to the trouble of coating the flat roof outside with bitumin, in case water was getting in somwhere but this didnt solve it.

I'm stumped, i know its going to be somthing to do with the ceiling being cooler than the air but this cant have been doing this since the house was built, around 1965, ex local authority. A neighbour had this and resorted to having a pitched roof put on, but next doot has no trouble what so ever.
In the pictures you can see where i have removed the paint back to plaster, treated with mold killer, painted with damp seal and then one coat of white paint before i noticed the condensation was still appearing.
Father in law suggested Round drill weep vents, however i dont have experience of these so would that help?

Any help much appreciated,
Shaun

 

[Burnerman]

I think we need a picture of the flat roof from outside.....I reckon that's more than condensation.
John

 

[ShaunB]

Hi John,

Thanks, i've got two pictures here that i took a while ago from ground level, i'll take more tomorrow morning showing the roof and stick them on.


Shaun

 

[ShaunB]

Here's a picture of the roof from above.

Cheers,
Shaun

 

[Chud]

I don't see any guttering or drip bars/channel - can you take a picture outside looking up at the edge of the roof?

 

[ShaunB]

Hi,

Sorry for the late reply, here's some pictures from the underside looking up. No gutter, just an overlap all the way round.

Shaun

 

[Burnerman]

Just my theory Shaun, but when it rains, is water coursing over the edge and onto that concrete slab roof......maybe its being kept permanently damp due to this and the thing is saturated somewhat? Naturally enough, the slab will always be cold, but see if you can spot where the rain goes.
John

 

[jeff the gasman]

Six month fix is a product called Muffycid. Just spray it on and the mould will disappear guaranteed.
When it starts to come back just re-apply. I can't believe how good this product is.
Google will find it.

 

[Chud]

Just my theory Shaun, but when it rains, is water coursing over the edge and onto that concrete slab roof......maybe its being kept permanently damp due to this and the thing is saturated somewhat? Naturally enough, the slab will always be cold, but see if you can spot where the rain goes.
John

That's kind of what I was thinking too - it doesn't look like there's much of a 'drip channel' to the underside of the roof (sorry not sure of the technical term!) so I'm wondering if water is running round to the underside and back into the house or just soaking the concrete. (see roof 1 png)

An easy way to find out would be to insert a strip of plastic etc between the edge of the roof and the concrete to act as a drip 'lip' (see roof 2).

 

[ShaunB]

Thanks to you all for the advice, will see if I can try making a drip lip and see if that helps.
The slab is, I think, a timber frame with some sort of concrete or render over it. When I was round one of the neighbours I could see timber where concrete had broken off, so I can see that getting saturated could be making the inside of the roof wet and maybe leeching through the ceiling.

Cheers again everyone, I'll report back once I've got an update.
Shaun

 

[ntb]

I have an alternate possibility. Was the porch originally open? i.e. the door was further back and has been moved forward to its current position? If so, it is condensation from the warm air of the house hitting the cold roof. In this case, you will either have to insulate and vapour seal the ceiling or move the door back to its original position.

 

[cjard]

Or remove that top pane of glass over the door to permanently ventilate the porch, and better seal the house so that warm moist air from it cannot reach the porch. Also, are you certain that water cannot get under the edge of your nice new roof where it joins the neighbouring house? I notice that he hasn't had his roof done..

 

[Doggit]

I think ntb's on the right course. Assuming the porch is outside the main front door, then moisture in the porch is hitting the ceiling and then condensing. Part of the problem will be lack of ventilation in the porch, and lack of insulation in the roof. Does the hallway merge in to the porch area, or is there an inner front door. Is the porch a single skin wall, and is there a DPC in it. How does the construction of the complete porch (rather than just the roof itself) compare to the other properties.

 

[ShaunB]

Firstly apologies for not getting my backside on here sooner, been so busy these last few weeks. We seem to have cracked it and, fingers crossed, no longer have condensation forming.
After speaking to our neighbour and inspecting their setup they have air bricks on either side of the porch/hallway which go through to the inside with vents that can be closed off. After some drilling in our hall we discovered the original holes where vents would have been, just filled in and plastered over. Removal of this revealed a lined cavity through to the outside air bricks we have, and so we have reinstated these.

I will still reply to the unanswered posts though.

I have an alternate possibility. Was the porch originally open? i.e. the door was further back and has been moved forward to its current position? If so, it is condensation from the warm air of the house hitting the cold roof. In this case, you will either have to insulate and vapour seal the ceiling or move the door back to its original position.

The "porch" as i describe it is integral to the house, in that if you were to remove it, the front room door and bottom of the stairs would be on show to the neighbours.
Its a strange construction in that its a small hallway but sticks out from the house rather than being within the line of the front of the house. The front door is where it has always been, not been moved forward (this was done at my parents to make a larger hallway, but their porch went into the house rather than sticking out)

Or remove that top pane of glass over the door to permanently ventilate the porch, and better seal the house so that warm moist air from it cannot reach the porch. Also, are you certain that water cannot get under the edge of your nice new roof where it joins the neighbouring house? I notice that he hasn't had his roof done..

We had checked both roof's and the join between ours and next door is good.

I think ntb's on the right course. Assuming the porch is outside the main front door, then moisture in the porch is hitting the ceiling and then condensing. Part of the problem will be lack of ventilation in the porch, and lack of insulation in the roof. Does the hallway merge in to the porch area, or is there an inner front door. Is the porch a single skin wall, and is there a DPC in it. How does the construction of the complete porch (rather than just the roof itself) compare to the other properties.

See attached pictures to show the inside layout, our house is the same construction as a lot of our neighbours. I probably didn't explain the construction of the hall/porch very well and should have used the term porch very loosely!

View from front room:

View from stairs:

Vents:

Thanks to everyone for all the help and advice, i shall be keeping a close eye on things and hopefully the condensation, and more importantly the mold, wont return!