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Faceliftw211

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Hi Guys, wondering if anyone can advise a cause/solution.
I have a first floor (top floor)flat rented out and for the last 3 years I have had tenants complain of damp and mould appearing in the top corners of various room's walls and ceilings, but only on outside walls.
This started the winter after after I replaced the old wooden frame windows with the latest sealed unit double glazing.....coincidence ??
Mould has also now appeared in one of the fitted wardrobes( top corner outside wall again). The tenants are all adamant they leave the trickle vents open and often even leave the windows slightly open also.
It cleans up with bleach and water etc but seems to return quickly.
Any ideas guys would be great fully received.
Thank you.
 
This started the winter after after I replaced the old wooden frame windows with the latest sealed unit double glazing.....coincidence ??

Thank you.

Not coincidence. Your new windows are far more draft proof than the old ones.

I'd query whether your tenants are ventilating the place enough. The more expensive way of dealing with it is with a dehumidifier - not great though as the tank will need emptying regularly.

Query also whether your tenants are drying damp clothing on the radiators?
 
What type of roof do you have? Pitched or flat.

A lot of damp can be caused by leaking rain gutters.

When were they last cleaned/ checked for leaks?

Is there a render coat on the external face of the property or brickwork?

How old is the flat?

Were the windows fitted correctly because if there is a bridge for moisture to travel across it will. How far away are the windows from the offending areas?
 
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Not coincidence. Your new windows are far more draft proof than the old ones.

I'd query whether your tenants are ventilating the place enough. The more expensive way of dealing with it is with a dehumidifier - not great though as the tank will need emptying regularly.

Query also whether your tenants are drying damp clothing on the radiators?

As davidjpowell says are they ventilating the property enough because even when its cold sometimes the best solution is to open the windows. In addition I do not believe wardrobes will ever be completely free from damp if they are built against outside walls.
 
Heating and ventilation are key - mould is a growth that thrives in damp, humid conditions.

Trickle vents are rubbish.

I've installed airbricks high up in the past, to provide permanent draught free ventilation.

You must remove all the mould with a proprietry solution as it won't disappear just because you've bettered the heat/vent - you must remove it.
There's lots on the net about bleach not being suitable for killing mould.
 
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How old is the property, does it have a cavity wall, if so have insulation installed as it will raise the internal skin temperature.

Also, is the loft void adequately insulated?
 
Definitely inadequately ventilated.

Mic
 
Definitely inadequately ventilated.

Mic

Most usual cause. Been through this a couple of times: older buildings struggle in this regard.

When you fit double glazing a number of things happen:

1. the building is more effectively sealed, so less airflow

2. Warm air holds more moisture than cold air, so the humidity level tends to increase

3. less water condenses on the inside of your new windows, so the warmer more humid air just dumps its water load any surface that is cold enough to condense it.

Solved our problems by fitting extractor fans in bathrooms and external venting of cooker hood but when it is really cold and windows are shut we run a small dehumidifier on the upstairs landing.

(Another misery presented itself in the form of condensationed/ice forming on the underside of the roof, so the answer there was to increase the loft ventilation)
 
(Another misery presented itself in the form of condensationed/ice forming on the underside of the roof, so the answer there was to increase the loft ventilation)

That normally indicates moisture is escaping from the living accommodation into the roof void.
If the ceilings and loft hatches are well sealed, no moisture will escape.
 
If you have a fitted wardrobe against an outside wall, you will have mould unless you have heating inside the wardrobe.
 
If you have a fitted wardrobe against an outside wall, you will have mould unless you have heating inside the wardrobe.

I have and I don't. Why's that?
 
For some reason, fitted furniture against an outside wall will draw moisture from the wall. The wall will always be cold compared to the temperature inside the fitted furniture. Suppliers of fitted wardrobes ( at least the good ones) will caution against fitting them against an outside wall unless there is heating in the wardrobe eg a radiator.
 
I have and I don't. Why's that?

You must have enough colder spots elsewhere, or the humidity is low in your house.

Our house has one end of a fitted wardrobe against an outside wall and anything touching the wall goes mouldy pretty quickly.

With just me & Mrs R at home now, I really noticed a difference when we had family staying over Christmas. The upstairs double glazed windows were streaming every morning.

The fairly still weather doesn't help either - opening the windows a bit at night just means they're the same temperature on the inside as they are outside, so they attract even more condensation. At least they're acting as a dehumidifer.
 
The point about ventilation is that in the room (or house) concerned is that the pressure within needs to be greater than the pressure without in order to maintain a continuous change of air. This is usually done through heating but it can be achieved using low voltage (inexpensive to run) devices designed to do the same job. Ideally you want air in at low level and air out at high level.

Mic
 
Since your flat is on the top floor i take it you have a loft so you could fit a heat recovery unit. They extract stale air from the house and bring in fresh air from outside via a heat exchanger.

Our new house has the old metal crittal windows that i love so im fitting secondry glazing in front of them with a heat recovery unit.
 
Thanks guys....looks like there is no single easy solution. Maybe an air brick at high level in each room, keep emphasising the ventilation point to the tenant, also a small electric heating panel in the wardrobe. I will use a specific proprietary solution to rub off what's there also..........then hope the weather warms up!!
I will go into the loft and also check to make sure there are no roof issues also.
 
I have a similar issue in a flat that I let out.

The block's built of steel reinforced concrete and has terrible condensation problems. I provide two dehumidifiers and have maintaining them written into the tenants' contract. I've had no significant problems over the last seven years.
 

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