Cold New Bay Window

[Jasontenn]

Hi,

I have recently had new windows installed including two five panel bay windows. I watched the fitters install them and note that they used expanding foam in the exterior joints and in particular the bay joins.

However I am noticing that my living room seems colder than it used to be and that my older bay window seemed warmer. The new bay window is supposed to have argon gas and almost twice the thickness of the older one yet I feel a draught.

The issue is I cannot pin point the draught. I initially thought it was the trickle vent but this is not the case. I thought it was the joint between the frame and the wall but again no draught. I can feel a slight draught coming from the window but for the life of me cannot see or feel exactly where.

One thing I did notice is that on the internal bay support joins there was no expanding foam before the trim piece was clicked into place. Should this have had expanding foam and could this be the cause of my hidden draught. I did see them do the exterior join but they definitely did not do the interior ones.

I’ve added a picture of the interior before the trim piece was added.

 

[Wayners]

Get a thermal camera so you can see what's going on.
If you can feel a draft then you will have a visible gap or feel something with that amount of air moving.
What about the fireplace? Fires and chimneys.
Any chimney draw going on there?

Air circulation in the room is based on where the radiator (heat rises) is and where widows are (air falls as it cools).

Now you have insulated widows maybe the warm and cold air is circulated better and that's what you can feel.
You need to investigate further so you understand what's happening and work out if there is a problem

 

[robinbanks]

Smoke can help you visualise air movements that are tricky to feel

 

[Jasontenn]

Get a thermal camera so you can see what's going on.
If you can feel a draft then you will have a visible gap or feel something with that amount of air moving.
What about the fireplace? Fires and chimneys.
Any chimney draw going on there?

Air circulation in the room is based on where the radiator (heat rises) is and where widows are (air falls as it cools).

Now you have insulated widows maybe the warm and cold air is circulated better and that's what you can feel.
You need to investigate further so you understand what's happening and work out if there is a problem

There is a radiator directly under the bay window. The fireplace is on the adjacent wall but is blocked up apart from a small vent at the bottom.

I will try and do a smoke test to see if there is any noticeable leaks.

Should there be expanding foam in the bay supports under the plastic trim?

 

[Wayners]

No foam needed in bay windows required

 

[Jasontenn]

No foam needed in bay windows required

Thanks. Would you advise putting silicone around the edge of the trim. It’s hammered into place with a rubber mallet concocted in pretty tight but it could be that some cold air may be getting through at the edges.

I’ve added a picture of the bay pole with the trim attached.

 

[Koolpc]

No, don't put silicone there as you need to be able to access that area....

Figure out where the draft is coming from first before you do anything..

 

[Wayners]

If you wanted to get some low tac 90 day easy remove masking tape and cover joints in window.
Tesa yellow
Masq purple
That sort. Maybe a wide one...
Don't use the cheap same day production masking tape tape that everyone knows.
That will help you decide by blocking off all gaps making it airtight..