Pile testing is the checkpoint that confirms piles are sound and can carry their load before construction continues. If the company you hire does not work to standard, the results may be unreliable and the report may not be accepted for permits. This article summarizes a 7-point checklist, with the questions to ask and the documents to request before you decide — usable for comparing any company.

What to look for in a pile testing company: a 7-point checklist

All 7 points are questions a client can ask before signing a contract, and each one has evidence you can request. The most important is point 1: a COE-licensed engineer certifies the results.

The figure below summarizes all 7 points on one page. On each card, the “Ask” line is the question to put to the company and the “Check” line is the evidence to request. The red card at the bottom right lists warning signs.

7-point checklist before hiring a pile testing company, with the questions to ask and what to check for each point, plus warning signs Conceptual infographic of cards in two columns and four rows. Seven cards are the article's seven-point checklist; each has an icon, the point number, its title, an Ask line with the question to put to the company and a Check line with the evidence to request. Point one, a COE-licensed engineer certifies the results, is labeled most important: ask who signs the certification and whether they hold a COE license number; check the engineer's name and COE registration number on the report; the icon is a signed and stamped document. Point two, correct standards and calibrated equipment: ask which standard numbers are used, both DPT and ASTM; check the equipment calibration evidence; the icon is a gauge dial with a calibration tag. Point three, real experience and track record: ask how many years, how many projects and what types of work; check sample projects or case studies; the icon is a house, a high-rise and a factory. Point four, the report can be used for permits: ask what the report contains; check the test method, result graphs and interpretation; the icon is a report with a graph and a certification seal. Point five, several methods within one team: ask which methods are offered and whether further in-depth testing is possible; check for Seismic, PDA, Static and CSL; the icon is four boxes for four methods. Point six, transparent pricing: ask what is and is not included; check that travel and equipment mobilization are stated in the quotation; the icon is a quotation with coins. Point seven, availability and service area: ask how soon a test can be booked; check that the company works in your site's province; the icon is a calendar with a map pin. The eighth card, on a light red background, lists warning signs from the article: no COE-licensed engineer certifying or only raw machine output, unable to state standard numbers, guaranteeing the results will pass, and unitemized pricing or charges added later. The bottom line notes that the checklist applies to any company and that real evidence should be requested for every point. 7 checks before hiring a pile testing company Conceptual infographic 1 Licensed engineer certifies Ask Who signs? Do they hold a COE license? Check Name + COE license no. on report Critical 2 Correct standards + calibrated tools Ask Which standard? (DPT / ASTM) Check Calibration evidence 3 Real experience & track record Ask Years, projects, types of work Check Sample projects / case study 4 Report usable for permits Ask What does the report include? Check Method · graphs · interpretation 5 Several methods, one team Ask Which methods? Further testing? Check Seismic · PDA · Static · CSL ฿ 6 Transparent, itemized pricing Ask What's included, what's not Check Travel/mobilization in the quote 7 Availability & service area Ask How soon can you book? Check Do they cover your province? Warning signs per the article No licensed engineer Can't name standards Guarantees a “pass” Unitemized / added later Applies to any company · ask for real evidence for each point Conceptual image based on the article
7-point checklist before hiring a pile testing company — each point has a question to ask (Ask) and evidence to request (Check). The red card lists the warning signs from the article. Usable for comparing any company. (Conceptual infographic · Image: SPN Soil Engineering)

1. Does a COE-licensed civil engineer certify the results?

This is the most important point. A pile test report that can be relied on must be signed and certified by a civil engineer licensed by the Council of Engineers Thailand (COE), with signature and registration number. If a company can only issue raw machine output without engineer certification, that report will be hard to use for a building permit application with the relevant authorities. Ask clearly who signs the certification and whether they hold a COE license number.

SPN engineering team installing a static load test setup to test pile load capacity on a construction site
A company that offers every method can recommend the test that best suits the job — a static load test setup per ASTM D1143 (Photo: SPN Soil Engineering)

2. What equipment and standards are used?

A reliable company must be able to state which standard number applies to each method, and that number must match the actual test method. The table below lists the main standards used in Thailand. See more at DPT standards for pile testing.

← Scroll to see the full table →

Reference standards for the main pile test methods
Test methodReference standards
Dynamic Load Test (PDA)DPT 1252-51 and ASTM D4945 (current edition D4945-26)
Seismic / Integrity TestDPT 1551-51 (method per ASTM D5882-16, withdrawn by ASTM in 2025)
Static Load TestDPT 1251 and ASTM D1143/D1143M-20e1
Cross Hole Sonic Logging (CSL)ACI PRC-228.2 (ASTM D6760 withdrawn in 2025)

Be cautious if a company cannot state the standard number, cites a number that does not match the test method, or uses uncalibrated equipment, as the results may be inaccurate. You can ask to see the calibration evidence for the equipment to be used before hiring.

3. How much real experience and track record do they have?

Experience shows in accurate interpretation and in handling difficult sites. Ask about 3 things: years in operation, number of projects, and types of work done (houses, high-rises, factories, over-water work). Then ask for sample projects or case studies similar to yours. For example, SPN Soil Engineering has been operating for over 20 years and has completed more than 500 projects nationwide, including offshore work.

4. Can the report actually be used for a building permit application?

A good report must be complete and certified by a civil engineer licensed by the Council of Engineers Thailand (COE), so it can support a building permit application with the relevant authorities. Before hiring, ask to see a sample report and check that it includes the engineer's signature, COE registration number, test method details, result graphs and interpretation. See the detailed checklist in What a pile test report should contain.

Good to know

No company can guarantee that results will “pass” or be “certainly approved,” because that depends on the actual pile quality and the judgment of the relevant authorities. The testing company's job is to test to standard and issue a correct report.

5. Do they offer every test method?

A company that offers Seismic Integrity Test, Dynamic Load Test (PDA), Static Load Test and Cross Hole Sonic Logging (CSL) has 2 advantages: it can recommend the method that suits the job, and if preliminary results are questionable it can follow up with in-depth testing within one team, without coordinating several firms. The methods and number of piles to test should be specified by the design engineer.

6. Is the pricing transparent?

Transparent pricing clearly itemizes what is and is not included, such as the test method, number of piles, report and travel. SPN's reference prices per pile are:

  • Dynamic Load Test (PDA): from ~THB 5,500/pile
  • Seismic Integrity Test: ~THB 100–150/pile
  • Static Load Test: THB 50,000–150,000+/pile
Pricing caution

The prices above exclude travel and equipment mobilization, which are charged by distance to the site. A transparent company states this clearly in the quotation rather than adding it later. For other services without fixed prices, you should receive a clearly itemized quotation. See more in Pile testing prices 2026.

7. Do they have availability and cover your site?

Construction schedules are tight, and pile testing often has to happen within a limited window, such as after the concrete reaches the required age. Ask 2 things: how soon a test can be booked, and whether the company works in your site's province. SPN works nationwide in all 77 provinces, covering both urban and provincial sites.

Besides documents, the test day itself is another chance for the client to check with their own eyes. The figure below simulates a site on test day. The circled numbers match the checklist points, such as the calibration tags on the equipment (point 2) and a team that can perform both PDA and Seismic tests (point 5). The panel on the right lists 7 documents to request before hiring.

3D model of a site on pile test day, showing what the client can observe per the 7-point checklist and the documents to request before hiring Conceptual 3D view of a construction yard cut away to show fill and clay layers. On the yard are several neatly trimmed square pile heads. The circled numbers are points of the seven-point checklist. One: an engineer in a white hard hat watches signals on a PDA unit on a folding table, representing the person responsible for the results; ask for the name and COE license number of whoever signs the report. Two: green calibration tags hang on the sensors on the pile head and on the PDA unit. Three: the crew wears PPE, with orange cones and barrier tape around the test point. Four: data from the PDA unit flows into a report with test method, result graphs and interpretation, signed by a COE-licensed engineer. Five: one team performs several methods; in the back is an orange guide frame with a drop weight for a Dynamic Load Test (PDA) on a pile with an extended head, and at front right a technician taps a pile head with a hand hammer for a Seismic Integrity Test (PIT). Six: an equipment truck parked at back left represents the travel and mobilization costs that should be stated in the quotation. Seven: a site calendar sign represents scheduling the test date in the queue after the concrete reaches the required age. The panel on the right lists the documents to request before hiring, in point order: name and COE registration number of the certifying engineer; standards used and equipment calibration evidence; project list or case studies; a sample report; list of available test methods; a quotation stating whether travel and mobilization are included; and the work queue with site date. The bottom panel stresses that no company can guarantee a pass, because results depend on the actual pile quality and the judgment of the relevant authorities. 3D model: what the client can see on test day Not to scale 6 Equipment truck Travel/mobilization must be in the quote 7 Book date in queue once concrete is of age Dynamic (PDA) Drop weight · pt 5 2 Cal. tag on PDA unit + sensors 1 Site engineer Ask name + license no. of report signer 3 Organized crew PPE · cones · tape 5 All-in-one team PDA at back + Seismic (PIT) Tap pile head w/ hammer 4 Full data → report Method + standard Graph + interpretation Signed by lic. engineer Usable for permits Section: fill / clay · conceptual · circled numbers = checklist points Actual site steps depend on test method and project specs Documents to request Number = checklist point 1 Name + COE license no. of certifying civil engineer 2 Standards + calibration DPT/ASTM no. + cal. cert. 3 Projects / case study Types of work done 4 Sample report Method · graphs · interpretation 5 Available methods Seismic · PDA · Static · CSL 6 Itemized quotation Incl. travel + mobilization? 7 Queue + site date Within required concrete age No one can guarantee a “pass” Results depend on pile quality and the judgment of the relevant authorities
A site on pile test day (3D model) — circled numbers are checklist points the client can observe; the right panel lists documents to request before hiring. Actual site procedures depend on the test method and project requirements. (Conceptual image · Image: SPN Soil Engineering)

Why does choosing a pile testing company matter?

Because pile test results are the data engineers use to decide whether construction can proceed or remedial work is needed. If results are wrong or the report is unreliable, there are 2 risks: (1) building on defective piles without knowing it, risking structural settlement; and (2) a report that cannot be used for permits, requiring retesting and costing both time and money. Choosing a company with engineer certification that works to standard is therefore more cost-effective in the long run.

How does SPN Soil Engineering meet the 7-point checklist?

Here is how SPN Soil Engineering compares against the checklist above. Clients should request supporting evidence, just as with any other company.

  • COE-licensed engineer certification (points 1, 4) Reports are certified by a civil engineer licensed by the Council of Engineers Thailand (COE), with signature and registration number, usable for building permit applications.
  • Standards matched to each method (point 2) Dynamic Load Test (PDA) per DPT 1252-51 and ASTM D4945 · Static Load Test per DPT 1251 and ASTM D1143 · integrity testing by Seismic Integrity Test per DPT 1551-51
  • Over 20 years of experience · 500+ projects (points 3, 7) Nationwide service in all 77 provinces
  • Several methods in one team (point 5) Seismic Integrity Test, Dynamic Load Test (PDA), Static Load Test and CSL. See the overview on our pile testing services page.
  • Clearly itemized pricing (point 6) Travel and equipment mobilization are stated in the quotation. Get a free quote within 24 hours.

Summary: what to check before hiring a pile testing company

Before hiring pile testing, check 7 points: certification by a COE-licensed engineer, DPT/ASTM standards and calibrated equipment, experience and track record, a report usable for permits, a full range of test methods, transparent pricing, and availability/service area. Request supporting documents for every point, and remember that no company can guarantee a “pass.” Choosing a company that meets all 7 points makes test results reliable and lets construction proceed with confidence. The same principles apply to choosing a soil boring company.