Hi Anni,
There are several reasons why balk at garage conversions.
First, the vast majority of garages don't comply with current rules and regulations for habitable areas. The floor to ceiling height is typically less than 2.4m (especially when you take into account linings\floor coverings etc), the slab was built without a water-proof membrane and further more the slab wasn't designed for the purposes of supporting additional internal walls\structure.
I know in your message you state the opposite however if you do not have the paperwork, approvals to support your statements then you will struggle to find an engineer to certify the slab is compliant.
The second reason is that most people who call for a garage conversion is thinking given the structure is there the cost for conversion should only cost 20-30k max. Surely, how much can a few walls gyprock and tinkering around the edges cost.
The reality is much different. The walls cannot be lined directly as condensation will go through the brick and destroy your internal linings, this means you need to create an internal frame, you will need a top up to concrete slab in order for an engineer to sign-off, you will need to cut the existing slab to run services, line the roofing possibly remove the roof structure to raise, then reconfigure entries and required windows etc etc.
Further more there is additional cost in management, planning and coordination as much more thought and consideration is required.
Lastly, to get answers for all the above this typically involves a lot of mucking around, site visits and (unpaid) work for builders. In short given the amount of work available especially right now, from a business perspective most builder would just prefer not to take on the hassle.
Suggestion: If you are hell bent on conversion versus demo\rebuild then I recommend, getting an engineer to certify the slab and structure. An architect to do a design. Have a hydraulics engineer design the plumbing & drainage\storm-water have all these consultants provide reports you submit to a certifier to review and take to approval (typically CDC). Once you have approval (subject to insurances) then you will have much more interested builders as all the mucking around has been sorted and they have plans to quote and build from.
Hope this helps answer why builders shy away from these types of builds.
Below is a link to some photos of a garage conversion we have done,
https://www.facebook.com/media/set/?set=a.393814844030192.95152.281067805304897&type=3
Looking for recommendations for a builder experienced in the conversion of a solid double garage/bathroom to a granny flat. Local builders are baulking at using the appropriate legislation (or want to charge a fortune).
The garage has a concrete floor (set on piers), pitched tile roof with appropriate ceiling height (ceiling already in place) and an attached bathroom. We need to have it lined, the two roller doors replaced with something suitable and a straight, small line kitchenette installed.
It is for a relative, so we don't need separate electricity/water meter etc.
Located in the lower north shore/northern beaches of Sydney. Thanks, Anni
