Damp or poor ventilation?

neil_9999

Hi all,

We have recently moved in to a house. The survey said the ground floor is riddled with damp - though I have my suspicions. The wallpaper feels like it has been wet (sort of stiff) and is cold, but nothing is wet, no watermarks or anything. There has been no remedial work.

However, condensation literally pours off every window in the house (which are single glazed uPVC), causing mould around the frames. The exception is one double glazed window downstairs, which is fine. Opening all the windows does a good job of stopping the condensation but obviously the house gets incredibly cold.

The upstairs bathroom is the exception - condensation literally runs down the walls after a shower and causes mould patches everywhere, regardless of leaving the window open.

We do use the radiators to dry clothes and the problem is present even if we don't.

So my question is, do you think there is a damp issue or ventilation issue? I want to sort the problem, but want to make sure I go the right way about it. Not sure if it makes any difference but the walls are solid stone (it's a traditional welsh valley house).


Thank you!

David_Aldred

How old is the property please ?

neil_9999

Not sure of the exact age...but around 100yrs

phill99

If it's condensation, then it's a ventilation issue combined with excess moisture in the atmosphere. Get an extractor fan fitted in the bathroom and kitchen stop drying clothes on the radiators. Buy a dehumidifier.

David_Aldred

Hi - condensation is a form of dampness, indeed statistically around 70% of all dampness problems seen are thought to be condensation related. Your surveyor may well have used an electrical damp meter to sample the wall surfaces and it is the pattern of any high readings from such meters, along with other tests that will assist in making a proper diagnosis as to whether there are other forms of dampness present other than condensation to this property.

Solid external wall properties are inherantly prone to both some degree of penetrating damp and condensation. From the age of the property it should have been built with a damp proof course under public health legislation / Building Regulations.

Think how was the property originally built ? How was it designed to originally function and what perhaps has changed over the years which may have altered that design perhaps not always for the better. For example open fireplaces now sealed up, double glazing lacking trickle vents, hard dense cement renders / cement mortar re-pointing restricting the way the property was designed to breathe outwards, raised external ground levels, non breathable roofing felts and insulation lowering the temps on the cold side of that insulation in some areas which may promote condensate to form where previously it did not.

Avoid heating regimes where the property is allowed to go cold for significant periods say at night whilst you are asleep or out at work - condensation being temperature related, provide background ventialtion that is controllable to each and every room, have humidistat controled extractor fans to kitchen and bathroom, use a condensing dryer for clothes, try and cook and bathe with the door shut and let the fan do its work to prevent warm moist air moving to colder areas and condensing out.

Clean mould down as soon as you see it - walls can be running with water and do little harm health wise but the products of mould grwoth can have an adverse impact upon your health so if you do nothing ensure the mould is cleaned down as soon as you see it.

If funds are available look at returning the external walls to a breathable condition if this has been adversely altered. Lime renders and mortars are far more breathable than cement mortars / renders. Lime also self heals minor cracks as rainwater washes over it which does not happen with cement mortar / render.

Application of clear breathable water repellants to the outside face of masonry which is just stone helps resist wind driven rain penetration. One may appreciate that if a wall has air within its pores it is warmer than a wall that has water within its pores and if a wall is warmer it is less likely to condensate.

By no means a complete list of issues but perhaps food for thought.

Kindest regards,

David Aldred - Independent damp, timber & wall tie surveyor

neil_9999

Thank you - useful stuff to look in to.

The house is rather "complicated" being halfway up a Welsh mountain.

It's nice to see a post that actually gives some useful information rather than open a window and contact a specialist!