Wet roof and rafters in loft - should I worry.

Blab1

Hi. 

Just come back off holiday and noticed a wet patch on the ceiling. 

When I checked in the loft, I found the insulation was totally wet through where water had dripped down from the bathroom extraction vent in the roof. 

Upon further inspection I noticed we had drip marks on the roof lining and damp rafters. 

I guess it’s been slowly dripping for a while. 

The house is only 9 years old, so I’m surprised we have a roof leak. 

Is this normal to let so much water run down the lining? Will it cause rot on the wood? Bit concerned 🙁 

Ectophile

A bit of damp in a big storm is liveable.  Provided everything has a chance to thoroughly dry out again, then the rot won't set in.

But if it's becoming a regular thing, then the roof needs fixing before something starts to rot.

Mistral001

This is most likely to be condensation, caused by moist air coming from a leak in the the extrator fan pipe just below damp patch and not a leak in the roof.  I suggest you test the pipe for leaks by running the shower with the bathrrom door closed on a cold day and then check the vent pipe in the loft.

Leon_W

That vent looks totally unsuitable to me.  Surely, water is just going to run down the roof and into that vent as it's flush. Usually roof vents are a small stack with a cowl.

stuart45

Flush vent tiles should have a drainage system built into them, so shouldn't leak if installed properly. The cutting out of the membrane looks a bit rough.
It shouldn't be leaking, even in heavy rain. The best time to check is when it's hammering down. 

grumbler

It looks to me like the vent isn't at fault. Water is just leaking down on the top of the membrane until it reaches the hole for the vent. As simple as that.

The question is why there is no any  diversion around the hole (like e.g. for Velux windows) and  why water leaks to the membrane through the tiles.

Blab1

grumbler said:

It looks to me like the vent isn't at fault. Water is just leaking down on the top of the membrane until it reaches the hole for the vent. As simple as that.

The question is why there is no any  diversion around the hole (like e.g. for Velux windows) and  why water leaks to the membrane through the tiles.

 Thanks everyone for your replies. 

But this is what I was thinking. The vent is just where the water is dripping from, but not where the water is getting in. 

Enjoying all this rain. Not! 

stuart45

grumbler said:

It looks to me like the vent isn't at fault. Water is just leaking down on the top of the membrane until it reaches the hole for the vent. As simple as that.

The question is why there is no any  diversion around the hole (like e.g. for Velux windows) and  why water leaks to the membrane through the tiles.

Normally you cut a cross in the membrane with a Stanley, and fold the top piece over the batten and tack it to the back. This diverts any water round the sides. Some developers have been using cheaper imported tiles from abroad which tend to be porous in heavy rain. Can also be if they stretch the gauge and don't get enough headlap on the tiles.

cerebus

You could get someone to spray your roof with a hosepipe and then see if you have a leak however your roof looks in good shape from your pic no cracked tiles are apparent 

It could be a combination of very heavy rain and high winds have forced water up and over your tiles

You will have to keep an eye on it and see what happens