Damp and what the correct next steps are?

Reply to the comment left by "Robert Desbruslais" at "12/12/2015 - 12:57":

I think the OP has vanished but they talk of a 2 bed terrace where they added a DPC.

Likely that this is the classic "refurb" where an old house has had plastic windows, a nice new kitchen with a cooker hood that recirculates rather than extracts and been let out to a tenant who doesn't want to spend all their excess cash on heating.

Insulation to eliminate cold spots would mean EWI that has no grants any more plus ground floor insulation that's impractical during a tenancy.

Ventilation, however, is perfectly practical and affordable to add while tenanted and should remove much of the problem at source.

Trickle vents are needed to "make up" for the extraction and its sad to see how many older houses have the airbricks blocked up or plastered over and then UPVC windows added without vents.

Reply to the comment left by "Renovate To let" at "12/12/2015 - 13:08":

Totally agree. It is all about ventilation. If your tenants do not agree they are welcome to pursue advice from our surveyors on the askasurveyor website.

What are the tenants like,do they want to move ,as many have said ventilation/heat will reduce many issues of condensation /damp. personally at this stage i would be drafting up all the info you have on the condition of the property since they have been tenants. visits to the flat ,photo,s taken as i think the ENVIROMENTAL HEALTH will not be far away and you therefore need to be ready to explain why you think this has occurred.Many say get trickle vents ,more air vents these are great if the tenants just leave them alone and not block them up .I had this issue once and when the E.H.O.went round he found that they were using a CALOR GAS HEATER in the flat which wasn,t allowed on the tenancy as storage heaters were installed (no gas). he informed me most of these issues arise through living styles and adults produce a litre of condensation per day and if it can,t escape it will go to the coldest wall in the flat. p.s you don,t hear of many issues of damp between march-october so maybe its just down to EDUCATING THE TENANTS .

Reply to the comment left by "John Hart" at "09/12/2015 - 08:08":

We had similar situation in one of our rental properties. We bought a hygrometer to test the humidity level and it recorded levels over 75% RH in all the rooms. We also had lots of cold spots as the property doesn’t have a cavity.

To get the levels down we installed PIV system (Positive Input Ventilation System). Initially we spoke to Environvent but they wouldn’t fit one because we had sarking and not a breathable membrane under the tiles. They insisted we fit ventilation roof tiles in the roof before they would install the system. This happened in December last year when the weather was really bad with gales and flooding and our roofer had to cancel doing the job 3 times.

The speed things up we decided to install the system first and sort the roof out later. Environvent wouldn’t install it without the roof being done first so we decided to fit a Nuaire, Drimaster Heat Positive Pressure Unit. It cost £320 supply only from the internet and our electrician wire it up £65. It works by drawing draws fresh air in from the loft space at a lower humidity level and pushes it through a vent in the hall ceiling, which in turn dilutes the humidity levels in all the rooms.

Once the unit had been fit we washed every speck of the black mould of the walls, wardrobes and windows with Dettol mould and Mildew Remover so we would know if it came back. We couldn’t believe it the problem went immediately away and we didn’t even need to install the ventilation roof tiles.

One year later and no sign of back mould. We have been amazed how effective this system is. In my opinion this is an amazing bit of kit, relatively cheap and well worth giving it a go.

Regards

Reply to the comment left by "Helen " at "12/12/2015 - 21:37":

I've considered one of these but I'm concerned about the air quality in the loft. It's full of black choking dust. I'd also be worried about any moisture going in the loft causing mould problems in there. I'd be interested to know whether these concerns are reasonable and what experiences other people have with similar devices that don't go through the loft.

The loft must be ventilated otherwise condensation will form on the sarking felt, and drip onto the insulation. Mould will form on stored effects in the loft.

Has anyone used the Schrijver System that was developed in the Netherlands? http://www.schrijversystem.com
I would appreciate knowing the opinions from those with first hand experience of this system or at the very least from those that have the ability to understand how it works & whether you think its purported effectiveness holds water.

the PIV units take air from the loft and raise pressure in the house to help push air through the walls/vents taking moisture with it. They do not add moisture to the air in the loft thereby causing problems . They take air from the middle of the loft space by hanging the input from a beam so not disturbing dust in the loft.
Most lofts are already ventilated at the eaves and at the ridge to reduce likelihood of strong winds blowing roof off.
I have a house with a humidistat controlled extractor in the kitchen (which I suspect tenants turned off) but after fitting a PIV unit we managed to stop the mould forming.(tenants would have to go into loft to turn off PIV)
In my own house I have whole house ventilation and heat recovery - works a treat!

All my pre 1980s properties have lap vents added in the loft - they simply fit where the impervious felt overlaps and open up the lap to allow air through. My experience has been that they totally solve roof space condensation (caused by moist air percolating through the upstairs ceilings and gaps and then encountering very cold air caused by the current 300mm insulation) with no need to disturb the tiles or slates. The tiles or slates provide plenty of gaps to feed the vents.

While vent tiles are easy to retrofit, they are often a very different colour and so become quite an eyesore until the passing of time weathers them in.

Reply to the comment left by "Sam Addison" at "13/12/2015 - 12:00":

Yes it's a good system especially with filters. I saw one instalation that was used to overcome allergies and it worked very well.