Draughts thru my dormer walls????

[beefster]

The high winds exposed a possible build fault in our house which we moved to last year.
We have a radiator under the window in our loft extension (dormer) with the pipes coming out of the wall. The pipes have a plastic cap around them but there is a cold draught coming out of the hole the pipes enter the wall thru. Given this is an external wall and should be insulated this seems very wrong to me? The floor of the bedroom also seems very cold?
Externally the tiles and felt on ply (i assume) all look in tact and weather proof.
Under the dormer there is a ground floor extension. The soffit on this extension has the usual vents. My theory that i wish to try out on you.... is,
The wind is blowing in thru the vents and above the kingspan board insulation in the ceiling of the ground floor extension. Then blows thru this space into the original house (where the joists have been tied in) and up into the insulation space in the walls and thus out of any holes.
Whilst i believe there should be an air gap above the insulation board in the ground floor extension this should not be open to the rest of the house surely?? Hope that makes sense so far....
Should there be a barrier of some kind to stop this airflow?? I was thinking of taking the floor up in this bedroom and filling the space where the ground floor extension ties into the house with expanding foam??

Any advice help would be much appreciated.

 

[beefster]

Had the floor up today and it is as i thought...... wind blowing through the extension roof space into the house! My idea is to spray expanding roam into the ceiling void of the extension where it ties into the house to seal it up. This would fill the gaps between each set of joists above the kingspan.

It would seem the only solution to me??

The house is a converted bungalow and the wind can blow right thru the middle of the house via the soffit vents, under the upstairs floor, into the adjacent roof space / original loft and out of the soffits vents at that end. Obviously causing massive heat loss at the same time!

Nice find!!!!!!!! Not!