Condensation and Damp - Another tale of woe!

TranquilityBase93

Hello!
So it seems like quite a familiar story...
We are tennants of a ground floor two bedroom flat and we had severe damp and condensation problems last winter, specifically in the master bedroom. It has a large bay window, and the wall underneath was constantly damp to touch and obviously started growing black mould, whilst the windows were soaking wet every morning. The room was noticeably damp elsewhere too, and often our duvet and clothes were damp to the touch. We went through the prescribed routine of making sure the flat was well heated, well ventilated I.e we made sure we opened the windows during the day etc. This had minimal effect but the landlord said just keep trying. We did, but eventually winter was over and the problems abated.

A couple of weeks ago, the condensation and mould issues returned (following some rain) and it's back with a vengeance. Again, we've tried all the usual solutions and I bought a humidity sensor. As I write this, it's clocking the humidity of the master bedroom at 94%, which surely is ridiculously high? The room temp is 18c and we don't do anything abnormal moisture wise, and the presence of the mould is starting to cause damage to valuables.

The landlord is adamant it isn't structure related and must be something we are doing. Surely he is incorrect? He's offered to buy us a dehumidifier (but emphasised it was our responsibility to do so, but he was doing us a favour) which, if it stops the humidity/mold/condensation, then great. But will it?  Any ideas of solutions or counter arguments I can provide to the landlord when dealing with this situation?

Thank you!

RelievedSheff

The dehumidifier won't stop the cause of the condensation but it will reduce the damage it is causing and bring the humidity down.

94% humidity is stupidly high for any room.

Ventilation is the key to combating condensation but if the room is as damp as you say then the dehumidifier will certainly help massively.

You do need to find the source of the problem though as it won't fix!

FreeBear

RelievedSheff said: 94% humidity is stupidly high for any room.

Agreed. Looking at the data from humidity/temperature sensors here, over the last three months, humidity in the bedrooms has been in the 50-60% range. Even in the kitchen, humidity has peaked at 74% for a single day.

For a room to be that damp, there must be water penetrating from somewhere - The first place to start looking is the ground levels outside the bay window area. See if you can identify where the damp proof course is, and measure soil level in relation to the DPC.

Or post some images here, and we can comment - One reasonable sized image showing the bay and adjacent ground level. One of the roof structure over the bay, and any gutter/downpipes.

Homer_home

Clearly water is getting in as it's happening after it rains.

What type of floor do you have ? Is it suspended or concrete?

What is the state of the brickwork under the window , any missing mortar/cracks in bricks?

What is outside the window  and does it breach the dpc? 

You might benefit from getting a professional survey done , that should stop the landlord trying to fob you off, has he even had anyone round to have a look?

TranquilityBase93

FreeBear said:

RelievedSheff said: 94% humidity is stupidly high for any room.

Agreed. Looking at the data from humidity/temperature sensors here, over the last three months, humidity in the bedrooms has been in the 50-60% range. Even in the kitchen, humidity has peaked at 74% for a single day.

For a room to be that damp, there must be water penetrating from somewhere - The first place to start looking is the ground levels outside the bay window area. See if you can identify where the damp proof course is, and measure soil level in relation to the DPC.

Or post some images here, and we can comment - One reasonable sized image showing the bay and adjacent ground level. One of the roof structure over the bay, and any gutter/downpipes.

Thanks for your replies all. I'll get back with answers this evening. The landlord bought a dehumidifier this morning so hopefully that can help, at least whilst we are tennants anyway. But even after that, I'd still like to get to the bottom of the actual issue as it's a nice flat and it would be a shame if it was severely damaged.

Teapot55

You probably do know this, but I’ll say it anyway: if you’re using a dehumidifier you have to keep the windows closed, otherwise the dehumidifier will be trying to dehumidify the air coming in the window as well. 

We bought a dehumidifier recently & it takes pints of water out of the air! It says that it’s designed for up to a five-bedroomed house but sometimes we use it in a closed room as well, like when we had wet coats to dry off & the weather was too warm to have the heating on (no tumble drier). 

TranquilityBase93

FreeBear said:

RelievedSheff said: 94% humidity is stupidly high for any room.

Agreed. Looking at the data from humidity/temperature sensors here, over the last three months, humidity in the bedrooms has been in the 50-60% range. Even in the kitchen, humidity has peaked at 74% for a single day.

For a room to be that damp, there must be water penetrating from somewhere - The first place to start looking is the ground levels outside the bay window area. See if you can identify where the damp proof course is, and measure soil level in relation to the DPC.

Or post some images here, and we can comment - One reasonable sized image showing the bay and adjacent ground level. One of the roof structure over the bay, and any gutter/downpipes.

I took these pictures today, let me know if you need any more.

Homer_home said:

Clearly water is getting in as it's happening after it rains.

What type of floor do you have ? Is it suspended or concrete?

What is the state of the brickwork under the window , any missing mortar/cracks in bricks?

What is outside the window  and does it breach the dpc? 

You might benefit from getting a professional survey done , that should stop the landlord trying to fob you off, has he even had anyone round to have a look?

He said it was surveyed and everything was fine just before we moved in (September 2019), but it's becoming obvious that that isn't the case. And I am very much considering getting my own done, again as you say just to drive it home to the landlord that this is an issue he needs to sort. 

With the dehumidifier, I've had it on most of the day and it's got the humidity down to around 60% but it seems to have plateaued now (I've got thedehumidifier humidisat set to 40%). I'll see what it comes up with tonight and over night.

TranquilityBase93

And just to add, most of the mould issues are directly on the other side of those walls underneath the bay window.

JohnB47

I wonder where the damp proof course is? In my house, 1930's built, the course runs along the top of the vent grills. Any chance of good pictures of whats above that bay window? Are you new tenents - ie nobody stayed there before you? If not, is there any way of contacting previous tenents and asking if they had damp problems? Are there open vent grills at the back of your flat - ie is there a good path for air to circulate under the flooring?

Jeepers_Creepers

As Mickey says, this could still be condensation rather than penetrating. It does seem strange it's happening so early in the year, tho', while the weather is still very mild. Having said that, the ambient humidity levels during the day have been very high recently, so perhaps that's contributing to it.

Tranquility, you said "I.e we made sure we opened the windows during the day etc." That'll help, but if you close the windows as soon as you get home, the warm air inside the house will continue to build up moisture content (from bodies, cooking, baths, showers, drying clothes, etc) and, being warm, this air will hold more moisture than the fresh air did during the day. By the end of the evening, your internal air will be pretty much saturated.

Then off to bed, CH turned down or off, air temp drops and can no longer hold this moisture - this will find the coldest surfaces to condense out on.  The result is that you wake up to running windows and damp external walls, usually in the bedroom as your body(ies) continue to give out copious amounts of moisture during the night.

Solution? Either a hot or chilly one. Hot - keep the CH turned up high overnight so that the air can continue to hold the huge amount of water being emitted. That will, of course, be deeply unpleasant for most folk and will cost a small fortune. (I remember as a student many many decades ago staying over at an Iranian student-friend's flat - he kept the gas fire burning high all night as that is the temp he was used to. On the floor in the same room, I had a deeply miserable time, sweating like a pig and with a permanently dry mouth.) The other solution is the chilly (and sensible) one - just before you jump into bed, make sure the heating is low or off and crack open the bedroom window(s). Snuggle under the duvet and wake up to a coldish - but dry - room. (Have the heating timer set to come on before you get up, and kick your partner out of bed and demand (a) a cuppa, and (b) they shut the windows.)

Looking at the level of that vent on the outside, do I take it that the internal window cill is only around a foot or so above floor level? 

Is that black stuff on the bricks mould? If so, wow, they must be pretty saturated. How thick is the wall - around 9"? If so, likely it's solid brick so no cavity. This will make it poorly insulated and also more easily allow driving damp to come through if the mortar is failing. However, there are only three rows of bricks above the vent, so not really a lot of wall to let damp through.   

Are you willing to try the 'chilly' solution for a few days? :-)

TranquilityBase93

Jeepers_Creepers said:

As Mickey says, this could still be condensation rather than penetrating. It does seem strange it's happening so early in the year, tho', while the weather is still very mild. Having said that, the ambient humidity levels during the day have been very high recently, so perhaps that's contributing to it.

Tranquility, you said "I.e we made sure we opened the windows during the day etc." That'll help, but if you close the windows as soon as you get home, the warm air inside the house will continue to build up moisture content (from bodies, cooking, baths, showers, drying clothes, etc) and, being warm, this air will hold more moisture than the fresh air did during the day. By the end of the evening, your internal air will be pretty much saturated.

Then off to bed, CH turned down or off, air temp drops and can no longer hold this moisture - this will find the coldest surfaces to condense out on.  The result is that you wake up to running windows and damp external walls, usually in the bedroom as your body(ies) continue to give out copious amounts of moisture during the night.

Solution? Either a hot or chilly one. Hot - keep the CH turned up high overnight so that the air can continue to hold the huge amount of water being emitted. That will, of course, be deeply unpleasant for most folk and will cost a small fortune. (I remember as a student many many decades ago staying over at an Iranian student-friend's flat - he kept the gas fire burning high all night as that is the temp he was used to. On the floor in the same room, I had a deeply miserable time, sweating like a pig and with a permanently dry mouth.) The other solution is the chilly (and sensible) one - just before you jump into bed, make sure the heating is low or off and crack open the bedroom window(s). Snuggle under the duvet and wake up to a coldish - but dry - room. (Have the heating timer set to come on before you get up, and kick your partner out of bed and demand (a) a cuppa, and (b) they shut the windows.)

Looking at the level of that vent on the outside, do I take it that the internal window cill is only around a foot or so above floor level? 

Is that black stuff on the bricks mould? If so, wow, they must be pretty saturated. How thick is the wall - around 9"? If so, likely it's solid brick so no cavity. This will make it poorly insulated and also more easily allow driving damp to come through if the mortar is failing. However, there are only three rows of bricks above the vent, so not really a lot of wall to let damp through.   

Are you willing to try the 'chilly' solution for a few days? :-)

So this is other side of the bay window (featuring mould and dehumidifier(s). So I'd say probably maybe 2 and bit feet from the ground to internal sill. And I'd be happy to leave the window open, if that helps the issue. The bedroom fronts onto a decently busy A road but we should be able to manage with the noise.

JohnB47 said:

I wonder where the damp proof course is? In my house, 1930's built, the course runs along the top of the vent grills. Any chance of good pictures of whats above that bay window? Are you new tenents - ie nobody stayed there before you? If not, is there any way of contacting previous tenents and asking if they had damp problems? Are there open vent grills at the back of your flat - ie is there a good path for air to circulate under the flooring?

On the outside? It's a slated roof, but I can provide a proper picture of that in the morning. On that subject, we've noticed that a few of the slates have come loose and that may potentially be the source of water? In terms of the previous tenants, I have not been in contact with them but I've been told that this is a new issue, potentially because it's the first time this property has been let to a couple rather than a single occupant. So maybe the extra body in the room has exacerbated things.