extending on top of single leaf/skin garage

[zaccari]

hi to you all,im looking to extend above our single skin/leaf attached garage.
.how difficult is this?
average price i should expect?
my house is a typical 3 bed semi,and the garage is typical size
my garage is joined to my neighbours,so the option of knocking it down,isnt an option that i have unfortunatly.
i know its hard to give advice on something with out seeing it,but just wanted to know if building an inner wall,would be ok.
i understand that the existing garage walls foundations would have to be checked.
there are a few houses on my street that have had extensions and one that has had similar to the type that i want.
i would greatly appreciate any advice that anyone can give.
thanks

 

[DevilDamo]

There are a few ways in achieving it. You can either build an internal block wall off the existing foundations, or off new foundations if the existing are not present/adequate. Then you just build on top like you would a normal two storey extension. The other way can be to span steel beams around the perimeter from pier to pier. This would create a ring beam type situation where the new walls above can be built off. This method would require new/underpinning at the pier locations by way of pad foundations. You could also look at constructing the upper floor in a timber frame to reduce the weight imposed on the structure below.

To have an idea of costings, you would need drawings prepared and for a contractor to quote. The steel frame/ring beam scenario would also require input from a structural engineer. The existing foundations and structure would also need to be exposed as this can have a serious impact on the quote of the works.