What type of damp is this???

[Beardo]

Hi all, 

 

Looking for a bit of advice from some of the more knowledgeable members on the forum. We've been seeing this problem for a while now and I believe its getting progressively worse. Not sure if this is rising damp, condensation or something else but before I call in any specialist to be told I need a really expensive damp proof course, is there anything I can do as a DIY measure to stop it? 

 

House is on a hill and we do have a cavity under the ground floor - not sure if there is water being built up but could be a possibility. Additionally, the outside could do with some of the brick work/mortar being re-layed and re-pointed. 

 

I've included a few pics taken from the hallway, this is the worse patch. Its an external facing wall with a shoe cabinet in front. The others are from around the house including the living room, a dining room on both the external facing and internal walls. 

 

Would appreciate any advice really as I'd like it sorting asap.  

[Beardo]

[SteamyTea]

Look for any sources of liquid water.

These could be water pipes, gutters, down pipes, ground level above a damp proof course.

Condensation is generally caused by a cold internal wall, so may be low levels of insulation, or very high humidity, as in a bathroom.

[kandgmitchell]

Assuming there's no obvious ingress of direct water from outside - (as ST says, check for leaking gutters etc) then this looks like classic condensation. Corners and the bottom of walls are colder, condensation happens often without even being obvious. Dust in the air sticks to it and mould grows on the dust in a damp environment. Still air behind cupboards and the like makes it worse. First job is to kill the mould so it doesn't just grow back. Curing structural condensation is not easy. You need to reduce the moisture content in the air whilst getting those colder surfaces above the dew point

[ProDave]

If it is condensation, then I would expect it to have dried out completely over the summer as the walls will not be cold enough to be below the dew point.

 

Do NOT invite a "damp specialist" around.  I have yet to hear a good outcome from that.

[Beardo]

8 hours ago, kandgmitchell said:

Assuming there's no obvious ingress of direct water from outside - (as ST says, check for leaking gutters etc) then this looks like classic condensation. Corners and the bottom of walls are colder, condensation happens often without even being obvious. Dust in the air sticks to it and mould grows on the dust in a damp environment. Still air behind cupboards and the like makes it worse. First job is to kill the mould so it doesn't just grow back. Curing structural condensation is not easy. You need to reduce the moisture content in the air whilst getting those colder surfaces above the dew point

Would adding trickle vents to the windows help? A little lost as to what do here, defo got a moisture issue as I've been using a monitor to track moisture levels within the rooms. 

[JohnMo]

Is your ground levels below the damp proof course? Have you done any landscaping outside that may have changed ground levels?

 

What ventilation measures do you have?

 

How long have you lived there?

 

Is this a recent thing or been there quite awhile?

[Beardo]

1 hour ago, JohnMo said:

Is your ground levels below the damp proof course? Have you done any landscaping outside that may have changed ground levels?

 

What ventilation measures do you have?

 

How long have you lived there?

 

Is this a recent thing or been there quite awhile?

I believe there is a damp proof course. No landscaping done and I have lived in the property approx. 7 years. Renovated the whole house before I moved in. 

 

Ventilation measures is simply opening windows during the day in the rooms where it is worse. But difficult to do so during winter as the house is not easy to keep warm. Did not have the trickle vents installed when having new windows fitted. 

 

Its progressively got worse over time. 

[kandgmitchell]

Well I'd put my money on condensation. Penetrating damp would disrupt the plaster and leave a stain over a defined area as it soaks the wall. This looks like mould spots across a damp surface. This is a classic conundrum with modern life in older houses, lots of warm moist air and poorly performing thermal envelopes. You can't use the windows in the winter when it is most critical to remove the moisture laded air. Usually it's the colder surfaces in upstairs bedrooms that suffer the most. The first job is to kill the mould, the second is to get rid of the worst damp air at source so extracts in the bathrooms and kitchen are a must. You may want to consider a cheap dehumidifier. Going beyond that isn't easy as putting in trickle vents now isn't simple nor is insulating the walls.  So the easier bits first.

[JohnMo]

You need a decent method of cross ventilation, so air is allowed to come in the dry rooms and is sucked out of all wet rooms.

Extract - dMEV fans cost almost nothing to run, Greenwood ones come up on eBay quite often for not much money they will react to rising humidity. MEV is a central unit if you have easy access to run ducts.

 

Supply - You have two options retrofit trickle vents to dry room (not wet rooms) windows or through wall. Through wall humidity activated vent something like this 

https://www.bpdstore.co.uk/glidevale-fresh-99h-humidity-sensitive-wall-ventilator/p/231

 

Their trickle vents

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

 

Other makes and models are available.

 

So you need an air inlet in all dry rooms, bedroom, lounge etc

An extract fan in all wet rooms, bathrooms, utility, kitchen etc. The fans run at a very low flow rate 24/7.

[Jilly]

You could also get a dehumidifier, Meaco are good. You can buy packs of humidistats on Amazon cheaply to put in each room so you can monitor things. 

[Dave Jones]

could install a loft unit to force airflow

 

https://store.beamcentralsystems.com/products/axco-loft-mounted-positive-input-ventilation-piv#:~:text=Designed to run continuously%2C the,generating fresh filtered air throughout.