3Cube

Strongly advice in your case for Semi D, spend money on Professional Engineer is more than enough. The PE should be able to get an Architect (ie: minimised fees) to endorse for Authorities' submission. The layout you can give input of your requirements to the PE or interior designer. This way you save a lot on consultant fees & all your budget is properly used (ie: no wastage, everyone actually does work for the money paid). Unless you are budgeting anywhere exceeding 2 million for your job (which I doubt so) then go for the full team of consultants. The QS & M&E will be laughing all the way to their bank.... (Easy money for them)

Generally, if you are building semi-d or terrace, M&E Consultant is unnecessary as the Licensed Electrician, Licensed Plumber / Gas, Air con sub contractor can double up for authoritirs' submission requirement M&E Consultant is generally needed for large Commercial job like shopping complex Government Building where M&E is more complicated.

What you want is basically increase of build-in floor area which means added structural floors, which in turn means added loading on the current foundation. High propability that upgrade / addition of foundation is a must. You people should understand extension of this nature is not like Lego where you can add or remove without thinking of overall foundation support.

Google for pivot door & look under google shopping tab. Just get the pivot ironmongery & get your door contractor or handyman services to install.

In addition to my last post, you should note on the following: If your job is going thru the tender bidding process, The section for piling will contain provisional penetration length in order to establish the total amount. This amount will be subjected to variation order to adjust for actual pile penetration record as witness & endorse by the RTO (Resident / Registered Technical Officer, previously also known as Clerk of Works). The provisional length is to enable completeness & uniformity of all competing bids for fair comparison during the tender bidding stage.

I feel the need to clarify in case anyone was comparing cost & to avoid misconception. The price for piling varies due to different land / soil / earth condition. This also depends on the actual driven penetration depth. Hence if anyone is comparing cost, you should be looking at the rate per m (also rates for mobilization, etc) instead of overall total amount of the piling item. Usually piling works contractor depend on the bore log of soil report, site location's conditions, pile sizes & the piling plan to work out the rates.

Structurally speaking, all building must have foundation. The sub-catagories under foundation type are Pile Cap (for caping a pile & facilitate load transfer), Footing (mostly not capping any piles but sometime, depending on soil condition, may cap Bakau Piles). Of course things like reinforced concrete pile are part of the foundation (by definition structural element under the building embedded in earth / soil) What I'm stating here is just a simplified explaination for laymen's understanding. Bakau pile are basically timber in nature (or Bakau tree trunks to help you understand visually). It is installed either laying horizontally (usually in the case of drains, culverts laid parallel to lenth of drain or culvert) or vertically driven into the soil. Just google to see how Bakau pile looks like. I would strongly urge you to check with a structural Engineer on contents of my post. I maintain my content in my previous post on this thread is true, based on the numerous project I've personal involved over 20+ years. Please understand it is simplify as I don't meant the post as a lecture but more of general knowledge to help laymen's visualisation. Sort of a non-numerical statistical summary. In your post as attached, you mention raft foundation. Basic analogy, Raft foundation is like visually the building is a boat on water (soil) where the raft foundation is like the hull (base) of the boat in direct contact with the water (soil). I speculate this is why it's named as "raft". This is design / use to ensure even settlement of building on the earth / soil.

Plate Loading Test is basically stacking of huge stones on top of the pile position to be tested. The Stones is meant to simulate the designed bearing load for the particular pile to check the pile's effectiveness to bear the load. This is usually carried out for big, tall commercial project such as production factories, skyscraper, HDB flats. Usually for landed residential such as terrace, bungalows, semi-detached house, a PDA (Pile Dynamic Analysis) test would suffice most of the time. Such Plate Loading Test would usually be required if there are some irregularity with the pile's penetration depth, PDA results, etc.

I'm sorry if you feel that way. But I'm just stating the facts. You are most welcome to dispute my post.

There should not be any such contractor. These are not generic equipments or materials like cement, bricks & the likes. This is the gist of free market economy. If you invent or is a manufacturer of something proprietary, you can basically charge anything & be rich!!! Think logically!! A branded equipment usually has proprietary parts made by that particular brand. If there indeed were third party contractor, how would these company be able to earn any profit if they can only buy the parts from the brand. It is also likely the schematics are proprietary & you risk messing up the system, along with any software safety features, which renders the lift unsafe to use. This is applicable as with all mechanical equipment. Even if there are such "authorized" contractor, the price; logically, would not deviates a lot. Think PROPRIETARY then you'll hopefully understand. Also, let this be a fair warning to all future potential lift owner. Don't just look at the installation cost & buy the cheapest. Ask about the maintenance aspects.

The Vent is meant for air to flow into the shelter. Usually position on top of the steel door. I've constructed one house with a basement that consist of a bomb shelter, Entertainment room, Maid's Room & an extra room. Water table is non-issue as the basement floor / walls concrete were mixed with waterproofing additive chemical & another layers of waterproofing were applied on external basement wall's surface before backfilling of earth is done. I've also designed another property with a basement that has rear, left & right walls. The front wall was omitted to serve as vehicle's access (ie: carpark entrance.) In such cases. I position the bomb shelter in the rear of the "basement" & allocated a lot of softscape design by working with a landscape architect to minimize / neutralize vehicular smoke.

A basement shelter frees up option / space in your 1st storey for other purposes (ie: space planning for living room, dinning room, kitchen, etc). Not to mention the asthetacical appeal benefits as some people may feel the steel door or the steel vent opening unsightly. You also don't have to based your interior design around the shelter's unsightly doors, vent, etc If you have the budget, I strongly encourage it. You can have one of the shelter's walls to double up as part of basement wall. You should be aware of the requirement by Civil Defense on the internal floor clearance area & the volume in relation to type of housing / occupant's number. Google the "Civil Defense bomb shelter handbook" & download it for additional information.

My opinion on Performance Bond: This is the assurance given to the employer (ie: property owner). In my past experience, there are numerous cases where owner runs out of budget & fails to pay which in turn affects the project cashflow & the contractor becomes the financier instead. This almost always ends in messy court proceeding. It's a double edge sword. In most of my own company's turnkey job, the alternative way to assure the owner can be to propose a higher retention sum in lieu of the Performance Bond. This way, the builder do not need to set aside capital for collateral with the Insurer to secure the bond. The added retention on progressive completed works serve as assurance for the owner. This ensure all finance are fully focus on procuring the materials & labors to complete the works in timely manner.

Clarification on Retention Sum" There is a limit on this. The mechanism is as follows: 1) Every monthly payment, Ten percent is deducted from the accumilative total claim. 2) When the deducted amount reach the limits as spelled out in the SIA contract's appendix, no further deduction will be made. Example" Assume Contract Sum: $1 Million Contract Period: 10 months Retention: 10% (Limited to 5% of Contract) 1st Progress Payment: Accumilative Claim: $100,000.00 Retention: $10,000.00 !st Claim Payment: $90,000.00 3rd Progressive Payment: Accumilative Claim: $330,000.00 Retention: $33,000.00 Less: Claim Paid to date: $200,000.00 3rd Claim Payment: $97,000.00 5th Progressive Payment: Accumilative Claim: $600,000.00 Retention: $50,000.00 (Limit of Retention) Less: Claim Paid to date: $400,000.00 3rd Claim Payment: $150,000.00 In the example, The $50K will apply to all claim from 5th Claim onwards until the final account. Half of this will be release upon TOP completion with final half upon DLP (Contractually known as Defects Liabilities Period as spelled out Appendix in SIA Conditions of Contract)

Most of the time, the 3rd Parties Liabilities clauses in the Contractor's All Risk Insurance Policy (to be procure by the builders before contract commencement) will apply in this scenario. Say the cost of the repair as $X. The Excess in the insurance is $Y. The builder will claim from the insurance company $X - $Y. If the repair cost is less than the Insurance Excess, then the builder will do the repair themself.

Just my personal opinion on the issue at hand. Whenever the Professional Engineer design a structure, there is a safety factor. Maybe I'm wrong but I remember I was taught this is usually a factor of 2 or more. This means, THEORETICALLY, the building structural elements can take up twice the design load. Having said that & for structural safety consideration. this does not mean that stacking up another floor is implied to be acceptable. This should be the concept even when the scenarios is that the structure was design with intended consideration for future "stacking" or addition of floor or floors. Point number 1: In the past, I had involved (before I started my own construction firm) in various A&A jobs where the Professional Engineer, engaged directly by the property owner, simply just added (allowed by the regulation back then) steel beams, concrete / steel bars reinforcement, etc before stacking another floor (constructed with combination of steel beams & concrete reinforcement). In such cases, leakage usually occurs due to the nature of the work. Hacking of the old concrete is required in order to form the joint for the strengthening added beams, columns, etc. During hacking, the old concrete surface is vibrated to break the concrete. Hence cracks appear. Nobody will be able to control the extent of the crack. It maybe hairline cracks which will enlarge over time which eventually leads to leakage, sometimes at weird spots far away from the construction joint. Point number 2: The safety factor to the entire structure that I've mention above should remain status quo after addition or stacking is done. This should never be perceive as overkill. Due to time factor (ie: from completion of old building to start of new extension or addition) & records accuracy, the structural calculation might be flawed. Worse case scenario you might end up with a lower safety factor than intended. My thinking here is based on "Murphy's Law" which states: "Anything that can go wrong will go wrong" "If everthing seems to be going well, you have obviously overlooked something" Better to be safe than sorry. In closing, these are some of the reason why my company will only focus on total demolition / rebuilding & minor renovation works.

Just a important clarification on your post. Technically metal plates cannot be build in line with boundary. Your word "technically" should be change to "in theory". Why is this? Because of the rig / machinery's clam would have to hold the plates to drive the plate into the earth by hydraulic (Vibration / pneumatic device not advisable to avoid damaging neighbors' property). Due to the clam, some working space is necessary. Also the outside of the clam cannot touch the neighbors' party wall for obvious reason. Unless whatever is over your boundary is empty plot of land (ie: earth with no building structure, not even carpark with concrete on earth). Technically & practically the plate cannot be in line with the boundary.

Forgot to mention the estimate of "upwards of 225k" is pre COVID. Which means it may be at least 20++% more costing. Not to mention a longer period for submission & construct the temporary strutting / shoring works.

Beside all the ERSS as mentioned, you should be aware of strutting works needed to prevent your neighbor's house from collapsing on your plot. Double if yours is a terrace house as strutting needed of both left & right neighbor. Important to note on waterproofing issues in your neighbor/s related to the aforementioned strutting. This means you have to be aware of third parties' liabilities within the Contractor's All Risk Insurance Policy which your builder must procure before construction commencement. Overall, the ERSS, Strutting & the separate ERSS Qualified Registered Professional Engineer will be upwards of 225K. This is not including the actual concrete, steel, etc to form your basement. Also, depending on your project Professional Engineer's (not the ERSS PE which means you'll need 2 PE for the job) structural design of the foundation (ie: Pile Cap or Footing), added ERSS is needed for the foundation's pile cap or footing. Finally, there is regulation / requirements to the draining of underground water during excavation. Just thought you should be know.

I strongly suggest you chat with the officer or any architect. I have personally involved in physical drawing / drafting of plans as this is my job, aside from other thing such as the construction. Another words, all the way from no plans to TOP, & for many project over 25 years, noting all the updated regulations over the years. Not trying to argue but just trying to correct the understanding.

Go to current URA website & see again. There is a statement on GFA (Go to URA site, Guideline, Development Control, Residential Handbook, Semi-Detached Houses, Introduction): "The permissible Gross Floor Area (GFA) for landed housing is resultant of the allowable building height and envelope." The statement is same for Bungalow (Detached House) & Terrace. For Strata Landed: "A strata landed development site may have a mix of bungalows, semi-detached houses and terrace houses occupying a common development site with shared communal facilities and a single vehicular access point. The building footprint of each strata landed unit shall have minimum ground contact of 50sqm. All other requirements are guided by the envelope control guidelines and respective parameters for the relevant landed housing type." Hence, it's implied if your property is a semi-D or a terrace or bungalow within a Strata Landed, the GFA statement shall be applicable. If GFA is not applicable, then why the statement by URA in the first place. Also why the word permissible?? My understanding is that plot ratio is "relaxed" since the various height control, envelope, requirement, etc would establish the allowable GFA.

You didn't notice before this I said "Similarly as in my post in another thread extracted as follows:" Please read before comment. All architectural plain contains a site plan with a GFA calculation which is required as part of Architect's declariration, & submission.

The Architect that design & endorse the authorities approved plan for your property would have design shelter in if it is allowed under the authorities regulations & design guidelines. What I'm about to suggest is NOT LEGALLY ALLOWED but easy to remove when instructed by authorities to do so. Or you could just install a retractable shelter or just have some picnic umbrellas with tables & chairs. Not exactly aesthetically pleasing. Other than this, there is nothing you can do legally. Similarly as in my post in another thread extracted as follows: Upon enlargement of your picture, you should note the words "For maintenance only". There is a reason for this indication on Architectural plans as submitted & approved by the authorities.. As extracted from URA website under the link "GFA": For development control purpose, Singapore uses a Gross Floor Area (GFA) system to work out the bulk and intensity of a development. The Gross Plot Ratio (GPR) for a specific development site is defined as the ratio of the GFA of a building to its site or plot area1 . The allowable GPR of a development is guided by the GPR specified in the Master Plan (MP). This GFA handbook explains which area or space of a development is included or excluded from GFA for development control purpose. As a general principle, all covered floor area of a development and all uncovered area used for commercial purposes are included as GFA, unless otherwise exempted. This is regardless of whether the spaces are accessible or usable. GFA is the total area of covered floor space measured between the centre line of party walls, including the thickness of external walls but excluding voids. So likely in your case, if you cover that portion of your property. That is "adding" GFA without approval. This does not have anything to do with setback. The best person to answer this will be your Architect, who is the sole qualified person (as define by the Authorities) in charge of calculating Plot Ratio, GFA, etc followed by the endorsement & submission. Interior Designer, Professional Engineer, Builder is not involved in this aspect. Go to URA website & you can have all the information.

Another way is to apply SKK's Elegantstone which aesthetically mimics stones finish at fraction of the cost. It's basically: A water based high build acrylic resin texture coat incorporating natural granite chips. As described on SKK Website Just for information

Tiles, Stones, or Marble cladded on external boundary wall serves no purpose other than just for aesthetic, decorative view. However, if you have a spot (ie: garden, pond or pool) in your front, side or rear setback area, it'll be nice to incorporate some stone cladding design with waterfall feature just for that section. The rest just plaster & paint will be enough. Just a suggestion.