New Roof = Major Humidity/Damp in House

[qwertyuiop1]

I'm at an absolute loss and so are my roofers and even a family member who, while doesn't live in the UK, builds houses (properly) for a living in a far harsher climate...

I had a new roof put on and it's caused chaos with humidity in the living space. Got rid of bitumen and replaced with breathable membrane, added a new dry ridge, dry verge etc. but kept the same cement tiles as was nothing wrong with them and only needed a few replaced.

As a result had major humidity issues. As per family member, found that I had solid soffits only. Had 11 vents put in for a 42 sq meter loft. Still issues. Did some more digging and found dry ridge wasn't open so was opened. Still issues. As per family member, found that current insulation (which is inadequate and needs replacing and a full redo - missing insulation in some spots as well which I'm not happy about and I'm sure isn't helping) is blocking some of the vents so pulled back in thr absence of any vent trays for now. I've still got issues though.

Roofer wants to put on over fascia vents so I've said yes. Nobody back home is familiar with these so have been hesitant. If this fails, what else can I do? I'm running a dehumidifier 24/7 as if I don't, then the humidity builds and I have damp clothes, sofa, bedding, etc. The house is clearly struggling with its exhale. It is not liveable. I don't have any trickle vents in the house and the only problem I had previously was condensation on the windows when it gets colder and fairly quickly heat loss (hence loft insulation redo was on the list to get sorted this year).

Thoughts? I'm at a loss and so is everyone I know. Roofer said they've had the odd issue but nothing like this and are trying to make it right.

 

[Alastairreid]

Multiple issues by the sounds of it.
Make sure bathroom/ shower rooms have mechanical extraction and of the proper size.
Tumble driers extracting externally ditto cooker hoods.
Drying washing indoors.
You need both high and low level ventilation in roof space.

 

[qwertyuiop1]

Yes am thinking multiple issues and have to find the new balance. The bathroom has mechanical extraction (into the loft and out the wall) and also keep windows open to ventilate in addition. No tumble drier but do dry clothes with my dehumidifier and fan in the winter. Cooker hood recently cleaned and use for everything. I have both high (dry ridge) and low (soffits and soon to be over fascia) ventilation but perhaps not enough??? What else could I be missing?

There are sections of my loft that has a large amount of insulation over old and possibly damaged insulation, other parts with less, other parts with just old and looks like damaged insulation, and other parts with none which I'm sure doesn't help. I'm not sure what the people before me were thinking but after seeing a bunch of other stuff they did, I don't ask anymore....I am just gathering quotes for the insulation to be fixed (removed and reinstalled properly with eaves vent trays).

 

[JohnD]

Do you have visible eaves gaps to give ventilation on at least two sides?

The other usual causes of loft damp are found in

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...

www.diynot.com

There are some modern eaves ventilation systems that seem good. This is one example, there are many. Most can be retrofitted to give a clear path.

Manthorpe Eaves Ventilation Pack (10,000mm2 ) - 6m Pack | Roofing Superstore®

Providing a cost-effective yet practical solution for your roof ventilation requirements, this Eaves Ventilation Pack from Manthorpe features a 6-metre run ...

www.roofingsuperstore.co.uk

 

[qwertyuiop1]

Yes I pulled back all current insulation as the eaves were initially blocked so have daylight now on both sides.

I've done or addressed almost all of what you mentioned in your link - there is potentially draughts and possible problems with sealing of any gaps in the actual ceiling/loft floor (no idea if this has been done and wouldn't surprise me if it hasn't) However!!!! None of that has changed in the house from prior the roof being done.

 

[JohnD]

Yes I pulled back all current insulation as the eaves were initially blocked so have daylight now on both sides.

In that case, there must be a source of water you have not found yet. If it is since the roof work, it might be a leak at a chimney or gable.

Do you have holes in the ceiling below, for example for downlighters?

Is the loft hatch kept closed?

Do any of the rooms have misty windows on cold mornings?

 

[qwertyuiop1]

Ohhh!!!!!! Didn't think about the chimney or gable tbh. I will check that and see if there is any damp/moisture.

I have 2 down lights but nothing changed there.

Loft hatch kept closed.

When I moved in, I had window condensation on windows when it got colder. My plan was to address this this year as I suspected it was the mucked up insulation in the loft. But long story short ended up needing new roof first so have done that. It feels to me like there is an interplay here that I'm missing but will defo check out the chimney and gable areas (opposite ends of the loft).

 

[JohnD]

You could fit fire hoods over the downlighters, especially if they are in the bathroom. Check the duct is not leaking. Gaps round the edges of ceilings, and holes for pipes and cables, can be blocked with fire foam (but not in contact with electrical parts)

Water vapour is lighter than air so rises up through a house. It does not move downwards as normal airflow is out through the eaves.

You might have a plumbing or radiator leak.

 

[qwertyuiop1]

My plan was to fit firehoods around the downlights in prep for the new insulation (currently nothing in that space which I know is not ideal but is on the "immediate to fix" list). Will also check the duct when I'm up there.

 

[RandomGrinch]

I had a new roof put on and it's caused chaos with humidity in the living space.

For clarity, do you have any condensation/damp issues in the loft?
I think John has taken it as issues with the humidity in the loft, rather than in the living rooms...

The other usual causes of loft damp are found in

If there are no issues with damp in the loft, then the issue with the downstairs rooms, must be from somewhere else.

 

[qwertyuiop1]

I've contacted my plumber as well. I suspect there are a lot of problems with what the people before me did but was managing in a very careful balance. But it's the new roof that has really sent the house out of whack. The humidity in the living space seems to just be hanging around whether upstairs or downstairs which makes me wonder if putting trickle vents in would be something that I need to do. I've also been looking at PIV systems (not that I have a whole lot more money that I can throw at the problem but it needs resolving to prevent even bigger and more expensive problems)

 

[qwertyuiop1]

For clarity, do you have any condensation/damp issues in the loft?
I think John has taken it as issues with the humidity in the loft, rather than in the living rooms...

If there are no issues with damp in the loft, then the issue with the downstairs rooms, must be from somewhere else.

There is a problem in the loft but it doesn't seem as bad as in the living space. As I said above the problems in the living space were manageable before the new roof. It is now unmanageable which has had me focusing on the roof/loft space, especially when it became incredibly stuffy and germy inside the house when it turned out that I didn't have any soffit vents.

 

[RandomGrinch]

I may be wrong, but the problem doesn't seem to be the replacement of the roof.
The loft space is a cool, unheated, ventilated space.
It should be treated as a separate sealed space from the house - unless there was a direct leak from the roof/chimney/flashings etc. the loft space humidity should have no baring on that of the rooms below.
Improving your roof, may have simply highlighted the existing issues from downstairs, that may have escaped notice before, due to poor sealing and insulation - this may not be the new roofs fault!

 

[JohnD]

Shut all the doors on a cold night and see which room has the wettest windows by morning.

Do you have a water meter?

Look outside at gutter, downpipes and overflows.

 

[qwertyuiop1]

I think you're onto something. I think plan of action is to still check the chimney and gable regardless. Still have the over fascia vents installed for more constant airflow in the loft (it's not *as* bad up there vs living area but still needs some addressing). Get the insulation and gap sealing sorted properly (in midst of trying to find someone) and in the meantime have to continue to live by dehumidifier and airing out by opening windows a crack if/when its cool and dry enough. If still an issue I'm seriously considering a PIV