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Post by cernunnos on Jan 17, 2023 9:58:11 GMT 1
quote from original post: "it has only been empty for 7 weeks or so and the moisture on the walls was incredible, you could see stain drips on the newly painted walls in the hall, and some of the thinner plaster skim areas have bubbled,"
Warm air holds moisture, the air cools down , condensation is the result , simple physics
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mysty
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Post by mysty on Jan 17, 2023 12:16:29 GMT 1
The other issue you can have is if you are repairing the origional plaster if the old plaster sucks the water out to fast the new plaster will puff and fall off or crack.
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JohnnyD
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Mayenne (53) When Covid allows..........Which isn't very often these days........
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Post by JohnnyD on Jan 31, 2023 17:22:20 GMT 1
OK an update now we are back in the UK, VMC is on, Humidifier is remotely controlled from here and drains into the kitchen sink, I swiched it on and off a few times yesterday as humidity rose to 65% ish, it brings it down to 60 ish again, I turned it off when I woke at about 0300 this morning, then I checked about 0830 ish the morning.........85% so its been on all day, and its now down to around 59%
I will have an idea of how much electricity this uses tonight on the EDF account and a linky update, but I doubt I can afford to run it 24/7
The VMC seems to be doing very little, why does the humidity shoot up as soon as we leave the house, It probably didnt even have time to cool down very much, and still the humidity is high.
Is there anything else we can do to improve the situation?
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Post by annabellespapa on Jan 31, 2023 17:50:26 GMT 1
Are there any air bricks in the house that our blocked/sealed up ? Is there insulation covering the VMC that could stop it working properly, or is the de-humidifier emptying the U bend on your sink giving you a high reading or from somewhere else.
Edit-
As this has only happened since you painted, is the type of paint covering up the natural air flow of the house, plasterer/render breathing etc. Small thing, I leave the log burner doors slightly ajar to help with the airflow, plus we had a situation about 20 years ago with an expensive Godin wood burner where the glass cracked while we were not there, neighbours said to leave the doors open slightly to take care of expansion and contraction of the cast iron.
Oh the joys of foreign home ownership...
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Post by pcpa on Jan 31, 2023 21:44:16 GMT 1
What is measuring the humidity, how and where is it measuring it, why do you have faith in it and does it really matter what it says?
Airflow is what prevents problems even in high humidity situations, the VMC will be doing its job if you have not sealed up all the air entry points which will be very difficult in an old house.
I will give you an example, I left my treasured self built car outside sheltered in a Carcoon over a winter where there was lots of snow and rain, the humidity inside would have been no different to that outside but it had airflow.
In fact unbeknown to me when the foam filters were blown off of the fans in high winds or when the rain was blown by the prevailing winds water was entering, by spring the rear of the carcoon (it was on a slight slope) had a couple of inches of water in it, it would have been like a sauna on sunny days.
I had left a piece of freshly ground bare metal on the top of the scuttle as a witness to see how much corrosion any bare metal parts specifically the cylinder bores (open intake sidedraft carburettors) might have suffered, it was still as shiny and untarnished as when I had ground it and placed it there.
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Post by pcpa on Jan 31, 2023 21:51:26 GMT 1
The VMC seems to be doing very little, It is not there to reduce the taux d'humidité, you might as well say it isn't working because your car is not doing any more MPG. that is why I stopped using VMC's with humidistats, they would switch to the high speed on a humid day, a day where I could not sense a higher level, and would sometimes remain on the high speed for days on end, running faster did not stop more condensation, there was never any with it on the low speed but water would be dripping through the ceiling without it.
The high speed manually controlled is usefull for removing cooking or toilet smells, steam or smoke.
why does the humidity shoot up as soon as we leave the house Because the outside environment is humid, because you return to the UK before the weather gets bad, it has been raining for weeks on end. Your machine is likely measuring the humidity of the air drawn into its casing, it may reduce that but as soon as its switched off there are billions of cubic meters of humid air waiting to take its place.
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exile
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Massif Central
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Post by exile on Jan 31, 2023 22:06:09 GMT 1
In theory condensation only occurs when the humidity reaches 100%. Above 95% and you could certainly get localised condensation on cold spots.
Overnight, temperatures fall and humidity level rises even if the amount of water in the air remains unchanged. You are likely to hit peak humidity at this time of year 1-1.5 hours after sunrise (temperatures continue to fall before the sun's impact really kicks in) so around 8-9:30.
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Post by cernunnos on Feb 1, 2023 9:11:13 GMT 1
OK an update now we are back in the UK, VMC is on, Humidifier is remotely controlled from here and drains into the kitchen sink, I swiched it on and off a few times yesterday as humidity rose to 65% ish, it brings it down to 60 ish again, I turned it off when I woke at about 0300 this morning, then I checked about 0830 ish the morning.........85% so its been on all day, and its now down to around 59% I will have an idea of how much electricity this uses tonight on the EDF account and a linky update, but I doubt I can afford to run it 24/7 The VMC seems to be doing very little, why does the humidity shoot up as soon as we leave the house, It probably didnt even have time to cool down very much, and still the humidity is high. Is there anything else we can do to improve the situation? Better circulation of air in the house. If you have shutters that fit well , close them and if possible lock them , then leave the windows open . Open chimneys offer a good solution too, if I understand correctly your chimney is blocked up ?
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Post by annabellespapa on Feb 1, 2023 12:02:07 GMT 1
OK an update now we are back in the UK, VMC is on, Humidifier is remotely controlled from here and drains into the kitchen sink, I swiched it on and off a few times yesterday as humidity rose to 65% ish, it brings it down to 60 ish again, I turned it off when I woke at about 0300 this morning, then I checked about 0830 ish the morning.........85% so its been on all day, and its now down to around 59% We bought our dehumidifier before we had double glazing installed, all our windows had condensation in the winter, today only one door is not double glazed and condensation forms on the glass when we have heat in the house, it happens overnight, we can wipe it away and it is not a real issue as we love the door and it would cost a fortune to replace, I have even thought of making it triple glazed by adding a double glazed unit on the inside of the door for not a lot of money. Our house here in Worcestershire is now on its second round of double glazing having updated and improved on the original double glazing installed by Everest in the early 90's. We now get condensation on the insides of the windows sometimes, I put it down to all the draught proofing and loft insulation trapping moisture inside the house.
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Post by cernunnos on Feb 1, 2023 12:48:30 GMT 1
OK an update now we are back in the UK, VMC is on, Humidifier is remotely controlled from here and drains into the kitchen sink, I swiched it on and off a few times yesterday as humidity rose to 65% ish, it brings it down to 60 ish again, I turned it off when I woke at about 0300 this morning, then I checked about 0830 ish the morning.........85% so its been on all day, and its now down to around 59% We bought our dehumidifier before we had double glazing installed, all our windows had condensation in the winter, today only one door is not double glazed and condensation forms on the glass when we have heat in the house, it happens overnight, we can wipe it away and it is not a real issue as we love the door and it would cost a fortune to replace, I have even thought of making it triple glazed by adding a double glazed unit on the inside of the door for not a lot of money. Our house here in Worcestershire is now on its second round of double glazing having updated and improved on the original double glazing installed by Everest in the early 90's. We now get condensation on the insides of the windows sometimes, I put it down to all the draught proofing and loft insulation trapping moisture inside the house.Exactly right . I insulated the ceilings but not the roof space above the grenier . We have a stair that goes up the middle of the house and two chimneys that act as air ducts .
We have no problem with damp or condensation although 90% of our windows are double glazed.
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Post by robertarthur on Feb 1, 2023 17:08:06 GMT 1
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Post by annabellespapa on Feb 4, 2023 10:39:39 GMT 1
Thanks for posting that RA, some useful points.
JD, do you have any velux windows which could be left in the trickle vent position whilst you are not there ? No help if you are not there.
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