QUOTE(Hastebreak @ Jun 6 2025, 04:34 PM)
I do not know if you know... But an interior designer isn't a one-man knowing all about renovation...
Are you aware that tiling a tile has its own ISO-certified standard of practices?
Do you think an interior designer know all this?...
Even architects isn't familiar with it... nor a property agent / developer... They may know, but they ain't true know-how experts in the fields...
Having the right screed layering / adhesive / water-proofing layer, the right tile installation method for mortar application has its own protocols (to prevent spot bonding and all that)...
In fact, not all tiles chosen by you works the same for all areas of application... And in the Malaysian industry (which I do not need to tell you how loose we are), there's a lot of con man / uneducated folks working in this line because the industry tends to permit low-education professionals with barely suffice training...
This is also why the Australian government officially certify plumbing and renovation jobs... because it literally is composed of bodies, regulations, updated rules, materials science, and all that which is used to train these professionals...
This is also why the Malaysian infrastructure is lagging behind in terms of decades... (And only just recently they enforced a minimum of SPM certification for property agents, as well as having them undergoing sales training in a once-upon-a-time era when uneducated / untrained folks could become one --- which spoils the real estate industry)...
As you shared, materials built upon are the most cheaply found building blocks to put up a decorate... and they do so because they may want you to tear it down for a new renovation so money is back into their pockets...
So as roofing...
So as piping... There's a complete pump engineering profession centered to the size of the piping, to the number of heads (resistance) for flow rate... Hell, even choosing the right pump according to the size of the house differ...
You need a team of specialised experts to advise you accordingly... Not a one-trick pony that Malaysian folks tend to think it's that easy...
If you do not believe me, feel free to Google any of these step-by-step...

Edit - Reason: Typo.
I doubt we know each other. Unless you are working closely with MoF.
First of all, thanks for your effort in your reply. Much appreciated.
Of course we know they cannot know everything. No one does except quacks.
But at least you humbly demonstrated and stated the limitations of an interior designer.
So we begin by stating, what is an interior designer.
I malas, so I will just copy and paste from wiki:
"an interior designer is someone who plans, researches, coordinates, and manages such enhancement projects. Interior design is a multifaceted profession that includes conceptual development, space planning, site inspections, programming, research, communicating with the stakeholders of a project, construction management, and execution of the design"
Which is a fair definition for me right?
The house tiling / water proofing / major plumbing and toiletries / electrical wiring, including fans/lights/and aircond have ALL BEEN COMPLETED before the unit was handed over to the ID team for interior furnishing.
Mine is already a completed renovated house.
Hence, the interior designer did not need to handle the task that you have elaborated.
Really, the bare minimum I would ask of them is to install furnishings without further damage to my unit. But even that was too much to ask these days I guess.