cross wall construction with traditional extension?

Jemma01

Hi

I feel like I'm probably asking the wrong questions, but please bear with me. 

I've done level two survey and found this: 

The original part of the property is of cross wall construction.   

Notes: The main walls are of cavity construction and measure around 270mm in thickness where measurements were taken. Cavity walls usually consists of external brickwork, a gap of between 50mm - 100mm and internal blockwork. The cavity should be fully or partially filled with insulation. Metal bars connecting the inner and outer leaf. The extension is of traditional cavity construction.  

Few questions please:  

* Would this be a non standard construction?

* Does it help in any way that there is an extension of standard build?

* I'm really confused how they would be connected. Does that mean I now have a cavity wall in the middle between the extension the original rear timber studs?

The survey didn't highlight this as a problem but I don't want this to cause me issues later down the line.

Thanks

stuart45

I don't suppose you've got any photos of the property?

Jemma01

stuart45 said:

I don't suppose you've got any photos of the property?

I sure do from the surgery.

[Photos removed]

stuart45

The answers to your questions.
1) crosswall construction is known as Rat-Trad.(rationalized traditional,). It's neither traditional or non standard.
2) Don't think it matters. 
3) the extension walls connect to the cavity walls of the gable.wall and the central pier.
There were loads of different types of crosswall construction houses built in the 60's and 70's. The front and rear flank walls are probably timber frame.
Most crosswall houses have much larger windows than yours, especially upstairs. The weight of the upper floors and roof are taken by the gable and party walls to allow for this.

Jemma01

stuart45 said:

The answers to your questions.
1) crosswall construction is known as Rat-Trad.(rationalized traditional,). It's neither traditional or non standard.
2) Don't think it matters. 
3) the extension walls connect to the cavity walls of the gable.wall and the central pier.
There were loads of different types of crosswall construction houses built in the 60's and 70's. The front and rear flank walls are probably timber frame.
Most crosswall houses have much larger windows than yours, especially upstairs. The weight of the upper floors and roof are taken by the gable and party walls to allow for this.

Much appreciated, thank you

For 3, from what i understand you're saying (and sorry if it is wrong, not putting words in your mouth), there wouldn't be a cavity wall in the middle (previous rear of the building) as there wasn't one in the original build (original design is timber studs), and they would have attached the extension to the ends of the cavity walls (left and right ends) and extended it out to build the sides of the extension.

stuart45

That's what's probably been done. The cavity walls of the extension join on to the cavity walls of the house. It's possible to join a cavity wall to a stud wall, as the cavity walls join the studwork above. It's a weak spot in crosswall construction, as timber and masonry move differently. I expect your surveyor is well aware of any issues with crosswall construction houses.