Any damp or condensation experts out there?

['The Gaffer']

I have a flat that needs a quick look over to see whether I have a problem with damp or condensation in a bedroom. 2 companies have let me down now and I suddenly thought we have a range of skills here so can anyone help me?

[fullpint]

How bad is it Phil? We had a small patch in our living room for ages. In the end I finally got round to buying some stuff from Wicks that killer the mildew off and has also stop it coming back. You dilute it with water and just brush it on. Easy fix in the end.

[bluehornetrider]

always worth checking for any broken roof tiles or gutters, quite often a blocked gutter causing water to run down the side of the house.

[garry h]

Agree with the above also worth checking your insulation and trickle vents if you have them.Most windows are fitted with sealed units so worth checking for any damage etc to those.If its a ground floor flat check the cavities are clear and not allowing damp to bridge the gap from the outside wall to the inner wall.Alot of condensation problems are caused by not having enough air flow and poor insulation.Hope this helps.   

[paintman]

Being a decorator by trade I come across this problem all the time.

If it's mould in the corners for instance this is usually due to air circulation problems.....poor ventilation caused by still air.

If it's high up on the walls could well be leaking gutter or roof problem as suggested, or porous walls.

To cover it up you paint over it with a Damp Seal, which is a very thick paint-like liquid, usually white in colour that seals the wall which then can be painted or wallpapered over.

Long as its not rising damp due to damp-coarse problems you should be ok......hope this helps.      Tony

['The Gaffer']

Thanks for the advice guys. My tenant had mould on the back of a bedside cabinet and the lower interior wall felt a little moist yet on other occasions it feels much dryer. I have had a look under the floor and the walls don't feel particularly damp. Although it looks like the walls are coated in black bitumen which was quite often used in Victorian times to prevent damp I understand. I have also installed an underfloor fan to move air to outside as there are no airbricks under that floor. The outside interior wall does not have visible lines or discolouration.

There is no obvious exterior damp or gutter problems that I can see and the window does have open trickle vents. A  bathroom ajions the bedroom that has no window but ver good fan ventilation.

I really need someone to have a look with diagnostic equipment to see what's really going on.

[garry h]

If I lived nearer I would have a look hope you sort it out 

['Mendip Wurzel']

Phil
As most are saying this is almost definitely condensation and the answer to the problem at this time of the year is to heat and ventilate. Moisture will obviously condense out on the coldest surfaces so to some extent insulation can help the problem.
Also mold does not usually occur where there has been long standing rising or penetrating damp because the salts in the structure tend to kill off and prevent mold growth. LPG free standing room heaters are also taboo, due to the amount of moisture they create.
Kevin   

['The Gaffer']

Cheers Guys.

I am looking at ways to improve the ventilation in the room without making it colder.

[benchmark51]

I've just watched a 'Grand Designs' programme on 'More Four' channel. It was building a Cob house that had to be super insulated and part of the build regs called for a ventilation system. Basically old air drawn out via plastic pipes, fresh air pumped in via plastic pipes and both going through a heat exchanger so the incoming fresh air is warmed by the stale air going out.

['Mendip Wurzel']

Cheers Guys.

I am looking at ways to improve the ventilation in the room without making it colder.

Phil
Just looking at the windows is a good indicator.... if you have loads of condensation forming on the internals of the window, even with double glazing, then this is a good indicator that you have a lot of moisture in the atmosphere which will tend to condense out on the coldest surfaces (ie - corners of rooms etc). Obviously the way in which people live has a bearing on moisture, like if you have a family taking loads of showers etc. Dehumidifier are become quite popular these days for use in the winter months. 
Kevin 

['The Gaffer']

Thanks again guys. I like the sound of a heat exchanger system, there does not seem to be a lot to them but some are pricy for what they are. Sadly a de humidifier is not an option as it puts responsibility on others to operate it.

[Iancider]

Phil,
The humidity/lifestyle thing is quite likely especially if the place is not centrally heated or heated infrequently.  There has to be a source of humidity and that can be due to people drying washing indoors and also suspect are hidden leaks.  I saw exactly this issue at my Mother's house and it turned-out to be a slow leak of about one drip per minute  for four years under a suspended floor.  The lifestyle issue may well come from indoor drying - a friend did this and ended-up with mould all over the walls.  A dehumidifier works well and can be a permanent installation plumbed into a drain.  You could make it a lease condition that it is used if they must dry washing indoors.  They cost about £3 per week to run but are very effective.

Note one drip of water will expand to 2000 times its own volume in dry air.  In a small space only about 2-3 litres of water is required to saturate the air and cause instant condensation as soon as the temperature drops.  Black mould stains permanently and is hard to kill.  It normally needs redecoration after strong fungicide.  Normal humidity in the UK is circ 55% but inside houses it is often higher.  Black mould smells peppery and is bad for health.  If you sniff the edges of carpet you will probably smell fungus which can reek.  Cheap trick for a quick fix:  When the temperature is frosty outside open all doors and windows and move everything absorbent outside - humidity is very low and it will dry out quickly.  If you cant diagnose it PM me and I will come along and take a look.

Regards
Ian 

['The Gaffer']

Cheers Ian.

I have had someone take a look and they are convinced it is condensation rather than rising damp or the like.

Agreed, lifestyle can play a large part and I have discussed this. I have three options and because the problem is so small i.e no black spots on walls or ceiling but a small amount on the back of a bedside cabinet, now thrown out, and one or two on a pillow.

The room needs ventilation so I am either going for a small Positive Input Ventilation system, a single room heat recovery system, or a humidity controlled trickle extractor fan. Biggest issues are noise and the need not to blow cold air into the room.

Your thoughts?

Do you work in this field or just knowledgable?

[benchmark51]

I have an extractor fan in my bathroom, about 6 inches square that is 'on' permanently. It only extracts when I use the shower or bath. It is switched by sensing the steam from the shower or bath. Might be worth finding out if it could adjust to work in your situation. My smoke alarm is so sensitive it goes of if you fart!

[Iancider]

Phil,

I am a keen DIYer and I have dealt with every alien life-form in homes over the years.  You give a good indicator in your comments.  The most likely place to find black mould is on back to the wall cabinets and often in kitchen cabinets.  The wall is cool and causes a chill-off and condensation.  The favoured surface for mould is wood.  So I think this is a good indication if that is the limit.  Sometime leaves, insects and the like block them and on older properties they just aint there. 

Regards
Ian

['The Gaffer']

Phil,

I am a keen DIYer and I have dealt with every alien life-form in homes over the years.  You give a good indicator in your comments.  The most likely place to find black mould is on back to the wall cabinets and often in kitchen cabinets.  The wall is cool and causes a chill-off and condensation.  The favoured surface for mould is wood.  So I think this is a good indication if that is the limit.  Sometime leaves, insects and the like block them and on older properties they just aint there. 

Regards
Ian

I have an extractor fan in my bathroom, about 6 inches square that is 'on' permanently. It only extracts when I use the shower or bath. It is switched by sensing the steam from the shower or bath. Might be worth finding out if it could adjust to work in your situation. My smoke alarm is so sensitive it goes of if you fart!

Yes I have decided on one that is fully adjustable, it will be set for trickle venting 24/7 but will respond accordingly to changing humidity levels. Clever things.