Over Facia Vents letting in too much air in a windy location

[boo60]

Hi all and thanks in advance for any help you can give me.

We bought a new build 2 years ago and since then we have had problems with part of the upstairs being very cold when the wind is blowing towards the front of the house. This effects a bathroom, two bedrooms and a storage cupboard. All upstairs and located at the front of the house. These are all connected by one length of UPV soffit with built in black over facia vents.

For example, on a breezy or windy day the temperature in the bathroom is about 4 degrees lower than the landing or the bedrooms/bathroom at the back of the house. There is no loft at the property as the builder had built into the roof area. There was a gap in the door surround of the ensuite and I could feel a significant amount of cold air coming into the bathroom through the gap on windy days. I have sealed it, but the room is still very cold when its windy and the floor especially so. I have recorded the temperature as low as 16 degrees in the bathroom when the landing is showing 20 degrees and the thermal images taken by the surveyor showed the cupboard to be as low as 11 degrees on a day when the outside temperature was 11-12 degrees suggesting little or no insulation.

We arranged a survey and the report suggested that as well as investigating some gaps in the stonework, the builder should also remove and investigate the soffit vents. The builder is adamant that cold air has to circulate around the void of the bathroom and there is no alternative as to stop it would cause condensation. My view is that as per the attached diagram, surely the air should only go across the roof to stop the battens rotting etc and if indeed it has to go into the void behind the bathroom walls then presumably as we are in a windy location, then the vents are allowing too much cold air into the property. The same happens in a storage cupboard on the same side of the house. I have added the Blue arrow to illustrate where the cold air is coming into the bathroom by the door surround.

The builder has just built more houses on the same road but seems to have used different soffit vents. I wonder if they recognise that as we are on the coast then the vents need to be less open etc.

Any thoughts on this would be greatly appreciated.

 

[Mr Chibs]

Is the ceiling vaulted in the bathroom or does it have a flat part?

Wind/air does need to travel like the arrow on your illustration to prevent condensation/damp, but shouldn't be getting through the insulation behind the ceiling.
Do you have downlights in the ceiling? Are they draughty?

Do you know what the insulation is behind the ceiling? i.e rockwool or PIR (kingspan)?

Sounds to me like like the insulation is non existant or perhaps poorly fitted.

Perhaps you could have the OFV's replaced with a ventilated soffit... but if insulation is the cause of the problems, this won't cure it.

 

[datarebal]

Your problem is insulation.
Not ventilation

 

[boo60]

Thank you both for the prompt replies.

Yes it is a vaulted ceiling with a Velux window fitted. I have no idea what insulation is fitted but I will try and find out. I did think it was strange that air was getting into the void. The strange thing is on cold days with no wind, or where it is blowing from a different direction, i.e. not at the front of the house, the temperature in the bathroom is stable. So I guess there is some insulation present, but perhaps the area below the vaulted ceiling is not sealed and therefore the wind gets into the walls?

I have added a picture of the ceiling and where the cold air can be found by the top of the door surround.

I have not checked the downlights but will next time. We did have the ceiling fan replaced as that was allowing cold air in but that has its own inlet so I guess that is not an issue. There was cold air coming in via the inset bathroom cabinet and toilet flush but I sealed both of these.

I just don't understand why cold air is getting into the wall void if it is sealed properly. The builder has commented without this cold air you would get condensation and mould in the walls which seems nonsense to me. If that was the case the whole house would be cold as the same would presumably be happening everywhere. They also claim the air test would have picked this up but I cannot see why as its one small gap in one room and the air only comes in when its windy. Also its not the air coming in that causes the temperature drop, its the cold in the walls and floor as I have tape across the gap in the door surround.

Thanks again for any responses.

 

[Mr Chibs]

I'm guessing, but if it's coming from the door architrave, then presuming it's a stud wall. Again either no insulation or gaps.

Pull the light out, there are spring clips that will be keeping it in, you might be able to see in the hole what's going on, or feed up your phone, and take some photos.

 

[boo60]

Just checked the light fitting by removing it and there is no insulation in the ceiling and you can feel cold air in there. I have ordered a camera extension for my iPhone so I can feed it into the hole and see what is going on. Seems very strange that there is no insulation. When you tap the ceiling in the bathroom it sounds hollow whereas the other ceilings that are also upstairs don't? Hopefully I will be able to film this tomorrow. Thanks again.

 

[datarebal]

Air flow is good and important .
But you should have done insulation there too