I want to build an extension above my existing double garage which was built
in the 1930s.
The current building is made of 9" solid brick wall on all 4 sides, with a
twin ridge roof with central valley.
I want to remove the existing roof, build 6 to 7 feet of additional brick
courses and then finish with a single ridge new roof (resuing the existing
tiles where possible).
My preferency would be to build the additional courses as a cavity wall but
I've heard conflicting advice from two building surveyors, one saying that
this is possible and the other saying that it would not pass building
Another option I have been given is to build the courses as solid 9" with
the addition of vertically hung tiles on the outside. This option is not as
aesthetically attractive because none of the existing main house has any
vertical tiling, it is all plain brickwork. There is a 10 foot alley way
between the existing house and existing double garage.
A third option is to build solid 9" courses and to then waterproof on the
inside with a membrane and appropriate insulation board. However I am even
less keen on this option and again one of the surveyors said that this would
not pass building regulations.
I want to create a bedroom and an office in the proposed new storey above
Does anyone have any comments - particular about the option of building
cavity wall coursework above the existing coursework?