Damp and venting

[cappsie]

Hi,

If a professional has already treated my walls for damp, but the flat is still damp, what is the advice on drilling out a core or two and putting vents in?

My plan is to put one vent in the bedroom, two in the lounge, one or two in the kitchen, one in the utility room and another in the the bathroom. I believe these are better placed higher rather than lower, but I would appreciate all advice.

Thanks,
Adam.

 

[cappsie]

*bump*

Anyone?

 

[Alastairreid]

Where is the damp coming from?

 

[cappsie]

Humidity and moisture in the air. This is why I need to add vents. I will also be investing in a dehumidifier soon.

So what do you think?

Thanks,
Adam.

 

[Alastairreid]

You need to address the cause of the moisture ie appropriate sized extractor in bathroom, cooker hood extracting externally, tumble drier extracting externally, drying washing over radiators etc.

Do you have trickle vents in windows?

Where is the moisture condensing? do you need to up the insulation on cold external walls?

There is an endless list of probabilities...more info.

 

[cappsie]

Hi,

The cause of the moisture is simply living there. There is no venting whatsoever in the flat. I have re-jigged the bathroom window so it is left slightly ajar; there is also a small vent in the bathroom as well as an extractor fan. This still does not help. My thinking is I need venting throughout the flat to allow a good airflow.

The windows are the brown wooden framed double glazing and therefore not vented. The moisture condenses on the internal walls. The external walls as far as I can tell are rendered so I cannot really tell whether there is an issue there or not.

My intention is to core-drill a few places throughout the flat, put in the vents and increase the airflow. This should help dry out the flat by allowing air circulation.

My question is: should the vents be high or low in the walls and if high, I think I'm likely to encounter RJS issues above windows unless the vent is above that - but again, how to determine this...

Thoughts?

Thanks
Adam

 

[dann09]

As Aleister said: "more info".
Before doing anything else, perhaps you should first research on here the variable issues connected with condensation and possible penetrating damp.

Dont drill or install anything until you are pretty certain what the remedy (s) is.
Examine closely, or photo the external render.

 

[cappsie]

Can you see any issues in simply adding some wall vents?

Thanks,
Adam.

 

[dann09]

Many:
installed for what purpose?
what kind of vents?
installed where?
in what kind of wall?
is it a cavity wall with insulation?
any cables, gas or water pipes channeled in the walls?

 

[cappsie]

All fair points:

installed for what purpose? -To add ventilation - there isn't any at present
what kind of vents? - Simple ducted hole with plastic vent
installed where? - Above or to the side of windows
in what kind of wall? - I believe this to be rendered, though a couple will be plasterboard on breeze block or brick
is it a cavity wall with insulation? - A cavity wall is unlikely as this was built in 1901. Originally horse hair and lime with a slate bed.
any cables, gas or water pipes channeled in the walls? - Not where I'm considering drilling

 

[dann09]

Fair enough. You know enough to safely install vents.
Unless you have access to outside vent hood/terminal positions, you will have to use "High Rise" specialty, install from inside, vents.

What precisely did the "professional damp proofer" do to your walls, and why?

Does damp appear randomly or at particular times, weather pattern or seasons?

 

[cappsie]

Hi

The damp proofer removed the existing plaster back to the brick. I'm not sure if he treated the brickwork but he applied a dark grey-looking 'damp proof' cement-type material. Finally he rendered that.

As far as I understand, this would have cured the existing damp problem and prevented any future brick-to-plaster breach. However, this doesn't cover anything underneath the property. It is an early 1900s with a slate-bed. I was told a while ago that if the slate-bed is breached there can be lots of issues.

Interstingly, now you mention it, I have noticed a recurrence of the damp on the 'cured' wall, at least in one area. The rest tends to have black mould from surface moisture which this venting will resolve.

 

[cappsie]

So I managed to get a really good deal (50% off) on a dehumidifier as it was an ex-display model. I nearly fell over when the guy said "We'll give you 50% off".

Link to it here: http://www.diy.com/nav/fix/cooling-...dehumidifiers/Blyss-28L-Dehumidifier-11787521

The dehumidifier has done wonders but I would like to switch if off one day and allow natural venting to take over. However, for now it works well.

On payday I hope to get a core drill (bit) and install some venting around the flat.