I'm trying to build a four-story house in Kathmandu. I already have land. What would be the cost nowadays to build a medium quality home with about four rooms on each floor?

Around 225k and takes around 11 months. Sounds joke to many but things are very expensive and labour is out of control. Plan twice and half time for finishing. By the way, you could bring cost down by 40% if you can give 10 hour per day towards your project.

In past I had mentioned about labor: no matter which country you are in,if it is hourly basis it will progress on snail basis. If you give on contract: it will go fastern but in both cases quality is always compromised. If it is your first construction work :you will be listenig to your engineer, not all engineering works will good: it is like mechanic.
In 2010 I met a lawyer whose house was almost finished stucturally, at hardware store. I bullshit him and he wanted me to check his house.
I pointed : In the stairs should have transparent glass so the house would have more light instead of tiny kind aakhi jhyaal. Second question: where is car garage?
Third :your toilet Should be Dry toilet concept, that is very simple thing to do is , keep the shower all the way in and the comot as you inter. His was just opposit. The toilet floor should be non slippery, just to save the medical bill and injury.
He could not see all those simple thing : because this was his first house. If you are here and wanted to build a house : you should have some one who knows how to deal with people as well where to get things. Water is another problem.

no electricity no water, why u want to spend so much money in Nepal, rather buy a business in foreign countries

The house is for my parents since our other house in KTM is getting old now. I want them to be safe in the event of a quake or something. So cost kati parla ta? Tetti bhanidiuna, by the 225k for a four story house is probably including some land as well. I just want to get an idea about the cost of the structure only. My family can supervise the project everyday since this new house will be close to the old house.

You might wanna elaborate a bit as far as your description is concerned. Your description is pretty vague. Further, what sort of house do you seek? What about furnishing and amenities? Also, what's the size of land?

Land is about 8 aanas in Baneshwore. House would be an apartment style type (wanna rent out the bottom floors), not bungalow type, four stories. Furnishings we already have. Amenities bhannu parda Bathrooms (5), tile finishing on three, wood finishing on the top floor.

Basically the objective is to build your average four story home. for example the one below

http://1ropani.com/HouseDetail.aspx?ID=4653

Hakim_saab,
I have not built any houses in Nepal but I have in the US. Here are my opinions:
If you and your parents are not in need of money, do not build a house with the purpose to rent the floors. Build a simple one storey house just for the purpose of the family. The quality of life will be much better for your parents.
Secondly, try to avoid floors if your parents are getting older. Many people do not realise this, but when you get older it gets very hard to climp up and down. So try to minimize the steps and avoid floors if you want it to be easy on your parents.
I am not sure which way your land is exposed, but try if possible to expose your house towards South and may be East and West to get the most amount of sun light and heat during winter.
If you want to know more, let me know. But I can't help you with getting labors, material costs in Nepal.
In the US or in Europe, for a regular house you can count $1000 or 1000 euros per m2.

around 80 lakh.
below ground floor: 20 lakh , the base
4 floors : around 15 lakh each * 4 = 60 lakh

there is 2 method for building the base of the house ( जग ), one is called "hatti paila" another is the one with underground parking type( dont know the name), the first one is considered bad but still widely used (banned in some city) and cheap to build,( under 10 lakh).
the labor cost is under 5 lakh each floor including everything , plumbing, electricity, tiling, all. ( it is included in my estimation above)

I personally think that the figures mentioned by "thatguy" seems reasonable, (a little bit higher side) but I think 70 to 80 lakhs should be taken into consideration.

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Don't think this is bullshit. There are scientific reasons for all and the expert will tell you in detail.

You have not mentioned the square footage of your to be built house. You can contact any architect/engineer and they can give you price/sq. ft and you can estimate total cost on that basis. You can find the number or emails of such builder/architects on google. It used to be Rs. 1200/sq. ft one decade ago.

according to new mapdanda cost of building one story haouse in 4 ana land is 45 lakhs , add 25 lakh more on every storey u add so cost of building 4 storey house is 45+25 + 25 +25 lakh . cost of land is extra.

everyghting included in this price except land . thekdar takes 7 lakhs to build one storey house