Does 3 floors cost about 3X the first floor or less?

In this case a basic concrete construction with almost no wood.

One floor costs 2 million baht with a CPAC roof and concrete footings but no pilings.

With 3 floors the plan would be the same quality roof but I presume pilings wood be needed.

Note this is in Chiang Mai so pilings would not need to be as deep as Bangkok.

YES and NO

Just so that the above is in context.

A lot of the money goes in the fit out, not the actual 'Shell'.

So, if you were building a house to 'lock-up' stage then what you suggest is a fair assumption.

However, if you are including Bathrooms and Kitchens etc ... that does vary the price significantly.

The heavier (more stories) the building the stronger the footing though.

Actually the one floor example does not have a kitchen and the 3 floor example will also not have a kitchen. (There will be a separate open air type kitchen eating area outside.)

The one floor example has large footings but no pilings.

The number of bathrooms per floor will be about the same.

The 2nd and 3rd floor concrete beams and slabs would carry extra cost for formwork and scaffolding support and extra effort to bring up steel rebar and wet concrete.

Concrete on the 1st floor beams and slabs can be supported by compacted soil and sand though sides of beams should have formwork.

You need also to add in the cost of the staircase.

Edited November 30, 201312 yr by trogers

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Very, interesting!

I had no idea that the cost goes up for each additional floor.

In our case the roof is quite expensive so I thought there might be savings there...

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Very, interesting!

I had no idea that the cost goes up for each additional floor.

In our case the roof is quite expensive so I thought there might be savings there...

There is. You need only a smaller area of roof for the same built-in area.

Say 140 sqm floor area. Single storey needs roof area of 140 x 1.5 = 210 sqm

Double storey needs roof area of 70 x 1.8 = 126 sqm

Why would you change 1.5 to 1.8 in your calculations?

Why would you change 1.5 to 1.8 in your calculations?

The amount of overhang beyond the perimeter wall remains constant and is of higher ratio for a smaller floor area.

Foundation design, and thus cost, is dependent on geologic conditions onsite. Talking about CM vs BKK in general terms is dangerous, as the CM area has everything from alluvial plains to mountainside rock geology. For the latter, you might need no piles, but may have to excavate rock. For the former, piles are required for one story concrete house - for a three-story concrete structure, size and number of piles increases with added loading of multi-story construction in concrete.

Which site type do you have?

Foundation design, and thus cost, is dependent on geologic conditions onsite. Talking about CM vs BKK in general terms is dangerous, as the CM area has everything from alluvial plains to mountainside rock geology. For the latter, you might need no piles, but may have to excavate rock. For the former, piles are required for one story concrete house - for a three-story concrete structure, size and number of piles increases with added loading of multi-story construction in concrete.

Which site type do you have?

We are working with clay former rice fields.

The top 1.5 meters (.5 black clay, 1 meter red mountain soil only a few rocks) is loose soil so I don't count it

Below the top 1.5 meters is solid clay and we start serious digging for the foundations there.

So for a one story building piling is not needed as we have large concrete footings.

I imagine pilings will be needed when we are ready to start taller buildings.

Foundation design, and thus cost, is dependent on geologic conditions onsite. Talking about CM vs BKK in general terms is dangerous, as the CM area has everything from alluvial plains to mountainside rock geology. For the latter, you might need no piles, but may have to excavate rock. For the former, piles are required for one story concrete house - for a three-story concrete structure, size and number of piles increases with added loading of multi-story construction in concrete.

Which site type do you have?

We are working with clay former rice fields.

The top 1.5 meters (.5 black clay, 1 meter red mountain soil only a few rocks) is loose soil so I don't count it

Below the top 1.5 meters is solid clay and we start serious digging for the foundations there.

So for a one story building piling is not needed as we have large concrete footings.

I imagine pilings will be needed when we are ready to start taller buildings.

Is your architect & engineer advising you on this?

Precast concrete piles are normally used when building even single story concrete houses on former [flat site] rice fields in LoS, as long as there not large rocks mixed in the substrata. They're really not that expensive, and give you proper bearing capacity for building on alluvial plains such as are typical of Thailand flatlands rice field sites. There can be significant differences in capacity from one are of a site to another, which can cause differential settlement under building loading - extraordinarily bad news for concrete frame buildings. Assuredly, the local village-folk, who are evidently undaunted by their cracking and sinking homes, will tell your Thai friends/family that you are just another dumb farang wasting money driving piles.

If there is a major, long-standing developer's moobahn nearby with similar existing site conditions as yours, observe their foundations & footings and that is what you'll likely need for a proper foundation system - if you're building similar construction & geometry to theirs. Risk = reward, so if you are willing to risk your structure, want to save some money, and everything turns out well... it's all good. For me, I recommend hiring an architect who brings along an engineer.

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Very, interesting!

I had no idea that the cost goes up for each additional floor.

In our case the roof is quite expensive so I thought there might be savings there...

Of course the cost goes up with each new level. It has to. It's higher for a start therefore harder to build.

Scaffolding cost goes up.

I beams will be needed.

Engineers should be used.

Roofers will be suddenly working much higher up and this takes longer.

The list will grow.

Edited December 27, 201312 yr by krisb

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Very, interesting!

I had no idea that the cost goes up for each additional floor.

In our case the roof is quite expensive so I thought there might be savings there...

There is. You need only a smaller area of roof for the same built-in area.

Say 140 sqm floor area. Single storey needs roof area of 140 x 1.5 = 210 sqm

Double storey needs roof area of 70 x 1.8 = 126 sqm

I don't get these calculations.

Please explain for me?

What's the 1.5? is that for roof over hang?

Your calculations are wrong I think. Where is the allowance for pitch?

Foundation design, and thus cost, is dependent on geologic conditions onsite. Talking about CM vs BKK in general terms is dangerous, as the CM area has everything from alluvial plains to mountainside rock geology. For the latter, you might need no piles, but may have to excavate rock. For the former, piles are required for one story concrete house - for a three-story concrete structure, size and number of piles increases with added loading of multi-story construction in concrete.

Which site type do you have?

We are working with clay former rice fields.

The top 1.5 meters (.5 black clay, 1 meter red mountain soil only a few rocks) is loose soil so I don't count it

Below the top 1.5 meters is solid clay and we start serious digging for the foundations there.

So for a one story building piling is not needed as we have large concrete footings.

I imagine pilings will be needed when we are ready to start taller buildings.

Is your architect & engineer advising you on this?

Precast concrete piles are normally used when building even single story concrete houses on former [flat site] rice fields in LoS, as long as there not large rocks mixed in the substrata. They're really not that expensive, and give you proper bearing capacity for building on alluvial plains such as are typical of Thailand flatlands rice field sites. There can be significant differences in capacity from one are of a site to another, which can cause differential settlement under building loading - extraordinarily bad news for concrete frame buildings. Assuredly, the local village-folk, who are evidently undaunted by their cracking and sinking homes, will tell your Thai friends/family that you are just another dumb farang wasting money driving piles.

If there is a major, long-standing developer's moobahn nearby with similar existing site conditions as yours, observe their foundations & footings and that is what you'll likely need for a proper foundation system - if you're building similar construction & geometry to theirs. Risk = reward, so if you are willing to risk your structure, want to save some money, and everything turns out well... it's all good. For me, I recommend hiring an architect who brings along an engineer.

Yes, our engineer, architect, draftsman & chung (all local) all agree that no pilings are needed as well as the Chung at the local Tessabon where we got our building permit.

Apparently in Chiang Mai where we are no pilings are normal for one floor buildings. I do see some cracks in local buildings but no sinking. I also spoke with a friend (unrelated to the architect and builder etc) who is a civil engineer educated overseas who said pilings are not needed and not typically what causes cracks in floors and walls in Chiang Mai he said that from his observations it is poor building techniques.

Also pilings would not be cheap compared to our building costs without them. Perhaps adding 7% - I spoke both with builders and directly with piling makers. Note the piling makers could do the work for around 40% less than general contractors.

Costing this year single storey THB 6,000 sqm, 2 Storey THB 9,500 sqm. Basic Thai rooms, in this case was 50% more per sqm. Approx same cost with three quotes.

Very, interesting!

I had no idea that the cost goes up for each additional floor.

In our case the roof is quite expensive so I thought there might be savings there...

There is. You need only a smaller area of roof for the same built-in area.

Say 140 sqm floor area. Single storey needs roof area of 140 x 1.5 = 210 sqm

Double storey needs roof area of 70 x 1.8 = 126 sqm

I don't get these calculations.

Please explain for me?

What's the 1.5? is that for roof over hang?

Your calculations are wrong I think. Where is the allowance for pitch?

The ratio is from dividing the shaded plan area of a roof, including overhangs and covered porch, etc with the floor area enclosed by the perimeter walls.

I am guessing the price per sqm is without the roof. Do you know what would be a rough estimate for the price of a roof per sqm for a double story?

Thinking about having our house build, so a rough estimate would come in handy. Not yet sure it will be tiles or concrete.

I am guessing the price per sqm is without the roof. Do you know what would be a rough estimate for the price of a roof per sqm for a double story?

Thinking about having our house build, so a rough estimate would come in handy. Not yet sure it will be tiles or concrete.

Price per sqm of shaded plan area of roof can vary up to 2.5 times depending on the pitch, hip or gable end, any valleys, type of roofing material (clay tiles, slate, or metal or cement sheets, etc), quality of insulation, and factors affecting structural support.

Thanks for your answer.

Confirms I must add the price of the roof to the price of the floor per sqm.