Grp valley

[liam999uk]

Hi all.

We have just had a new roof fitted on our property. The roofer has put in fibreglass dry valleys but he has not fitted any membrane along the full length of the valley. Now I have been up in the loft and the underside of the valley has condensation on it.

Basically should he have put underlay underneath and should i get him back to do so? How long would the job take to do as it means removing the valley tiles and also the valley then re-lay it all. Could it be a problem with the heat escaping from the house? The roof has soffit vents and the membrane is now breathable.

Cheers again.

 

[Alastairreid]

Non breathable felt? does the roof have high level ventilation as well?

Its good practice to use a geotextile beneath valleys

 

[liam999uk]

Hi, the membrane is breathable across the house. Its been cold today and im not getting any real condensation issues anywhere else in the roof space that I can see. The grp dry valleys dont have any membrane underneath or support boards. Im getting condensation in the very peak of the valley. Now it doesnt seem to be dripping anywhere really just sort of staying there. But i thought the whole point was to put a membrane down the length of the valley to catch any condensation/water vapour etc.

Cheers again.

 

[liam999uk]

UPDATE AND PHOTOS. The roofer is apparently coming round to have a look at the valleys sometime before the scaffold comes down. Ill believe it when i see it.

Next problem is that we are getting some more bad condensation on one side of the house. It has been cold and frosty the underside of the tiles are frozen. The membrane is dry on the topside but wet underneath. I believe i need more soffit vents at that side as there are only around 5 in a 7m length.

Whats the best way to sort this? At present its wetter now than before the roof was done. Some of the membrane looks a bit tight in places, i dont doubt it wasnt an easy task installing it as it was bad weather when it was being installed. The insulation needs all replacing and making thicker its wet at present from the condensation and when the roof was being constructed which does not help. I believe the membrane is a bit crap too that has been used, TIL R breathable.

Thanks again

Untitled

• liam999uk
• 29 Dec 2014
• 1

Untitled

• liam999uk
• 29 Dec 2014
• 1

Untitled

• liam999uk
• 29 Dec 2014
• 1

Untitled

• liam999uk
• 29 Dec 2014
• 1

 

[Toproofer]

You need more insulation in loft space and the felt looks tat,the roof is one of the most important parts of house, so why use cheap felt on it!! Can never work that one out😤as for valley there needs to be valley boards on, i never use them plastic valleys but there should be some thing under there

 

[liam999uk]

You need more insulation in loft space and the felt looks tat,the roof is one of the most important parts of house, so why use cheap felt on it!! Can never work that one out😤as for valley there needs to be valley boards on, i never use them plastic valleys but there should be some thing under there

Honestly mate im at my wits end with it all. Ive literally just tried getting through to him again no answer. Looks like ive been taken for a mug. I know it's wrong i believe it should have support boards underneath and as for the membrane, dont get me wrong it does stop water getting in the loft but it doesnt seem that breathable to me. I think it needs over fascia vents and also a few vent tiles in too possibly as i believe now hes bodged the dry ridge too. Should never have paid him then the ball would have been in my court still...

Fancy doing it for me while the scaffolds still up???

 

[noseall]

Stop fretting about the brand of felt, your tiles are the primary weathering layer and some roofs have no felt at all.

However, the lack of felt at the valley and zero valley boards in not ideal.

 

[Toproofer]

Could be just hot air getting into loft space,so get the insulation upgraded,make sure loft hatch as king span on back of it, another thing you can do is take off dry ridge system and cut felt all along ridge to make a 10-20 mm gap then put dry ridge back on😉that should inprove the ventilation abit, but I would Deffo get some valley boards put in pal,was the guy the cheapest quote you had?or only quote?😁

 

[liam999uk]

I had 2 quotes at that price. We got quoted £4100. It ended up being £4300 with an extra skip and the new dry verges. Other roofers were quoting between £4500 and £5250. Moneys tight with just buying the place so i suppose i went with the cheapest quote which may not always be advisable.

Honestly i went up earlier and had a better look at the valleys. I can put my hand through between the membrane and batten that he has put the length of the valley and touch the outside of the grp valley. It is a shambles to say the least.

Anyway on a positive note i actually got in touch through to another roofer who i know (and should have used really)to sort the mess out so hopefully it will be sorted soon.

I deffo need the valleys doing right though they are not good enough.

I may ask the lad to sort the dry ridges too if hes up for doing it. Might as well have it right!

Never again!!! Cheers all for your help though!

 

[liam999uk]

Morning all.

I was just having a think of how the valley boards could be installed. If you see the photos there is a length of wood running down the length of the valleys. this is structural as the that part of the house was extended in the past. Now I thought valley boards had to go flush with the top of the rafters all the way down. That piece of wood is around 12mm thick and is sat on top of the rafters from the original house structure.

My question is how would the valley boards be installed now? I believe you can use a 6mm board on top of the rafters but could we use a deeper one?? Does it even matter thinking about it when the depth of the battens are 25mm??


cheers again.

 

[Owen74]

OK so I realise this post is ancient (2014) but is my same exact problem I have today ! Plastic roof valley exposed underside in loft, condensation all over it. No membrane covering it. No amount of ventilation helps - it's a 3mm bit of plastic with cold air outside and slightly less cold inside. It's going to get wet. If the original poster is still on this side can you please give an update on how it got sorted in the end? Thanks.