Damp rafters in loft

Smithy99

We've been in our loft today. Some if the felt has dropped down and the rafters I can see underneath feel damp which I'm guessing isn't very good?  The opposite side of the roof looks perfect.  Unfortunately we can't see it from outside because there's an extension on this section (where the roof falls in the opposite direction) and due to the way ours and the surrounding houses are positioned we cant get a good view of it. Does that whole side of the roof need redoing?

fenwick458

those concrete tiles have a lifespan of about 50 years, it looks like someone has patched up the felt too?

Smithy99

I'm not sure if it was patched or not. There's an extension that side of the house and the extension roof has that white membrane too.

greatcrested

If the rafters are wet that's not good.  Either you've got slipped/cracked/missing tiles/slates, and/or th wind is blowong rain under the tiles and the collapsed felt means the water is just dripping onto the wood.

Impossible to say whether "that whole side of the roof need redoing" without inspecting it. It could just need a few tiles replacing for £100, or yes a new roof. Or something in between.

Get a reputable roofer to go up and take a look. Ask him to take photos while he's up there so you can see what and why he recommends whatever work it is he suggests.

If it IS a new re-roofing, then get another quote to compare. If he just suggests a few tiles for £100 then fine, tell him to go ahead.

The felt needs replacing if the roof tiles are replaced.

Smithy99

Thanks. All the rafters that side seem a bit damp but surely it can't all be leaking, or can it? There's no obvious signs of lots of water getting in so I did wonder if it's condensation related? The other side of the roof has the sun on it all day and looks perfect still. 

Ectophile

If you have a shallow pitched roof, the problem may be that the tiles aren't overlapped enough.  On a stormy day, the wind can blow the rain up between the tiles, and it then drips onto the woodwork.  The builders of my house skimped on tiles, and left too little overlap.

I ended up having a roofer strip all the tiles off and replace the battens that hold them on, along a new membrane to replace the old felt.  He bought in a couple of palettes of reclaimed tiles and re-laid the whole lot with more overlap than before.

Jeepers_Creepers

If the wetness is quite extensive on that side, covering lots of these batten and rafters, then it's very unlikely to be a leak coming through.

Ecto's thought that rain could be blown up and under the tiles in very wet and gusty weather (which we've had) is a possibility. In such an event, the felt would normally do its job as the secondary protection layer, but the felt is torn in a few places so cannot do this.

However, even if rain got blown up between these tiles once in a blue moon, it really shouldn't be an issue; provided there's adequate ventilation up there, the loft timbers should dry out very quickly and no long term damage should arise.

Soooo, is there enough ventilation? Hmmmmm... Who's been stuffing the eaves?

Smithy99

Thanks Jeepers that's really helpful. The insulation was like that when we moved in but I've read in the last few days it shouldn't be in the eaves. There's no ventilation in the soffits (or anywhere else it seems) so would it make much difference in that case? We put some lap vents in last year and it definitely feels a bit breezier up there now, but there's more of them one side of the loft than the other and I can't see into the extension roof to know what's going on there as I'm not brave enough to crawl across.  I have someone who deals with insulation and condensation and has links to a roofing company coming in to look this week, so I'm hoping they can make sure everything is as it should be moving forward and everything can then dry out? 

Jeepers_Creepers

I suspect a good air flow will sort it.

One side is dry, but as you say the sun hits this. That actually makes it worse for the cold side as the moisture removed from the sunny side hasn't actually left the loft space but is looking for other cold surfaces to condense out on - so double-whammy for the cold side!

With a modern tiled roof like yours, and which appears to be in good order, I personally wouldn't be too concerned about a lack of felt. I certainly wouldn't go to the expense of removing the tiles to re-felt unless there was a solid reason for doing so, and I can't think of one.

As long as a loft space is howling with a through-draught, very little harm will come to it. Even if rain does get blown in once every 6 months and wets the rafters and battens, it'll be dry again in a day and cause no long-term harm.

PROVIDED you have a good draught.

If the soffits have no vent grills, and if it's clear that - even after removing the insulation in the eaves there still isn't a solid draught - then fitting round vents is a breeze.

Could you come back with what the insulation folk suggest?

Smithy99

Thank you.  Yes absolutely. I'll let you know. 

Smithy99

Well the insulation bloke who said he would come this week hasn't been yet. I contacted a roofer too, to get a quote regarding ventilation. He hasn't looked inside but looked on google maps and suggested a minimum of 6 tile vents (for just under £500).