Archive for September, 2010

I Have Just Received The Finished Construction Version Of The Thai House Plans To Build Our Retirement House In Thailand

Yesterday, September 29th, 2010, I received a set of construction drawings from our Thai architect to allow us to move forward on the road to building our retirment home in Thailand.

The house plans consisted of a set of very detailed Thai house plans, 46 sheets in all covering, Architecture, Structural, Electrical and Sanitation works.

I was delighted with the quantity and the quality of the drawings. I will describe what I received here in the post and show one or two of them but to do justice to the house drawings I have displayed them in the Galleries Section of the website.

Or you can go directly to the Architectural Construction Drawings Gallery

Samples Of The Thai House Plans – Construction Drawings – Designed By Our Thai Architect In Bangkok

Image of Thai House Plan Pakchong 2nd Floor Plan A07

Above, a sample of one of the construction drawings. This is the architectural layout for the second floor.

Image of Thai House Plan Pakchong End Elevation 2 A10

Construction Drawing Our Pakchong House End Elevation 2

Above, another example of one of the construction drawings. This is the front elevation.

Image of Thai House Plan Pakchong End Elevation 1 A09

Construction Drawing Our Pakchong House End Elevation 1

And above is the side elevation of the drawing for our our retirement home.

Image of Thai House Plan Pakchong Section BB A14

Construction Drawing Our Pakchong House Section BB

Above, another sample of the Thai house plans designed by our Thai architect. this time it is a section through the house that is shown.This is the last of the Thai house plans that I am displaying in this Post. I will be uploading more of the Thai house plans to a separate web page.

How Many House Plans Do You Need To Build A house In Thailand And What Level Of Detail Is Necessary?

There is a minimum quantity and level of detail that your house plans need to satisfy in order for you to build your hosue in Thailand. The minimum level depends upon the size of the house (i.e. how many rooms) the capability of the builder and the degree of control over the detail in the finished article that you want.

For our small house to be built in Pakchong, it is only 200 m2, our Thai architect has produced a set of house plans of construction stage quality and comprising 47 sheets of drawings. Here is a summary of what the set of construction drawings comprises:-

Summary of Construction Drawings to Build a Retirement House in Pakchong Thailand
Drawing Type No. of Sheets
Architectural Construction Drawings
Plans 4
Elevations 4
Sections 2
Details 9
Specification, Materials, Miscellaneous 5
Total 24
Structural Construction Drawings
Plans 5
Details 3
Specifications, Miscellanous 3
Total 11
Electrical Construction Drawings
Plans 4
Specifications, Miscellanous 2
Total 6
Sanitary (Plumbing) Construction Drawings
Plans 2
Specification, Details, Miscellaneous 4
Total 6
Total Number of House Plans for Construction 47

Received Today The Report Of The Site Soil Test To Determine The Thai House Foundation Design

Today (September 23, 2010) I have received from Thailand the report from the survey company, commissioned by the Kensington Company (our architect in Bangkok), who undertook the site soil tests that will be used to determine the design of the foundations for our retirement house in Pakchong, Thailand.

Photographs Showing The Soil Tests Being Undertaken On Our Land

These two photographs were taken on September 8th, 2010, at the land we intend to build our house to retire to at Pakchong, Thailand, and show the soil testing team at work on site. The rig you can see is the rig for the Standard Peneration Test (SPT) used to test the soil from which the safe ground bearing pressure is determined.

Site Soil Test Thailand Borehole No. 1

Testing The Soil On Our Land in Pakchong - Borehole No. 2

Site Soil Test Thailand Borehole 2

Testing The Soil On Our Land in Pakchong - Borehole No. 2

What This Report Tells Me About The Design Of The Foundation Design For The Retirement House We Will Build In Thailand

First and foremost, although the report of the soil tests is interesting information for me, it’s prime purpose is to give to the structural engineer the information he neeeds to design the concrete house foundations.

The report is highly technical and I had to engage the help of a civil engineer friend of mine to confirm my interpretation of the 32 page document, entitled “Survey Report, Subsoil Investigation, Private residence Project, Ampoe Pakchong Changwat Nakhon Ratchasima”.

(By the way “Ampoe Pakchong” means “District of Pakchong” and “Changwat Nakhon Ratchasima” means “Province of Nakhon Ratchasima”. Ampoe is often written as Ampur)

There are three key pieces of information in the soil investigation report.

Soil Type

The type of soil changes at 1.5 to 2 m depth below ground level. The top layer, down to 1.5 to 2 m, is what is called “very stiff clayey silt”. This has a good bearing pressure when dry, but when wet rapidly becomes saturated and turns into a slurry which cannot support much weight. Foundations should not be places in this layer of soil.

Below that there is a layer of “very stiff to hard silty clay, some sand and gravel”. This has a good allowable bearing pressure and is where the foundations must be formed.

Depth Of Concrete Footings

The report shows that the foundations (footings) should be located at 2 m below the ground floor level. That means that the builder must excavate 2 m deep to place ths foundation pads.

Safe Ground Bearing Pressure

The safe ground bearing pressure (allowable soil bearing capacity) is given as 26 to 35 t/m2 (ton per square metre or 260 to 350 kN/m2) at a depth on 2m.

The safe bearing pressure is the safe pressure that the soil can be loaded to. If the safe bearing pressure is divided by the total weight of the house the result is the area of foundations required.

The above is a very brief summary of a 31 page report. For more detailed information on foundations design and the importance of undertaking a site soil test go to the “Site Testing Of The Soil For House Foundation Design” web page.

Concrete Pad Foundation Design

The information in the site soil test will now be used by the structural engineer employed by the Kensington Company (our architect in Bangkok) to calculate and design the concrete foundations for our retirement house.

We Are Moving Closer to Our Dream Of Retiring In Thailand

The last week has been really busy and we have moved forward a couple of steps towards our dream of finally retiring in our dream house in Thailand.

We have received a set of 19 almost complete drawings from our Thai architect to review and Kanyah has booked her air ticket to visit Thailand on 23 September 2010.

Thai Architect’s House Plans Received For Review

As you know from the Post “A Thai Architect In Bangkok Is Making Our Retirement House Plans“, we have employed an archtiectural company from Bangkok to design our retirement house in Pakchong, Thailand. I have even posted images of some of the preliminary drawings they have produced for us on the Post “House Plans For Our Retirement House Produced By A Thai Architect“.

Now, we have received 19 construction drawings that are 90% complete for our review. I estimate there are about another five or six drawings to make, bringing us to a total of around 25 drawings. That is a LOT of drawings. I’ll be uploading them to a web page when I have time. If you want me to let you know when they are ready to view online please join the Announcement List and I’ll send you an email when they are uploaded.

The architect has said that he expects these to be complete before the end of the month. So, at the end of September 2010 we will have a set of drawings that we can use to:-

  • Submit to the Or Bor Tor Office to get the Building Permit.
  • Issue to Thai builders to get quotations to build our retirement house in Pakchong, Thailand.
  • Form as part on a contract with our selected builder to construct the house.
  • Build the house from.

All that’s very exciting but nothing in Thailand will happen while we are here in U.K. That’s why my Thai wife, Kanyah, is going to Thailand in a weeks time.

Kanyah Is Going To Thailand to Build The House

Kanyah has her air ticket booked for the evening flight from London Heathrow to Bangkok on Thursday 23 September 2010.

In Thailand she will have a lot to do to get the house-build started. Our original target was to have the house plans finished by the end of August, start building in September and have the house finished in time for me to stay in on my Christmas visit. That has all been put back now, not only because the house plans aren’t finished yet, but also because we are beging to realise the difficulties we will be facing.

The difficulties in building our retirement house in Thailand mostly lie in Kanyah’s lack of knowledge about construction and project management. Therefore she will need my help to:-

  • Review the builders’ quotations
  • Explain to the builder any changes we want to make from the Tender drawings
  • Negociate and agree the details of the contract with the builder
  • Obtain and finalise a contract with the builder

So, because she has so much to do before we even get to that stage, we have agreed that the construction will not start until my planned visit to Thailand on 19th December 2010.

Until then she has plenty to do including:-

  • Collecting our new Toyota Pickup from her daughter’s house in Bangkok and driving to Pakchong.
  • Finding some reasonable accommodation in Pakchong. Most likely to be “The Mansion”.
  • Receive the hard copy version of the final Construction drawings from the architect.
  • Decide on all the finishes and fitting fopr the house. things like floor and wall tile patterns and colors, wood floor type and color, bathroom fittings etc.
  • Submit the Construction Drawings to the Or Bor Tor Office and receive the Building Permit.
  • Arrange temporary electrical and water supplies for the construction.
  • Get the land cleared of vegitation ready for construction to commence.
  • Make multiple copies of the Construction Drawings.
  • Locate some Thai building companies and give them a pack of Construction Drawings so that they can prepare a price to build the house.
  • Receive the prices to build the house from the builders.
  • Learn to use email so that we can exchange information over the Internet. Yes, she has no idea how to use a computer and has never sent an email in her life.

In addition she has to get a Thai driving license and renew her Thai passport.

Quite a lot of things for her to do, before I arrrive in December to help her get the house build under way.

Site Testing Of The Soil For House Foundation Design

My architectural and design company, from Bangkok in Thailand, has arranged at my request to send a team to the house site in Pakchong to test the soil so that the foundation design of our planned retirment house can be finalised.

The test will be what is technically termed a “Standard Penetration Test” (SPT) and will start on 11th or 13 th September 2010 and a Report will be produced.

For more detailed information about how to determine Ground Bearing Pressure (GBP) and how to correctly size house foundations refer to the Thai House Foundation Design web page.

Disclaimer

What follows below is what I have learned about this soil testing procedure so far and no doubt as the investigation proceeds I will learn more.

Please take this article in the manner in which it was written – In good faith and with limited knowledge. I am no expert in this subject and cannot take any responsibility for any events that may occur by you taking any action as a result of reading this article.

Remember that all this is new to me – this is the first time I have had a house designed anywhere – let alone in Thailand!

Always have a properly qualified engineer to design your foundations for you!

What The Standard Penetration Test Will Achieve

In simple terms, the (SPT) test will determine the Ground Bearing Capacityof the soil, in other words how much weight the soil can support. This is measured (in Thailand) in tons per square meter. (Ton/m2). In the metric system the units are kN/m2.

From this, the size of the foundations necessary to carry the weight of the house can be calculated. Of course the weight of the house when contructed and in use has to be determined first.

How Important Is It To Have This Soil Test Carried Out?

To me it’s vital. After all that’s why I am paying for the test to be carried out. As I mentioned above I’m no expert in these matters so I am proceeding cautiously. I have been told by a civil engineer here in the UK that there are many reasons why the ground bearing pressure can vary significantly even on the same plot of land. This can be because the type of soil varies form location to location. Another big factor influencing the soil bearing pressure is whether the soil is compacted i.e. undisturbed or whether is is loose i.e. it is is soil that has been placed on the lad – often to fill a hole. In our case in PakchongI do know that the soil is agricultural land so it will have been ploughed to a certain depth.

However, this test is not always performed when designing house foundation and there are several reasons for this.

  • Sometimes it is not necessary to undertakea soil test for an individual property because the load bearing capacity of the soil may already be know for the region and held on record either with builders or piling companies or in the local Land Office. This information may have come from tests undertaken by other companies for other projects.
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  • Another reason that a Standard Penetration Test may not be required on a small house is that the load bearing pressure of the soil can be approximately determined by a knowledgeable geotechnical engineer from a knowledge of the soil classification. Tables of bearing capacities of various types of soil (such as rock, clay, gravel, sand etc) are readily available. In fact the British Building Regulations Approved Document A at table 10 gives the foundation sizes for various types of ground for houses of various weights.
    -
    So a good geotechnical/civil engineer with some local knowledge may be able to estimate a suitable safe size for foundations for a small house like the house we are planning to build in Pakchong. In case there is any suspicion of the type of ground, the foundations can be slightly oversized. This may be an unnecessary expense but the additional cost may only be a small percentage of the total house cost.

Design Procedures And Responsibility For Foundation Design In Thailand

I have been advised that it is common in Thailand not to finalise the size of the house foundations before appointing a construction company to build the house. In this case the design company makes an assessment of the foundation design based on ‘common practice’. The builder then takes responsibility for the foundation design and obtains the load bearing capacity of the soild to do so, either from local knowledge, existing data or by means of soil tests.

To me, this has several disadvantages and issues.

  1. The design company has to sign the drawings and provide the calculations for the foundation design. I don’t see how that can be done if the ground bearing capacity of the soil is not known.
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  2. The Or Bor Tor (The land office in Thailand where the house plans are submitted to apply for a building permit) will check the structural calculations. If these are not based on a knowledge of the actual load bearing capacity (that the Or BorTor Officer may well know because he deals with the applications daily) the calculations may not be accepted and a building permit may not be issued.
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  3. The local builder may not have the necessary knowledge and skills to determine the load bearing capacity and to re-design the foundations if necessary. Yes, a large company may have a qualified enginer, but I’m expecting to find a small, local builder in Pakchong who may not have the necessary expertise. By the way, I’m told that there is a Thai regulation that applies for buildings over 150 square metres and it stipulates that the builder must have a qualified and knowledgeable engineer to supervise the project to control the construction process. Well, judging by the coments on so many Thai websites, that expertise is often not applied very well!
    -
  4. I will be unable to award a construction contract with a known fixed scope, price and timescale and will be at the mercy of the builder when it comes to price and programme.
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  5. Responsibilities become blurred. the designer is effectively passing the responsibility for foundation design on the the builder. The builder may not accept this.
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  6. Extention to the programme. I am having the soil bearing pressure tested and the foundation design finalised in parallel with the preparation for the construction drawings. If this work is handed over to the builder there will be a delay to the construction programme while it is carried out.
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  7. Design costs will be more expensive. The design company has spent time designing foundations and making drawings, including steel reinforcement details. This will may have to be repeated by the builder and he will charge me for it. Double work. Double cost.
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  8. I may not be in Thailand at the time of the build. The works will be supervised by my wife, Kanyah, who does not have building knowledge and she would not understand the commercial implications of undertaking the soil test and the foundation (re)design. Yes, we will appoint an inspector to take care of the technical details of the build, but he will not be expected to manage the builder’s activities.

More Information On Foundation Design

You may not be interested in how to design house foundations and I can well understand that. But you ought to understand how foundations are designed so that you can decide whether to design your house the way I am and let the design company finalise the house foundation design or to do it the common Thai way and let the builder do it.

I have therefore written an article about foundation design and the effect of land bearing pressure for the complete novice.

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