Damp and what the correct next steps are?

‘The only way of managing the problem is by ensuring moisture is expelled to the exterior.’

VENTILATION IS IMPORTANT BUT NOT THE SOLE WAY OF MANAGING CONDENSATION. THE OTHER FACTORS ARE:
– ADEQUATE HEATING
– REDUCTION OF MOISTURE SOURCES
– INSULATION
AND CONDENSING TUMBLE DRYERS ARE BETTER IMO.

Reply to the comment left by “Joe Bloggs” at “12/12/2015 – 10:31“:

Joe, shouting in capitals really isn’t needed.

The reason I concentrate on building “effortless” ventilation into my properties is that you cannot enforce 1,2 or 4 in your shout list and the water vapour produced by living has to get out of the building somehow, regardless of heating or insulation levels.

Designing the property for living is less painful than trying to influence (as you can’t enforce other than evict) how your tenant lives day to day.

Reply to the comment left by “Robert Desbruslais” at “12/12/2015 – 09:47“:

It may be better to purchase a condensing tumble drier which will warm the property without the added humidity.

Reply to the comment left by “Renovate To let” at “12/12/2015 – 10:48“:

NOT shouting. upper case obviously differentiates the quote from my comment. and if i want to use upper case thats my decision!
you CAN control the other factors, eg LL can upgrade insulation and warn tenants about heating and moisture sources.

Reply to the comment left by “Joe Bloggs” at “12/12/2015 – 10:55“:

Warn – yes. Enforce – no.

And you still need the water vapour to leave the house by some means, regardless of insulation and warmth.

Reply to the comment left by “Renovate To let” at “12/12/2015 – 11:03“:

I have been trialling the dual speed extractor in my HMOs – they run all the time very slowly and inaudibly then speed up if the relative humidity rises above the preset level. They are very good and keep the ensuite rooms fresh rather than “fruity”..

I’ve a granite walled house and having the same problem. Done my research. Problem I have is gypsum plaster stopping the moisture exiting through the naturally porous granite. My quick fix solution is to install a spacer into double glazed unit so window can only lock in the ‘ajar’ position. Monitoring this at the moment. If it needs more help then I am hacking off the plaster underneath the window where this mould occurs (Thinnest part of the wall). Repoint with lime mortar and leaving as a feature. If it doesn’t look good then I’ll plaster with a lime based plaster and a breathable paint which is compatible with old style plaster. Lime wash was the old breathable solution.

If this doesn’t work, I’ll fit a ventilator. Some would argue for a ventilator straight away and it may be the best solution in new houses. Old houses need old solutions. These problems were solved years ago, but new materials and building practices have blinded us.

Reply to the comment left by “Joe Bloggs” at “09/12/2015 – 09:34“:

This is incorrect. The higher the temperature the more moisture can be held in the air and the greater propensity for condensation when the air hits a cold surface. Moisture must be extracted. The ideal is a combination of insulation and ventilation. This creates comfortable conditions without excessive fuel bills.

I THOUGHT SOMEONE WOULD DISAGREE BUT HOW DISAPPOINTING ITS A CBS.
‘The higher the temperature the more moisture can be held in the air…’
CORRECT
‘and the greater propensity for condensation…’
NO. TAKE A STEAMING KETTLE. THE STEAM WILL BE IN THE AIR REGARDLESS OF AIR TEMP. HOWEVER IF IT IS COLD THE STEAM WILL CONDENSE ON A COLD SURFACE. CONVERSELY IF THE PROPERTY IS HEATED THE STEAM WILL BE HELD IN THE AIR LONGER, THERE WILL BE LESS COLD SURFACES (I.E. BELOW DEW POINT) BECAUSE THESE SURFACES ARE HEATED UP (BY THE HEATING) AND BECAUSE THE MOISTURE IS HELD IN THE AIR (RATHER THAN ON THE COLD SURFACES) VENTILATION IS EFFECTIVE IN EXPELLING THE MOISTURE LAIDEN AIR.
‘Moisture must be extracted…’
YES, OR ALLOWED TO MIGRATE TO THE EXTERIOR AND AS EXPLAINED ABOVE THIS IS EASIER TO ACHIEVE WITH HEAT; FOR CONDENSATE TO BE REMOVED IT FIRST HAS TO BECOME AIRBORNE WHEREAS IF ITS IN THE AIR ALREADY THE REMOVAL IS OBVIOUSLY MORE DIRECT.
‘The ideal is a combination of insulation and ventilation. This creates comfortable conditions without excessive fuel bills.’
AND ADEQUATE HEATING FOR THE REASONS SET OUT ABOVE.

We will have to agree to disagree Joe. In 25 years of surveying I have learned there is no substitute for a good balance of heat and ventilation. Furthermore, tenants do not all want to maintain a high temperature in the home. Over the years tenants have been blamed for creating condensation problems. However, they are warey of high heating bills. By installing appropriate insulation, landlords can encourage the tenant to maintain ventilation without risking wasted heat loss and higher heating bills. A humidistat with a heat exchanger will also be effective. Simply turning the heating up without maintaining ventilation is a recipe for condensation.