joining new wall to existing cavity wall

[sudbrooke]

I recently had an extension built onto the existing house (which has cavity walls). The builder simply butted up the new wall to the old, using ties that were screwed to the old wall and set into the mortor joionts of the new wall.

Now I am planning another extension and I got a different builder over to discuss. He sais you should always cut into the olf wall, through to the cavity, and make th ecavity of teh old and new wall continuous , other you get a cold point and damo can get through.

I see this maks sense, but do buiding regs. require it, and why did the previous builder not do it, or the building inspector require it?

 

[freddiemercurystwin]

I would recommend it if possible as there is no doubt that a cold bridge will occur if the skin is not cut, in my experience though, strangely, BC don't seem all that bothered. It also depends upon its location, if its right on the corner of the house for example you have to ask yourself if chopping a section of brickwork out of the wall is really such a good idea, having said that the new cavity wall is gonna be tied together so (in theory) no structural integrity of the structure will be lost.

 

[jeds]

Double post. Naughty boy.

 

[noseall]

There are situations where cutting will be a problem structurally particularly if the engineer is relying upon the existing returns for buttressing as is occurring on a job we are doing at present.

The cold bridge issue is negligible compared to the importance of structural stability.

 

[mikric]

There are situations where cutting will be a problem structurally particularly if the engineer is relying upon the existing returns for buttressing as is occurring on a job we are doing at present.

The cold bridge issue is negligible compared to the importance of structural stability.

Agree with above everytime

 

[rustyruss]

Still saw cut with dpc in