Is this condensation a damp proof course problem?

[VivaLeBeaver]

We live in a 1900 semi. No cavity wall but there is a damp proof course.

We are good at ventilating the house, have a dehumidifier downstairs, don't dry washing in the house, etc.

Dh wipes any condensation off the windows every morning. He's concerned as he says there's more condensation in the living room than in the bedroom and there aren't two people breathing all night in the living room. Also he says the condensation is worse than it was a few years ago.

He thinks the damp proof course may need redoing. I'm not convinced. But if we get a company out to ask them they're surely going to say that yes it does need redoing aren't they? So not sure how to find out.

If you get one do shop around, I bought ours from bhs online and they had 20% offer on which they do quite often, the same model varied massively in price depending on where you got it.

Thank you, it was the dehumidifier :)
Need to research them - this cold snap has really worsened things.

The only thing it hasn't improved are 2 old metal frame windows we have by the front door, but they are little so I don't mind! The rest of our windows are upvc and they are fine now

I think Tricot has it.

Water vapour is lighter than air so it rises through the house until something stops it. So if there is excess moisture at the ground floor level, it is coming from somewhere. You should not need to use a dehumidifier unless something is wrong. Have a sniff under the floorboards, this is usually easiest in the cupboard under the stairs which rarely has carpet or laminate laid.

deciide where the incoming water main runs, it will most likely be buried between where the stop cock is, next to where the front gate used to be, and where the kitchen sink used to be. Some of your neighbours with identical houses might actually have the stopcock accessible, and not paved over; yours will be in the same place.

If it is a concrete floor, pull up the covering and see if it is damp. If wooden floor, look underneath in as many places as you can, and have a sniff and a look. If you get someone to turn off the stopcock at your boundary, or the meter while you have one, while you are in the kitchen in total silence, you may find that a faint hiss, that you'd never noticed before, stops. If you have a water meter, observe if the little bubble is always turning slightly.

If your central heating is topped up with water from a feed and expansion tank in the loft, do and look to see if the ball0cock is constantlt topping it up with a dribble or drip. You can put a bit of kitchen roll round it to see if it gets wet. If your CH is sealed, observe if it often needs to be topped up to repressurise it and replace the water that has leaked out.

If the condensation is worse in rainy weather, it might be that your drains are leaking; it might also be leaking bathwater and sewage. In a Victorian house built on clay, it is usual to find that the first elbow, where the vertical cast-iron downpipe meets the salt-glazed horizontal underground pipe, has fractured, either from the house settling into the ground, or from shocks caused during the 1939-1945 Unpleasantness. This causes the ground to be washed away and form a cavity, which might be under concrete or paving which will sound hollow until one day it collapses and falls imto the hole.

As you are in a semi, the water might be coming from one of these defects in your neighbour's house.

We've not got any leaks. The meter doesn't turn when all the taps, etc are off. Sewer pipe runs away from the house so doubt it's that but thanks.

Because its an old house there's no cavity wall. I think the condensation is down to the temperature difference from the outside to the inside. I think dh is wrong that a new damp proof course will help.

One thing I've realised today is that we've only recently got a door for the living room which is now shut at night to stop the dog going in. I think this is why the condensation is worse as the air in there won't be getting sucked into the dehumidifer. Makes sense to me but dh disagrees!

Go outside when it is raining and check all rainwater is flowing away and no damp patches on brickwork etc. We had terrible problems in a Victorian house just because some of the lead flashing had moved. So small but created a big problem.

We had a positive flow ventilation fan put in our loft in a Victorian house that had uPVC windows

It stopped the condensation on the windows over night - it cost about £150 to put in & the same as a light bulb to run

But we did heat the house well & my dad (a structural engineer) says ventilation & heating are they only way to reduce condensation

are you willing to look and sniff under the floor?

I have terrible damp and condensation. I regularly have to bleach my bedroom wall and all the windows have condensation on summer and winter. In dc bedroom mould is starting to come thought the paint and it's in the inbuilt cupboards in hallway. I have my windows open every day I have little heaters on as extras due to having crap storage heaters. I don't have any advice apart from I know it's so shit having a mouldy home

The floor's concrete, the carpet is so thin and threadbare you can see the concrete through all the holes. So there isn't really much point in turning hte carpet back to sniff I don't think

I'm banned from doing zumba now as DH says I've worn the carpet out!

There's no odd/damp smell that I've noticed.

I have the fan on while I'm cooking and in the bathroom I leave it on for 5 mins after I've finished.

In response to tricot saying mould/staining at the bottom of the walls means damp - not necessarily. We had this in our kitchen, but once we had the fan installed the condensation mould disappeared.

My dad was saying that when these old houses were built they had an airbrick at the top of the room for ventilation. That, combined with the drafty sash windows!

In need of brandy, bleach doesn't always kill the mould. Go to a good decorating store and get anti fungicidal wash for the walls. It is not massively expensive ( no more than a tenner) it kills the spores and helps prevent the mould coming back.
I have to say condensation is not always due to leaks, in our house we never had a problem until we had a new roof with lots of insulation in the loft and new windows. We have created a draft free house that is better heating wise, but because we don't have any draughts there isn't the air flow there used to be, when we had droughty old windows we never had a problem. We have spent a fortune investigating what could be causing it and there is no water coming in.

We never used to get condensation in our 1940s terrace, until we had our ancient back boiler replaced with a combi boiler in the kitchen. With the back boiler in, the core of the house (chimney breast) was warm, there was a constant flow of air and lots of mandatory draughty places. So the house was far from warm unless it was blasting away, but it was lovely and dry. The house is warmer without that airflow, but we do have terrible condensation on windows and outside walls, specially when people have been bathing or I've been cooking.

I just don't think older houses were designed not to be draughty.

Have you only started noticing the moisture since the weather got colder or is the moisture there all year round?

Oh thank you nancy will have a look next time I'm near a BnQ!

Just since it got colder.

Nancy, we've had a new roof!

Viva, I bet you did the same as us and put loads of loft insulation in too! It might keep the heat in but it must also keep the moist air from circulating. ( I know it works because our loft is freezing and when there was snow we were the last house in the street with it all still on the roof)

Yes we've got tonnes of insulation now. And we don't have massive holes in the slates anymore either.

Ouryve

Your old back boiler would also have given you lots of unintentional extra ventilation by sucking air up the chimney.