cold bridges how to minimize them?

[swimmydeepo]

I'm doing a loft conversion which involve using metal joist hangers (instead of the traditional joists laid onto the inner leave of a cavity wall) and I am about to fix the chipboard on top of the structure, but but I've realized that I have probably omitted some treatment for possible cold bridges from the end of the joists (the ends fixed on the joist hangers). In fact I want as well apply some internal insulation using Celotex boards fixed internally on the whole 4 walls including the loft space. Clearly I cannot apply such insulation behind the joist hangers therefore cold bridges are going to be an issue.

What can I do to eliminate/attenuate such cold bridges?

I am thinking of using some flexible insulation like Airtec (airbubbles plastic stuff similar to that used in packaging with aluminium layer on both sides) wrapped around the joist hangers and joist ends as well. Will it work? Or will it make thing even worse? Any suggestion appreciated.

Thanks

Alex

[dg]

I can't see how you will get a cold bridge from the inner leaf of a cavity wall. The cavity is the thermal break.

dg

[swimmydeepo]

Well, as you can see I am not to sure of the issue. In any case there is no insulation in the gap between the two leaves (that's why I need to install internal insulation) therefore the walls will be very cold in winter....the joist hanger is attached to them and "connected" to the warmer air indoor. Wouldn't this be a cause for condensation?

[dg]

As mentioned, the cavity is a thermal break which will prevent cold bridging. Don't confuse a cooler internal leaf with a cold bridge.

Yes the blockwork internal leaf may be cooler than the room, but it will present no problems with condensation

How are your existing first floor joists connected to the external walls - most likely in a similar way to this scenario and the same as the majority of houses in the UK.

dg

[John Rumm]

I think you are worrying about a non problem. The joists are already on the internal leaf of the cavity wall. Ultimately they will be under flooring, carpet etc and will not represent any more of a heat loss path than any other joist in your house.

Don't worry so much ;-)

[John Rumm]

I think you are worrying about a non problem. The joists are already on the internal leaf of the cavity wall. Ultimately they will be under flooring, carpet etc and will not represent any more of a heat loss path than any other joist in your house.

Don't worry so much ;-)