German housing and mould

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Posted

Does anyone know whether there's a particular problem with the construction of housing in Germany that encourages the growth of mould or mildew? From what I've heard, it can be a problem with houses and apartments here, sometimes even when they're new and well-heated. Since I'm considering buying an apartment, I want to know what to look out for in terms of the construction of the building.

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Posted

From your profile it doesn't state where you're from, but I don't suggest going to England. Never saw so much mould. Old housing stock will do that. Number one tip for min. mould would be a ventilated building. On the exterior of the building you will see vent bricks (or similar if rendered). These vent the cavity in the wall which will help minimize interior mold.

The biggest way to minimize mold is as just about every german rental contract states: ventilate. Especially when creating steam, such as cooking or showering. Still boogles my mind why people wonder why they have mould in the shower when they've never opened a window!

Edit: should also add stay away from buildings with only single glazing, the windows will condensate really badly in winter when you turn up the heat and create nasty black mould. Preventing mould is a combination of how the building was built and maintenace after.

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Posted

In my experience, it's the hot summers. As soon as the outside temperature goes above 25°C, the Relative Humidity inside goes up to 65 or 70%. So, yes, ventilation is the answer in winter, but when it's hot the only answer is a dehumidifier.

That said, properties built on damp ground, e.g. a flood plain or close to a stream, will be more susceptible to damp. No doubt the quality of the building work will make a difference here. But in the UK some form of damp is pretty much expected in any property, especially older ones. Get a survey done before signing anything and that should flag up any problems.

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Posted

All buildings that have basements must be waterproofed according to building regulations. This is especially true for buildings that are built on ground with high tables. This can be retrofitted, ie, you can get your basement tanked after its been built. Highly adviseable as moisture will travel up the building.

Definitely agree about the dehumidifier, some regions get really humid. In my last flat in Baden Baden the humidity in summer was 70-80% and in winter it was 30%. The flooring was moving like you'd never believe! I now both humidifier and dehumidifier.

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Posted

The thing about new buildings of course is that they are often relatively air-tight (modern windows and doors not sash-frames and draughty old doors, concrete floors not floorboards etc). Apartments often do not have "one-end-to-the-other" ventilation (front to back door either). Then you can add interior bathrooms that have no windows. And people's inclination to keep windows shut when it is minus 20 outside in winter etc.

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Posted

We ended up paying to rid our Altbau bathroom of mold when we left Germany. The bathroom had no ventilation system, and we were supposed to have kept the bathroom window open in winter to prevent mold. The bathroom had no heat, either. :blink:

Anyway, it's the airtight buildings that contribute to the problem. Minnesota also has high humidity in the summer. When we were house-shopping here, we were advised to look at the inside of the window sashes for evidence of condensation, which would mean that the house is too air-tight and there would be mold problems. For awhile, it seemed like a good idea to build houses as airtight as possible against the bitter Minnesota winters, but that idea was misguided.

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Posted

Experiences vary from person to person more than from continent to continent apparently. There was nowhere, or no house/flat that I've lived in ever had this damp although I have come across it in a rare couple of cases in England (not in Wales or Scotland) and in a complete slew of cases in Germany. The reason in my experience that British buildings, whether built in 18th - 19th century or as recently as 1970s, seemed to be free of it were the non-airtight closures. Slight draughts around windows and doors which were controlled by heavy curtains or drapes were a virtual blessing and a technical necessity where either open coal fires or even gas-fired central heating was standard. An airtight building would be a deathtrap because of carbon monoxide poisoning and efficient smokefree burning of coal requires a good supply of oxygen to work.

The slew of cases in Germany I mentioned were all former US Army buildings which ranged in age from a small former Schloss built in the 17th century to the most modern garrison in Europe built in 1985. Due to the rapid movement of troops from Germany to the Persian Gulf theatre in 1990, the reassigning of their families to the USA and the erratic planning of the post-Cold War drawdown some of this real estate was locked and sealed and left un-maintained for 6 - 24 months prior to clearance of furniture and equipment and handover (in repaired condition) to the German Bundesanstalt für (forgot the name here meaning real estate was NOT immobilien) Egalwasesheißt. Many barracks were evacuated so rapidly that fridges with KFC or McDs food were left without power. I won't disgust you with details. Shower facilities, washing areas and so on with small leaks and dripping taps had caused, in locked buildings, damp to spread over several floors and made clearance work without facemasks quite dangerous. Really bad examples of wasting public funds were such thing as autumn leaf blockages causing backing up of drains over 2 years, similar roof downpipe neglect and even relatively young 3storey buildings being rendered demolition ready by the simple fact that trees had been planted too close and growth not managed resulting in several cases of us finding 15 meter long and 20 cm wide cracks.

All of this building stock had to be reinstated to a specific architectural standard at US taxpayers expense prior to acceptance by the Bund. Post takeover of the real estate the Bund, who themselves had more real estate than they were able to maintain and no plan to manage the rental or sale commercially, continued to neglect most of these billions of Euros worth of taxpayers assets. Few of these assets have ever been put on the market efficiently, many were indeed demolished and cleared to leave nothing but wasteground. I often wondered whether the taxpayers of the USA or the BRD who had not an iota of an idea of such waste would have actually cared if they had known. Oh well, simply ruminating about it now, but it used to infuriate me back then.

So for the OP my tips. Make sure you don't buy any real estate until you have a trustworthy architectural engineers report on it's condition. The report should be very comprehensive including details of heating equipment and age, ventilation, draughtproofing, roof, door, window and wall heat loss profile etc. There are specialised firms in every city in Germany offering this service. Ask your local Handelskammer for approved trade organisations recommendations. Also worth looking into is Passiv Häuser. These are low maitainance and fuel consumption houses which rely on such natural sources of heat and power as Solar and ground heat transfer allied with hightech heat and ventilation managment. Initial costs are higher than traditional buildings, but annual fixed costs are considerably lower.

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Posted

Does anyone know whether there's a particular problem with the construction of housing in Germany that encourages the growth of mould or mildew?

Its not a bug, its a feature. Modern German hosue are built o such high insulation standards that they are effectively airtight and so, of course, they need careful airing (or, like a couple of new places Ive looked at recently, conrolled ventilation systems).

90% of mould is due to people just not opening their windows enough. Damp is something different entirely and should only affect older palces or badly built cellars.

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Posted

It is true that lack of ventilation causes mould, but the main reason there is mould everywhere is that when the old paint which contained lead was banned, people failed to implement correct practice for painting with the new enviromentally friendly paints. Before you paint you should prep with an anti mould-fungus coat layer, very few people go to the bother of doing this, as they are lazy and want to save money.repainting every year also prevents mould build up

Also all hard surfaces like tiles etc, you can purchase anti mould-fungal products to get rid of this, washing up liquid works just as well !.

For stone walls. in old buildings, such as sand stone you can buy sealers and apint them on, this prevents any problems

These problems are minor to deal with and general good maintainence should deal with them, you are probably experiancing more of this in Germany as you are probably visiting more rented accommodation, with bad maintainence, back home you probably visited people who owned their own home and cared for it more! I would be willing to bet that private owned homes in Germany do not have this problem.

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Posted

We had this in our last UK house - which was about 10 years old, and not very well built/insulated. It only happened on walls where the sofa/cupboards had been pushed up against it, so make sure to leave a decent gap when placing stuff against walls. The walls in question were all the ones which had the extenal wall on the other side, never happened on the partitions. I think the problem started after we had a baby, drying all the washing indoors on radiators and such while not venting the house well. A dehumidifier is good for drying washing too. Now we vent as much as possible; at least daily, even in deep winter.

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Posted

Also a big problem: If you install new windows without adding insulation to the outside walls of the building.

By this you

1) have an air-tight house and

2) you still have cold walls inside which the moisture condensates.

If you insulate on the walls' ouside then the condensation point will move to the outside, too, behind a to-be-installed moisture barrier. If you then open the windows regularly everything will be OK.

If you want to add new windows without insulating the walls consider an active ventilating system (costs: app. 3000-10000 €).

If you consider buying do what 2beornot2be said: get an expert to report on the building. The TÜV apparently stocks them, just call.

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Posted

Houses with the highest energy-efficiency (i.e. the most airtight ones) are usually advertised as "KfW70-standard" or "Passivhaus". For these houses, an automatic ventilation system is nearly always included in the design, because otherwise they are practically guaranteed to become mouldy (not to mention stuffy). For all other well insulated houses, opening all windows several times a day for 10 minutes (even if it's freezing badly outside!) is apparently the minimum requirement to keep mould at bay.

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Posted

@ tom a sorry mate but we have suffered a bit from this too.Opening the windows in winter is not really a good idea as the warm air condensed in to water when you do that.What i did after some advice from a builder i know in England was:-

1. Wipe of the mould with a damp cloth.

2. dry the patch with a dry cloth.

3.Sprayed the patch with Schimmel Vernichter and at the same time rubbing it in with an old nail brush.

4.Left the patch to dry off naturally for about an hour.

5.Repeated step 3 again.

was ok then.

Painted the complete apartment this year and put in an additive for damp.Can get all thsi stuff at any Baumarkt.Seems to have worked anyway.You can also get some plastic boxes with stuff in it that take all the excessive moisture out of the air

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Posted

My friend's husband who works in the building industry told me that part of the problem is also that new buildings are not left to dry properly after building, so the building moisture aids a buildup of mould. (Hopefully I am remembering this correctly as I generally have no clue about the building of houses.)

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Posted

To avoid mold:

1. buy hygrometers for all your rooms

2. when the temperature in your apartment/house is 20°C

measure the temperature of the walls.

If you see temperatures below 13° you can expect problems

with mold, if the humidity in the room is above 60%

(because the humidity at the cold spots will be more than 80%)

->increase the room temperature, vent more, sell or move

3. don't switch off the heaters in the bedroom and leave the door to

the other rooms open. Warm,moist air will flow into the bedroom and

condense at the cold walls.

In summer a high humidity is no problem since you have no cold spots where the humidity would increase.

"Opening the windows in winter is not really a good idea as the warm air condensed in to water when you do that."

That is nonsense. Warm air will only condense on cold surfaces. The inetrior walls are warm.

What you do by venting is replacing warm/moist air with cold/dry air.

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Posted

When your shopping around for a house of Flat, make sure that the building isn't damp proof.

We have an old Vic flat in London and discovered that the worst thing you can do is use the damp proof stuff.

The reason, the building needs to breath.

Ask if the property your looking at has been damp proofed.

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Posted

I have never seen a building that breathes!

If you want a building with holes in tzhe walls you have to pay a horrible heating bill.

When you want to waste energy, a nicer way is to drive 250km/h with a large SUV on a German autobahn.

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When cold air come in hot air goes to top.As cold air moves in warm air drops.Meets cold air and leaves moisture in air.Like i say we tried all this and it kept coming back.Now done it the way i have written no more problems.Proof is in the result???

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Posted

You mean you now always keep your windows closed in winter and hardly ever open them?

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My friend's husband who works in the building industry told me that part of the problem is also that new buildings are not left to dry properly after building, so the building moisture aids a buildup of mould. (Hopefully I am remembering this correctly as I generally have no clue about the building of houses.)

When we moved into our (new) house there was a big sign on the floor telling us to ventilate ell during the first year.

Ventilating helps in winzter ayway, as the build-up of moisture inteh air makes it more difficult to heat.

Id had never seen one of tehse controlled ventilation thingys before, but two of the Musterhäser Ive looked at recently had one - I like the idea.

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Posted

Tom a, we open windows but central heating is turned off close windows and then slowly turn the heating up to heat air

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Posted

I'm pretty sure we have mold in our kitchen drain. Is this because we are nasty m*****f***ers or has anyone else had this problem?

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I'm pretty sure we have mold in our kitchen drain

Does your husband drink a lot of beer at home, and is the kitchen nearer to the TV than than the toilet is? If yes, he's been pissing in the kitchen sink.

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No, he drinks beer rarely if at all, and almost never at home, so while the kitchen sink is indeed closer to the living room than is the toilet, this hardly seems likely. Urine also seems like something I might pour down my drain in order to wash away, sterilize and deter the growth of mold. Maybe I should ask him to start pissing in it and see if that helps.

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