Cost to rebuild a 2.5 storey house

[Thenash 0]

I am looking to rebuild my landed property. Its currently a single storey house... i want to rebuild it to a 2.5 storey hse. Its 2000sqf in size.

Any idea on how much it would cost to so this.

[snoozee 98]

depending on how much build up area you are looking at and materials used, could be somewhere near the region of 900K and upwards

[Topline 1]

Hi

I'm thinking of doing something similar. Land size about 3000 sf with an old two storey house, which I would like to tear down and reconstruct a 2.5 storey house.

For 3000 sf of land, I think I can get about 1400 sf of built up for the ground floor. Does that mean I can build up to 1400 sf x 3 for the 2.5 storey or must the attic have lesser floor space? I would like to max out if possible.

How much would it cost to do this?

How much additional would it cost to add a basement?

 

[snoozee 98]

Basement will cost a few hundred k due to all the additional work like excavation, piling, etc. 

if your land is a inter terrace, you need to set back the house 7.5m from front boundary and 2m from the back. 2nd floor follow the same set backs. For attic, it is 3.5m front and rear from the building line. Meaning 11m from front boundary and 5.5m from rear. So the attic will have less internal floor space but area within the set back and open to sky can be used as balconies 

[Topline 1]

Thanks. I'm looking at a semi D. For the attic, I thought the new envelope guidelines from URA don't require the set back from building line anymore?

Haven't thought it through but thought it would be nice to have a basement car park... sounds expensive though.

 

[snoozee 98]

If semi-d, there is the 2m side setback as well. 

For envelope design, attic don't require an actual setback. But if you look at the regulation, the envelope for attic (based on 3.5m high attic) is based on a 45 degree line from the top corner of the floor below the attic. This is why I mentioned the attic setback is 3.5m front and rear based on this buildable envelope. So if you decide to have you attic height at just 3m, your attic front and rear setback will be 3m which is within the envelop. Technically you can have a staggered attic roof to maximize the buildable internal area. 

Depending on where the house is, if it's in a low lying area, the house will need to be build above a minimum platform level (MPL) of about 104mrl. So depending on how much the current ground level is below this MPL, you can do some excavation to build a basement as anything below the MPL would not be considered as an additional storey. But do note that for basements that have exposed sides (because of semi-d), the maximum allowed basement exposed level is 2.5m from basement finished floor level to 1st storey finished floor level. Unless your basement is fully covered on the rear and sides then you can have a higher inter storey level for basement. 

 

[Topline 1]

Thanks, you are very knowledgeable!

Why does it matter whether the current ground level is below or above the MPL? Even if the ground level is above the MPL, still can dig for basement?

Not quite sure what you mean on requirements for basements with exposed sides ... what is "maximum allowed basement exposed level"?  

[snoozee 98]

Whether the current ground level is above MPL or not is important as all first storey must be at MPL level. So if your land is below MPL, you need to raise the building up to meet the MPL for first storey. But if it's above MPL, you can just start building at current level. 

If above MPL, you can dig basement. But you may not be able to do basement garage. Again depends on your site constraints which only your architect can advise you when the topo survey is done. 

For semi-d, the side of the house is exposed. Normally this will be first storey. But if your basement is also exposed on the side that is not joining the neighbor, then it is limited to 2.5m if not URA will consider it as a storey and not basement. Unless your basement is fully underground then the 2.5m limit won't be there. 

[snoozee 98]

Basement information from URA guidebook

[Thenash 0]

So whats the estimated cost to build up 2.5 storey.

[snoozee 98]

For semi-d I would say set aside at least 1m as budget

[Topline 1]

Hi

 

I hear you need to budget $400/ psf (based on built in area) for rebuilding a semi-d. Would this include tearing down the existing house? If not, how much does tearing down the house cost?

[snoozee 98]

2 hours ago, Topline said:

Hi

 

I hear you need to budget $400/ psf (based on built in area) for rebuilding a semi-d. Would this include tearing down the existing house? If not, how much does tearing down the house cost?

the actual demolition and disposal of existing house is cheap and should be just maybe 30 to 50k. problem is if the house is very old and has asbestos, then need to arrange for specialist to remove the asbestos first before the house can be demolished. I had to pay another 20k plus for asbestos removal.

Edited March 5, 2019 by snoozee

[Topline 1]

Thanks Snoozee! I have come across a house (semi D) before where, due to the slope on which the house sits, the back half of the house is one floor or half a floor higher than the front. I have some queries:

(1) Would it be possible to dig out the back half to level the slope so the entire first floor sits on the same level? Any idea how much this levelling would cost if I am reconstructing the whole house?

(2) This also  means the back neighbours and those at the side will be much higher (about one floor) than mine. Any potential issues likely with that? Scared of landslide .... since my back boundary wall would have to "hold up" the back neighbour's house...

[snoozee 98]

land excavation is generally not advised though URA does allow on a case by case basis. however you need to bear in mind that if you are going to level the ground, you WILL NEED to put in ERSS which can cost hundreds of thousands of dollars. so imagine paying hundreds of thousands to view walls everyday. since you mentioned the height of the back yard is almost 1 floor higher than the front, you will definitely not be allowed to level the ground since the maximum height allowed for retaining walls is 1m (1.5m depending on cases) for landed houses. so what you could possibly do is to level the ground until where the height is about 1.5m and build a 1.5m high retaining wall  to hold the soil at the back.

if the front road level is below 104mRL, then you could build a "basement" and then add on the rest of the house above the "basement". why "basement" is in quotes is because the "basement" is actually at the road level but since there is a regulation that all living areas must be at or above 104mRL, whatever is below 104mRL can be declared as a "basement". it's a bit funny that the "basement" is at road level but that's how the regulations go. then you can build the rest of your 2 storey or 3 storey above this "basement". so if the house is in a 3 storey zone, you can technically end up with a 5 storey house (3 storey with basement and attic).

just to be clear, whatever I mentioned does not reflect the relevant authorities views. since each piece of land is unique on it own, URA has it's own definitions on what can or cannot be done. Even a QP cannot guarantee that what is planned can be 100% approved by the authorities. also it is no use trying to take examples of nearby houses to argue unless these houses are constructed after the last major change in regulations on envelope design. Cos after the regulations on envelope design, anything that was approved before that may not be approved under the new regulations.