[gilford]

To cut a very long story short, we have had a lot of renovation done on our new house which includes a lot of plastering and a new concrete floor in the bathroom (for underfloor heating). I was never told to ventilate the house after carrying out this work

The last room to do was the bedroom and we replaced the furniture in there in June. When we moved the old stuff out there was some mould behind the units which a local damp man said was just condensation from all the work that has been done.

Since then I have had the windows open every day but now the cold weather has set in its not really a good idea.

I noticed on Monday that there was a small patch of black in the very bottom corner of the bedroom which is obviously the same issue so I have bleached it and been out and bought a decent humidifier

I have had it on since Monday evening and it is taking a good 2 litres a day out of the room

How long do I keep this going for before I can consider it "dried out"?

Will I have to do each individual room in turn even though there is no issues in them?

Any other info appreciated

Cheers

[Phil57]

Have the windows got 'built in' ventilation, if not you should install.
When using the dehumidifier in the bathroom remember that the water in the sink-bath plug holes and toilet is also being extracted into the dehumidifier.

[gilford]

Originally Posted by Phil57

Have the windows got 'built in' ventilation, if not you should install.
When using the dehumidifier in the bathroom remember that the water in the sink-bath plug holes and toilet is also being extracted into the dehumidifier.

I have double glazing, but no trickle vents. How do I install them?

I dont need to dehumidify the bathroom, just the bedroom as mentioned

[Phil57]

Very easy to install vents, you simply drill a line of holes in the frame and secure with screws, the vents over the line of holes, job done!!

[DOBLY]

Originally Posted by gilford

and bought a decent humidifier

I hope that you actually bought a dehumidifier - otherwise you will be adding to your problems

Does this bedroom wall with the new black patch border the outside, the bathroom or another (inside room)? If it borders the bathroom, there could be some residual moisture in the wall that is being soaked up from the concrete floor. If the wall is to the outside, there could be some water in the cavity between the bedroom wall and the outside. If this wall is internal, then there is clearly a lot of moisture in your house. Other explanations could be a leaking pipe, leaking roof, faulty flashing etc. Best to get someone who knows what they are doing with regard to mold to look into it. You shouldn't be having these sorts of problems with a fresh renovation. Mold is very bad for your health, long term.

Concrete floors can take an age to fully give up all their moisture.

Hope this helps.