De humidifiers

[boustred]

I have hired a de humidifier to find out how much water there is in my property due to reports of damp within the walls (1910 semi 3 bed).

I am doing 4 hour sessions in each room (dining room, living room and bedrooms). The de humidifier is extracting about 500mls to 1000mls per 4 hrs.

I have no visual signs of damp which i can use as a guide to see if the de humidifier is doing its job.

The question is... is this a lot? Or is this "normal" for any house?

 

[jeds]

How is the aspidistra looking?

 

[JohnD]

This is warm summer weather (with rain) so the air will naturally contain a lot of water, and I imagine you have doors and windows open. If so this will not give a realistic idea of the dampness of the house.

You will get a better idea in Winter, when you will tend to have the doors and windows tightly closed against draughts, so no new moisture-bearing air gets in. Due to the cold, the air outside the house will hold much less moisture.

Did the "dampness" issue arise in a house survey? what did it say?

If the house is damp, it is very often due to insufficient ventilation - old houses were built to have draughty floorboards, loose doors and windows, and coal fires sucking air up the chimney. They did not usually have hot baths and steamy showers creating moisture. Most of all, they did not have people washing their clothes every day and hanging them over radiators which is a terrible source of damp, like throwing a bucket of water at the walls every day.

If you have a "building" damp problem, it is most likely either due to rainwater penetrating the walls or roof, or damp soil banked against the walls.

 

[harvestmoon]

I use a de-humidifer to dry my washing in a spare room (1900 3 bed terrace) - it is always left on Auto mode where it turns on above 60% humidity. It is lucky to get a litre a week if I don't do any washing.

 

[Panmure]

One of my rooms was feeling a bit damp - I put the dehumidifier on full and left it on over night (windows and doors shut, room approx 30m cubed).

It pulled out 4-5 litres a night for the first couple of nights, then dropped to 1L after about 4 nights.