Want to purchase an old single storey inter terrace but am unsure about reasonable AnA or Rebuilding costs.

Background:

Land Size:approx 3k sqft

Build up: approx 1.8k sqft

Have the following questions:

1) Possible build on top of old structure to 2/3 stories? (heard that additional support columns will have to be built to support weight of 2nd or even 3rd story.) (is it safe?) (will there be so many columns in the house that it would be very obstructing)

2) How much it would  cost approximately if build on top of old structure to 2/3 stories?

3) How much to demolish and then rebuild the whole structure to a build up of 2000-3000 sqft?

4) Any good companies/contractors/lobangs to recommend?

Please help to advice! Any help would be appreciated! Need this information to factor in the cost of reno to make sure everything fits within the budget.

Would definitely prefer to be able to to add another storey or two without rebuilding to try and stick to the budget if possible!

THANKS IN ADVANCE GUYS

hardly anyone will use existing single storey house and rebuilt into 2/3 storey house. easier to just tear down and rebuild from scratch

whether can build into 2.5 or 3.5 storey depends on where your house is located.

cost wise depends on how much build up GFA you are looking at, soil conditions and whether there is a public sewer running through your house or not

assuming you want a build up area of 3000sqf, at an average rate of $300psf construction cost, this will cost about $900k.

if the land is on poor soil conditions, another few tens of thousands will go into piling.

if you are "lucky" to have sewer running through your house and you wish to build your house over this sewer, you will need to build an RC trench to protect the sewer. if not you will have to set back your house from the sewer line.

so all in, you are looking at a cost of about 1Mil thereabouts. note that this 1Mil is NOT inclusive of the consultants fees and authority fees for submissions.