New Roof = Major Humidity/Damp in House

[qwertyuiop1]

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.

Good shout. It's supposed to get cold and I'm off to my partners on Friday night so won't need to run the dehumidifier at night to keep me comfy.

I don't have a water meter and it's not possible to install one with how the kitchen was installed by previous owners.

Checked gutters, downpipes and overflows already and all good there. This actually all started by the major storms about a month ago that took down a large section of my gutter. Roofers found significant rot while capping over my fascia and fitting new gutters which made me decide to fix the entire roof (it was sagging a bit so knew it would need fixing at some point).

 

[datarebal]

are the cavities filled ? if you have cavities

 

[qwertyuiop1]

Yes. Previous owners had the cavities filled and has crossed my mind that this may also be contributing.

 

[noseall]

I think you're onto something.

Are you sure there is not a roofer-neglected fan from say a shower room or some such, that previously vented through the roof, but is now venting into the roof space?

 

[qwertyuiop1]

That's on my checklist for tomorrow. I got home a bit late today to have a look

 

[foxhole]

Drying washing indoors creates huge amounts of humidity far quicker than a dehumidifier can cope with.

 

[qwertyuiop1]

Mine deals with it fine. I confine the space close the door and dont stop until everything is bone dry otherwise I have no way to dry my clothes. That isn't the issue though. My habits haven't changed and I haven't had any issues until now with my most recent reno changes. Any issues with condensation that I have had have been managed.

After leaving some windows open just a tiny trickle I'm thinking another post may be right in that there's always been an issue with breathability of the house but the changes to the roof has just highlighted those issues for some reason (why? Not sure). I'm wondering if it's worth considering:

1) retrofitting trickle vents to windows (currently none)
2) installing a PIV system (I think these need trickle vents)
3) installing a decentralized MVHR system

I will be seeking out some roofing supply stores today to see if I can get some eaves vent trays to install and shove the insulation back down because that won't be helping by potentially creating some cold gaps. Will also be checking for any leaks and ducting from the bathroom.

 

[Murdochcat]

Have the residents changed recently?

Occupant habits have a lot do do with these issues

 

[qwertyuiop1]

Literally not one thing had changed apart from the roof.

I did have a gander around the loft this morning. RH is at 54% in the loft which isn't bad but isn't great. Ducting is fine. No water or damp issues from the gable end nor chimney.

Chasing roofers to fix a membrane they damaged while also trying to figure this out and to fit the over fascia vents but not having any luck in locking them down as to when they can come.

I'm planning on making some stops at some roofing supply stores later today to see if I can get some eaves vent trays to try and push what insulation I do have, more into the eaves while maintaining a gap for the soffit vents. I think I may have made things slightly worse when I pulled what is there back and pulled it back too far (whoops).

 

[Murdochcat]

All lofts need decent airflow - so don't even try to push the insulation back near the eaves - more the opposite - and then leave taking tests for a couple of weeks because any trapped moisture needs to allowed to dry out / leave.

As for the rest of the house - how do you dry clothes? does the bathroom have a decent extractor fan ? does the kitchen have an externally venting cooker hood?

 

[RandomGrinch]

I did have a gander around the loft this morning. RH is at 54% in the loft which isn't bad but isn't great.

The relative humidity of a correctly ventilated loft space should be similar to that of the outside air.

If an RH of 54% in the loft isn't great, what is the RH you are aiming for in the living space, and what is it currently?

I'm planning on making some stops at some roofing supply stores later today to see if I can get some eaves vent trays

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[pcaouolte]

What is wrong with 54% RH in the loft? It is an unheated, ventilated space. Humidity levels will be similar to outside if the ventilation is adequate and the temperature is similar to outside. RH here is currently 63% outside, overnight when the sun is not heating the loft space the RH in the loft will increase until it closely matches the RH outside.

 

[robinbanks]

I'm seriously considering a PIV

MVHR would be better..

..but I feel like there is some detail missing as to how you're assessing this excess humidity? Using a meter? Looking at condensation on windows? What temperature do you keep your house at?

 

[JohnD]

Of course, the water will be coming from somewhere. A house does not create water.

 

[Koolpc]

PIV would be a good thing to look into. I have heard of it doing a superb job at tackling similar issues to yours.

Obviously you are producing humidity from somewhere. That needs investigating. You havent got a load of people living in the house?