Roof felt leaking - but not ripped

[NickB_99]

Was up in the loft today getting the Christmas decorations down, and noticed I've had some areas of leaking from the roof.
From a more thorough inspection, it looks like it's actually happened in quite a few places, with small amounts of water coming through.
The strange thing is it looks like it's actually coming through the felt between the roof joists(?) and not at the joists or the joins where the felt is lapped. There are some quite large damp patches in the felt and I'm guessing these have leaked through the water.
There are some damp signs on the MDF boards in the loft, and it looks like where it has leaked, has come down in a line perpendicular to the joists - in line with the roof battens on the outside of the felt.

The house is about mid-60s, reaonably modern construction with concrete interlocking roof tiles.

I can send some pics if it will help.

As you can imagine I'm thrilled about this approaching Christmas - especially as I only moved in in May, and got nothing untoward back from the roof in the survey.

I'm assuming you don't normally get a lot of water coming down the felt and the tiles would normally take care of the majority of it?
Wondering if maybe previous tennants been stomping about on the roof with aerials etc and broken a lot of tiles? Or the ridge pointing can leake enough to cause this sort of problem?

I'm hoping it doesn't result in needing a new roof, so am interested in getting some background first before I try to get some diagnosis/quotes to see what my options may likely be.

Thanks for any help in advance!

 

[joe-90]

Is it condensation?

 

[NickB_99]

Is it condensation?

That did cross my mind, but I wasn't sure if it can generate that much in a loft? Is it a common problem ?
I guess most condensation upstairs would come from the bathroom - there don't seem to be any big gaps in the bathroom ceiling, four halogen spots, but seem reasonably well tight sealing with the ceiling. Loft hatch seems to fit quite snugly too.

 

[joe-90]

I've been in a loft that was absolutely drenched with condensation, everything I touched was soaking. I didn't believe it until I saw it.

 

[NickB_99]

I've been in a loft that was absolutely drenched with condensation, everything I touched was soaking. I didn't believe it until I saw it.

After your suggestion I had a quick search on the forum for condensation.
Upon reflection, this could fit the bill - what you say above reinforces it too.

The people before me had the bathroom upgraded. I'm guessing this is when the halogen spots went in. There is no extractor fan!

Think I probably need to take a look at ventilation, not sure what's in.
Any suggestions what's most effective?