Condensation in attic..again

elchanco

Last xmas i discovered we had a condensation problem in our attic (north facing side only).. I made sure insulation is not blocking vents & I even installed two vent slates in the north side of the roof... no improvement?

Should I put in more vents?? Any experience or help appreciated... really want to fix this problem before the structure of the roof gets damaged.

10-10-20

1. Find the source.
2. Remove or treat the source.
3. Treat the damage.

Where specifically is the moisture? (Rafters, windows, carpentry, floor, sarking?)

Do you have exposed/open water tanks in the attic or a leak in the rafters? Even a burst extractor tubing?
Do the bathrooms have adequate ventilation? Do you have a build-up of moisture in the rooms below?
Do you have vents in the windows/walls? Are these open or closed?
Do you grow 'plants' in the attic?
How is the attic insulated? (rafter level, joist level, none...)

Can you see all of the rafters and examine them for damp? Use newspaper to catch and show drips.
Where does the moisture occur? Is it confined to any one part of the attic?
It is above any one room or near an attic window?

Is the moisture doing damage where it's visible?

elchanco

Where specifically is the moisture? (Rafters, windows, carpentry, floor, sarking?) moisture is on the felt,only on the north side of the roof.

Do you have exposed/open water tanks in the attic or a leak in the rafters? Even a burst extractor tubing? main tank is sealed but a small adjacent tank is open

Do the bathrooms have adequate ventilation? Do you have a build-up of moisture in the rooms below? main bathroom has a window & vents. en-suite has a extractor fan which ive ensured is connected correctly.

Do you have vents in the windows/walls? Are these open or closed? vents in windows,open. no vents in walls.. i think

Do you grow 'plants' in the attic? No.. unfortunately

How is the attic insulated? (rafter level, joist level, none...) insulation is loose and spread across the floor of the attic, ive ensured that the vents are'nt blocked

Can you see all of the rafters and examine them for damp? Use newspaper to catch and show drips. rafters are damp (on the north side only) and some mould in corners

Where does the moisture occur? Is it confined to any one part of the attic? On the felt.. only one side of the attic..north

It is above any one room or near an attic window? above our bedroom & ensuite
Is the moisture doing damage where it's visible? yes


any help or advice is much appreciated...
cheers

10-10-20

OK, so it sounds like the condensation is a 'natural' product of the living spaces below and you may not have sufficient ventalation to eliminate it in the rooms. Hence, it's getting up into the attic through the various holes and through the plasterboard.

As an aside - do you have downlighters in many rooms under the attic?

Some more questions:
Do you have excessive condensation on the upstairs windows at this time of year?
Are the window vents free of dust/lint?
If you look at the soffits from outside, do you see vents regularly spaced, or are they 'inline' with the ?
Are there soffit vents on all sides of the house?

If it's a situation where there are no soffit vents, you're not getting any draw or cross-flow of air in the attic. Hence, your new tile vents are non-functional.

Have a look at this for an example of how it shoud be done at a soffit level:
http://www.insulation.kingspan.com/uk/pdf/k7.pdf

Page 11 shows how the insulation and ventalation work together with a standard (non-breathable) sarking felt to eliminate what you are experiencing.
If you have a situation where you don't have that cross-flow, you'll end up with rotten beams.

elchanco

As an aside - do you have downlighters in many rooms under the attic? downlighters (standard lights) 6 lights, 3 bedrooms,2 bathrooms,landing..

Some more questions:
Do you have excessive condensation on the upstairs windows at this time of year? yes, in our bedroom..

Are the window vents free of dust/lint? ill check this today..

If you look at the soffits from outside, do you see vents regularly spaced, or are they 'inline' with the ? soffits have vents but there not totaly covering all the soffits...

Are there soffit vents on all sides of the house? yes, except for a small section over the front door/small bedroom where this part extends out from the house..

If it's a situation where there are no soffit vents, you're not getting any draw or cross-flow of air in the attic. Hence, your new tile vents are non-functional. I agree, i want to find out how to get adequate flow of air..

Have a look at this for an example of how it shoud be done at a soffit level:
http://www.insulation.kingspan.com/uk/pdf/k7.pdf


I agree that i need more cross-flow in my attic but which way to go about achieving this is the question?
Is there professional's that specilaise in fixing this problem.?

Thanks again for your help..

wingknot

Hi Elchanco,
any time we came across a situation like yours on site (condensation in attic)the installation of two vent tiles front and rear mid to high center provided enough cross flow to eliminate the problem,any roofer can install these and would take no more than 20 minutes,but be careful who you choose,lots of cowboys out there.hope this helps.

JamesM

Is the water in the small tank hot when the heating is on ? Sometimes hot water can push up into this tank if the pump is too strong and cause condensation.
Jim.

elchanco

ive covered the small tank (must check if the water gets hot when heating is on). Ive also cleaned the vents in the windows...

cheers lads, keep suggestions coming

martin46585

just a note to ask if the felt is opened up at the high level vent, as it will look right on the outside though it will not draw air through the older type felts, and will not circulate air from soffit to ridge.
most of these vents are good for 10 to 15,000m2 in area so two vents may not be sufficience for the area

elchanco

i checked the smaller tank, no hot water.

the felt was slit open under the vents but i opened them more today to allow the warm air to leave the attic.

Im considering putting two more vents higher up in the roof, one on each side!