Advice on adding second storey

[fitz00 0]

Hi everyone! Been a long time reader, but first time posting on here.  

I just bought a 2500 sqft single storey detached house on a 4000 sqft piece of land. I have several quotes from builders to rebuild about $1.5m and 12-18 months for 2.5 storey. The other option would be to add a second storey over the existing structure. PE says micropiling required to strengthen foundation. Anyone know if the second option would be cheaper/quicker and have any good main cons to recommend. Really appreciate any advice thank you! 

[snoozee 98]

since it's a single storey, there's not much value to keep the existing house and do a reconstruction since there's nothing much you can reuse and you are still subjected to the constraints of the existing structure.

it is faster to demolish an entire house than to pick and choose what needs to be demolished. also with the house gone, it would be easier to do the foundation and soil prep including termite treatment.

1.5M for a 2.5 storey detached house sounds reasonable assuming is all in already.

[fitz00 0]

Thanks @snoozee. Yea I figured it would be easier. What about costs? Would adding a second storey be much cheaper than a rebuild? I assume it woulld

[snoozee 98]

Don’t think you can save much from a reconstruction vs a rebuilt. You need to put in new piles either way and there won’t be much cost difference. The cost of the actual building structure is maybe 15% to 20% of the entire project cost. So conserving the original 1st storey structure won’t save you much compared to if you are doing a reconstruction for an existing 2 storey house. 
let’s say you can save 50k from conserving the 1st storey. But the existing structures prevent you from the ideal design layout you have for the first storey. Would you spend this 50k to get your ideal house or save on it now but end up thinking “what if I had just spent that 50k initially“ in future

[petetherock 13]

Yeah

its likely to be rather old and you don’t want to save and end up with structural issues later on

[mamamiasimmy 0]

Think if its a 2 storey house can support ba. if existing 1 storey house dont think the existing structure can withstand without add new structures . some of my friend who purchased 1 level terrace house also chose to rebuild instead.

[fitz00 0]

Thanks all. I think now the issue is how to best save on costs. I proceeded with the purchase on the assumption that reno costs could be kept around $1.2m which is what my contractor originally quoted me when I brought him to see the property a while back. He has since increased the quote to $1.5-$1.8m and I may have to get a renovation loan for the difference, which is not ideal. So I'm trying to see how to keep costs low. 

[snoozee 98]

you are not going to save 300k on retaining the existing structure.

if you are lucky and your house is in a area where there is good soil, you may escape with just doing footings or a raft foundation. this could save you maybe close to 100k from doing piling.

to do fencing instead of build brick walls as boundary wall will mean quite a bit of savings as well.

opt for those mid-range or lower ranged sanitary ware. a $300 toilet bowl compared to a $1k toilet bowl means $700 savings. multiply that by say 6 toilets will mean about $4k in savings.

don't splurge on smart switches, etc. do normal ones which are non-designer stuff

opt for half height tiling for toilets unless necessary like in shower areas. you save on the cost of tiles and labour for tiling. but still need to pay for plastering and painting which is still cheaper than tiling.

for flooring, marble would be most expensive. getting big homogeneous tiles for living room will look good as well. if you like hard wood floor for rooms, get parquet instead of engineered wood. else just do tiling as well for the rooms.

light fixtures can order online from China. can save quite a substantial amount as well though you may need to pay the electrician to install them since your main-con can't earn from this. for ceiling fans, no need to buy those $400 and up DC fans when a $200 AC fan will perform the same job. unless you want to splurge $3k on a 84 inch Haiku fan to make your house look grand, else getting a few normal ceiling fans or standing fans will also work.

the ducting for ducted aircon will cost much more than the aircon unit itself. get ceiling cassette units to save on the cost.

if you can live with exposed beams on the ceilings, tell your main-con or PE that you do not want to have false ceilings and ask the PE to design flat beams instead. a normal beam will be about 500mm to 600mm thick whereas a flat beam will be about 300mm to 400mm thick. no false ceilings = $$$ saved

for the roof structure, can ask the PE to design using steel columns and beams instead of RC. then do a metal roof. this will cut the construction time as well as lower the cost a bit.

sliding windows are cheaper than casement windows. no need to pay extra for low emission glass as normal glass will work. if want to block out the sun, do solar films later on.

doing normal metal railings will be much cheaper than glass railings.

anyway, there's many things that can be done to cut costs. how much the house costs eventually really depends on how much you want to splurge on the finishes. by cutting down on the luxury finishes, you can save quite a bit of costs on the construction.

[mamamiasimmy 0]

nice piece of sharing from snoozee! really love your advice on this fourm! ^.^

[mamamiasimmy 0]

@fitz00 if your pe mentions that need piling foundation, probably you cant escape this cost. construction might get abit higher due to the covid 19 situation in singapore.

[snoozee 98]

29 minutes ago, mamamiasimmy said:

@fitz00 if your pe mentions that need piling foundation, probably you cant escape this cost. construction might get abit higher due to the covid 19 situation in singapore.

might not be the case. piling would be needed to create new support for the upper storeys since the existing foundation won't be able to support the new upper storeys when the first storey is retained. my thought is that the new piled foundation is solely only for the new storeys and not joined to the existing one (I may be wrong on this though) since there's no way to dig big enough holes in the ground for footings or do a raft foundation since the existing foundation is in the way.

but if the soil conditions are good enough and the house can be built on footings or raft foundation, then there's no need to do piling at all for a complete new built.

I think what TS should do now is to engage a PE, then get a soil investigation company in to perform the soil investigation for the land. then from there determine if piling would be required or not.

of cos if the house is located in a well known estate with low lying area with marine clay soil, then most likely need to do piling. but even then, within these type of estates, there are higher areas which have good soil which need not do piling at all. So paying 3k for the SI report is important before the start of the project planning.

[3Cube 9]

I use to post on this forum regularly but not any more. Why?

You have to understand this:

You can have Lego model after a buildings but building can't be based on Lego concept.

Adding storey is not like Lego where you simply just stack on. There will be consequences!!! Look at the various history of collapse locally & you should understand.

Take for example:

Imagine the human body to be a building. The feet is the foundation of the building. The bone & muscles of upper body are the beams & columns of a building & the skim is the brickwall etc.

Normal healthy body will be able to stand on their own feet. As the body put on more weigh (similar to building stacking more storey / floors), there will come a point in extreme cases where the too much body weigh is gain that the feet simply cannot support & cracks.

So think about this. Are you going to compromise the safety of the inhabitant to save money?

Besides, with the ever tightening local laws & regulations due to the various structural collapse, I strongly doubt any Professional Engineer in his / her right mind will risk their Professional License to design building Lego style to help the owner save money. Similar so for the licensed builders. No body in their right mind will risk this to secure a job.

Also, as a builder myself, I need all to understand this.

After every building is completed, The Architect, Professional Engineer, Licensed Builder, Licensed Electrician, Licensed Plumber, etc will need to endorse a form to submit for application of the TOP (Temporary Occupation Permit). This bounds the individual (Architect, Engineer, Builder, etc) for the duration of the building (until the building is demolished for another rebuild in the future) or the individual's LIFE, whichever is later!!

Hope everyone understand this & will be reasonable on cost expectation from now on.

Edited October 16, 2020 by 3Cube
addition

[3Cube 9]

I also forgot to highlight this.

When the old single storey building is retained & additional piling is needed. You have to understand it'll be more expensive for "Mobilization Cost". Which means some contractor, subject to site condition, might just add in cost of demolish & reinstate as the mobilization cost. If not, then you tell me how to move the piling rig (which looks like a mini tank) to the back or centre of the old building without damaging the old building??!! Please keep in mind most time there is no side or rear access to the site.

This is just a practical explanation to help all to understand.

[3Cube 9]

31 minutes ago, 3Cube said:

After every building is completed, The Architect, Professional Engineer, Licensed Builder, Licensed Electrician, Licensed Plumber, etc will need to endorse a form to submit for application of the TOP (Temporary Occupation Permit). This bounds the individual (Architect, Engineer, Builder, etc) for the duration of the building (until the building is demolished for another rebuild in the future) or the individual's LIFE, whichever is later!!

Come to think of it, I may not be clear on my earlier post.

To put it in another way to help understand:

My name & NRIC is registered as licensed holder of the builder. When I complete a building, I have to endorse the Builder's Certificate (part of various form needed to submit for TOP by law). My personal liabilities on the "As-Built" building (excluding any additions & alteration by owner after I hand over) is only absolved after I passed away or after the "As-Built" building is demolish for purpose of rebuild, etc, whichever is later.

This applies to the Architect, Professional Engineer, etc.

[fitz00 0]

1 minute ago, 3Cube said:

My name & NRIC is registered as licensed holder of the builder.

hi @3Cube just to be clear I'm not asking for anyone to come up with slip shod or dangerous designs that a builder/PE/architect has to sign off on. I completely understand this and that is not what I'm asking.

The reality of the situation now is that I will have to build a smaller house in order to fit my budget, or take on a renovation loan to build the house I want. My question is simply whether retaining the existing structure would save on costs and I think @snoozee's answer was very helpful.