Another loft condensation topic..with a difference

[pbyron]

Ok. I've read all the good advice on here already, but my situation is slightly different.

I have condensation in the loft, I've had it for 2 years now. At first we called in the original builder who first said we shouldn't be storing anything in the loft then cut the inside with a knife. I'm convinced this is not very professional.

Anyway, we have had new air vents fitted and I've checked the eves are clear of insulation. It's cold in the loft and I can tell the air is getting around.

A couple of other things may be important:
1) I boarded parts of the loft, leaving a big gap all around the sides.
2) Our walls have also had a damp problem ever since we moved in 8 years ago (and the builders refuse to acknowledge it).

I'm getting a bit desperate now, not even sure who I could call on professionally.

 

[JohnD]

is there a good airflow through your loft, in one side and out the other

How big are the vents

is the condensation on the felt

does it drip

do you have downlighters or pipes making holes in the ceilings allowing warm moist air to rise up there

is the loft hatch well-sealed

If you sit in the loft on a cold night with teh hatch closed can you see steam or mist rising up from the house anywhere

do you have water tanks in the loft. Are they cold and do they have close-fitting lids

do you always use an extractor fan in your bathroom and shower room until the steam is all removed

do you drape wet washing about the house

do you get condensation on windows or walls

 

[pbyron]

is there a good airflow through your loft, in one side and out the other.
Seems to be.

How big are the vents
the whole of the front and back of the house lengthwise and I can't remember width, but they should be big enough

is the condensation on the felt
Yes

does it drip
Yes, a lot


do you have downlighters or pipes making holes in the ceilings allowing warm moist air to rise up there
Nope

is the loft hatch well-sealed
Yes


If you sit in the loft on a cold night with teh hatch closed can you see steam or mist rising up from the house anywhere
No.

do you have water tanks in the loft. Are they cold and do they have close-fitting lids
No, we have a combi boiler.


do you always use an extractor fan in your bathroom and shower room until the steam is all removed
No, which might be one of the causes I guess.


do you drape wet washing about the house
Occassionally, but always with a nearby window open.


do you get condensation on windows or walls
Windows no (most of the time). Walls, yes, big time. We have mould and damp on the walls.

 

[JohnD]

start by dealing with the excessive moisture load in your house which is causing condensation.

The two most common causes in a modern house are:

- Not using extractors in bathrooms

- draping wet washing about the house

If you do these two things the house will always be damp.

Once you stop it will probably be cured, but increasing the ventilation will also help (but not if you don't correct those two things)

More info in http://www.diynot.com/wiki/building:condensation_in_houses

 

[^woody^]

From the details posted, then it seems that its one (or more) of three main issues ...

moisture is evaporating from this damp wall raising the loft humidity

heat is rising through inadequate insulation on the ceiling and condensing on the felt

moisture produced in the rooms below is getting through the ceiling, and raising loft humidity

Ventilation alone will not solve condensation problems - it's a case of balancing temperature, humidity and ventilation within the loft

 

[Deluks]

2) Our walls have also had a damp problem ever since we moved in 8 years ago (and the builders refuse to acknowledge it).

Whereabouts on the wall? Are your gutters installed incorrectly/leaking?

 

[JohnD]

heat is rising through inadequate insulation on the ceiling and condensing on the felt

I don't think you meant to say that heat condenses and turns into water?

 

[JohnD]

Does this help?

http://www.diynot.com/forums/viewtopic.php?p=1080717#1080717

Comments please

 

[Deluks]

Does this help?

http://www.diynot.com/forums/viewtopic.php?p=1080717#1080717

Comments please

Yes, Good job.

 

[pbyron]

Thanks for all the good advice.

It'll be tough to balance the humidity. With 2 small kids we always have a ton of washing and no chance of getting a conservatory built (not enough land behind house) so we have no choice but to dry clothes indoors in the winter.

We do, however, have a large dehumidifier now, so I'll try having that on each day to take some of the damp out of the equation.

Using the extractor fan in the Bathroom still seems to give us some condensation on the window, so I'm not sure how well that works, but it'll probably cut down a bit on the damp going to the loft.

I'm surprised that no-one has come up with a way of building houses without these problems yet. Surely everyone must dry some clothes indoors at some point, a tumbledryer is too expensive and seems to give off as much moisture anyway. I have seen some machines you can fit in the loft which move air around better, but they cost around £600 and I'm not convinced that they'd work anyway.

 

[davebwithane]

I moved into my house a year ago and the first thing I did was put in a decent shower. It caused the ceiling to go mouldy in all of the upstairs rooms. I have since put in an inline extractor fan and that seems to have solved the problem. I put in the biggest fan I could find which is a 350 inline extraxtor from tlc-direct.co.uk. I still get condensation on the windows, but I don't think the fans actually suck water off the windows. I might be wrong ... don't expect too much from your extractor fan. We also have a dehumidifier which fills up every day !