Cause of condensation in loft, & best solution?

[cyphex85]

Hi all,

I have a mid 80's detached brick house with concrete tile pitched roof. I only have (shoddily cut) vent holes in the gable end leading to outside vent the soffits don't have vents. I noticed in attic recently during cold spell there was a lot of condensation and droplets were falling onto attic floor on the cold side which doesn't get much of the sun. Insulation in attic is only 200m and I don't have cavity wall insulation sinces it's wood bearing house. Another point to note is my loft hatch isn't insulated so I will get a new one installed in the new year.

I've called a few roofers and getting mixed messages on root cause and solution:
a) Needs re-felting due to webbing exposed that signs it's damaged through wear and tear + option c
b) Improve ventilation with 6 roof tile vents only
c) Improve ventilationwith 6 roof tile vents & circular soffit vents every 1M
d) Improve ventilation with 6 roof tile vents & overfacscia vents

If I opt for the ventilation route only I've read airflow design is key and the lower soffit/fascia vents used for intake should outnumber the exhaust roof tile vents. I'm also worried that the gable end vents might disrupt the airflow from low intake -> high exhaust if I were to get both roof tile vents and soffit/fascia vents. Based in North west UK.

My Questions are:
1) Is re-felt or ventilation the correct solution?
2) Would the gable end vents impact any of the above design options?
3) Which solution for condensation is optimal for my house ?

Many thanks

 

[datarebal]

Webbing exposed .. haha
Forget that one type 1f felt was like that when new .

Make sure you have good insulation , including loft hatch .
Make sure extractors vent to the outside
Any increase in ventilation will help . If you have a profiled tile simply opening up felt laps will help and cost nothing

 

[BlueLoo]

Bathroom Extract vent anywhere?
See recent posts on same

 

[cyphex85]

Webbing exposed .. haha
Forget that one type 1f felt was like that when new .

Make sure you have good insulation , including loft hatch .
Make sure extractors vent to the outside
Any increase in ventilation will help . If you have a profiled tile simply opening up felt laps will help and cost nothing

Thanks for reply
I wasn't sure as it's the older non-breathable stuff which I was told has a shelf live of 20 years so wasn't sure if i really did need a full re-felt job. Sounds like I should ignore the re-felt option.

I don't have extractor in bathroom yet (that's another job!) so I have recently put extra insulation over the bathroom ceiling only to stop vapour escaping through ceiling light holes.
When I do get one installed I will be using wall flu pipe rather than via roof.

I think I have profiled tile (Marley's double roman tiles)?
I've heard about the felt laps option on here using DIY wedges or buying plastic ones from shop.

Loft hatch and insulation across entrie attic are now on my job list - cheers

 

[cyphex85]

Bathroom Extract vent anywhere?
See recent posts on same

No but i suspect vapour some was escaping via the ceiling lights (see my reply above).

 

[Nige F]

Thanks for reply
I wasn't sure as it's the older non-breathable stuff which I was told has a shelf live of 20 years so wasn't sure if i really did need a full re-felt job. Sounds like I should ignore the re-felt option.

Ours has been up for 70 years and only@ the eaves have perished a bit

 

[cyphex85]

Thanks that's reasuring to know.
Sounds like I just need to decide on which ventilation is best suited for my property

 

[JohnD]

CONDENSATION IN LOFT (ANSWERS)

This seems to be the time of year for condensation in lofts, so instead of replying to lots of queries I though I would write this "one-size-fits-all" post. Please also see //www.diynot.com/wiki/Building%3ACondensation-in-Houses Condensation in lofts occurs when the amount of water...

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