Dampness and condensation

[gazid]

Hi all,

We have had damp in our walls in the kitchen for some time now.... Had a visit from a Damp proof specialist.

Previously, our land lord had put a vent into the bottom of the wall. The damp proofing guy said that this let cold air in through the bottom, which meets warm air at the top of the room, creating damp. Makes total sense.

He also said that the plaster that had been used in the walls was the wrong kind and that it simply soaks up the moisture, resulting in the damp, a bi product of which can be black toxic mould (he used a machine to measure damp levels, the reading was in the red. Normal levels should be up to around 4. These were around 7-8).
Obviously the damp and mould has health implications. I work from home so am here a lot and have actually been feeling run down, with cold like symptoms for over a year and a half..... I have had no alternative but just to shrug it off.

In any case, the contractor said that the solution was to strip all the plaster off to the brick work, replaster with a sand and cement render, brick up existing vent. New vent blocks in top of wall and a 'lofty'/ ceiling fan in roof to ventilate.

Ball park figure at the mo is £3000 + . I imagine a hard time with the land lord trying to get him to part with this.

I will prob get a 2nd estimate also, just to compare. Any thoughts would be appreciated.

The Damp proofing guy really seemed to know his stuff and I believe what he is saying but any thoughts/input would be appreciated.
Especially in regards to the validity of the work I was told needs doing.

Thanks in advance

 

[JohnD]

first question to anyone with condensation: Do you drape wet washing about the house?

this is the top one. Nothing else comes close

second question: When do you open the windows, and what other ventilation do you have??

third question: how long to you run the bathroom extractor fan during and after every bath and shower?

fourth question: how long do you run the kitchen extractor fan during and after cooking or washing up?

fifth question: have you got an unvented tumble drier?

be aware that damp companies are in the business of making money by selling damp-proofing treatments.

more info on //www.diynot.com/forums/viewtopic.php?t=239112

btw

... our land lord had put a vent into the bottom of the wall. The damp proofing guy said that this let cold air in through the bottom, which meets warm air at the top of the room, creating damp. Makes total sense....


...The Damp proofing guy really seemed to know his stuff ...

if your damp-treatment salesman has told you that ventilation causes condensation, he is talking absolute, total, 100%, nonsense

 

[Nige F]

If your landlord wants to part with £3k - for that work . Tell him me and my son ( plasterer) will come and stay in London and re render/ set the whole kitchen for £2.5 k CASH , No reciept or " gaurantee" . You got 2 choices . John D or the knowlegable salesman

 

[ajrobb]

Rule of thumb - salesmen tell you their product is perfect for you.

Damp is often caused by condensation, especially in kitchens and bathrooms. Most kitchens and bathrooms have ordinary plaster - a sand cement render sounds ridiculous. As JohnD says, drying clothes on an airer (or radiator) dumps huge amounts of moisture into the house and cause condensation.

The old solution to condensation was a lot of ventilation and a little heat. The modern solution is more heat, sealing and insulation with just enough ventilation for health. Saying that ventilation causes condensation is rubbish. Try keeping the ventilator open and the heating turned on.

Plaster can be protected from absorbing condensation with a couple of coats of acrylic paint. This doesn't stop the walls dripping with condensation and growing mould on the surface, but it stops the plaster falling off and the landlord searching for a new tenant. Any mould can be washed off the surface. Within a year, the walls should dry out.

If you must dry clothes indoors (we do), consider a dehumidifier. I use one and it is very effective - towels and jeans dry overnight. If you don't want to splash that much cash, buy a hygrometer and measure RH in various places. Try it on the floor in the kitchen next to an outside wall and away from the vent. Readings below 60% are good.

 

[Static]

Damp proof specialist

specialist ... lol..

Anyways, so the cold air comes in at low level, heats up in the property so it can rise to the higher level and cools the hot air containing moisture at high level? Hmm.. these guys need to come up with some better excusses do make money from old rope..

All of JohnDs questions are very valid and im sure the "specialist" also asked them..

Can also add boiling a kettle or running a gas hob produce water vapour.. combined with drying clothes and washing machine/tumble dryers you get a pretty humid amount of warm air floating around your kitchen ceiling.. then if you are one of the millions who for some reason feel that windows should only be used to scream at the kids and dont leave them open 24/7.. then during the colder hours of the night the warm moist air cools releasing its water onto the closest cold surface.. normally the corners of external walls.. water stays there and mould will eventually spread in pretty black smudges.. if left unchecked for enough years can turn into nasty mould that roams the countryside killing rambler..

 

[jeds]

Changing the existing plaster for sand cement render/plaster is a waste of time and money and will have no effect whatsoever on the condensation issue. If the plaster has really gone bad and cannot be recovered I would advise replacing with a good quality renovation plaster, not sand cement.

Whether you block the vent or not is a side issue really but if you do you must make sure it is not an essential air supply for a gas appliance. Venting at higher level is better. Trickle vents on the windows are good. Opening windows regularly is also good.

You don't mention if you have an extractor fan. If not this is the first thing to fit. Make sure it is a good one with a timer overun.

Personally I would treat the plaster, paint with an anti-fungal paint, fit the extractor fan and see what happens.

Also, JohnD's advice is all good and you should follow it.