Dilapidation Survey Report: Crack Classification, Monitoring and Vibration Limits

01What a Dilapidation Survey Report Is For

Pre-, During- and Post-Construction Surveys

• Pre-construction survey: sets the baseline.
• Interim surveys: during the works, these track change at the points most likely to be affected.
• Post-construction survey: repeats the baseline so each item can be compared like for like.

What It Can and Cannot Show

The report records condition and change. It does not, on its own, prove what caused a change. BS 7385-2 notes that cracking is common in buildings whether or not they are exposed to vibration, and that cracks are not, in themselves, an indication of vibration-induced damage [1]. Malaysian studies have documented cracking in existing buildings near new works, which is exactly why a clear baseline matters [2].

02When It Is Required in Malaysia

DBKL’s 2022 Guideline

DBKL’s Panduan Pengemukaan Laporan Dilapidasi di Wilayah Persekutuan Kuala Lumpur (2022) sets out the Kuala Lumpur requirements [3]:

• When it is required: the dilapidation report on adjoining lots is a Development Order condition. It must be submitted before Borang B, before earthworks or building works start.
• Where it goes: to DBKL’s Jabatan Perancangan Infrastruktur and Jabatan Kawalan Bangunan, with copies to affected owners.
• Who endorses it: a registered building surveyor, architect or engineer.
• Inspection height: at least 10 m above ground.
• Basements: all levels.
• Strata buildings with a JMB or MC: common areas only.
• Report format: photographs presented in set formats, and defect descriptions that include crack length and width.

DBKL also sets minimum study zones:

Zones are measured from the site boundary, to the front, rear and sides.

The guideline allows wider zones where needed. For deep basements, engineers often check the zone against one to two times the excavation depth. That is engineering practice, not a DBKL rule. For more detail, see our guide to DBKL dilapidation report zones of study.

Other Local Authorities and the DOE Guideline

• Outside Kuala Lumpur: a dilapidation survey is often imposed as a planning or building-plan condition. Check your approval letter for the exact wording.
• DOE guideline: the Department of Environment’s Guidelines for Environmental Vibration Limits and Control (3rd ed., 2021) recommends dilapidation surveys before, during and after construction or demolition, together with vibration monitoring [4].

In short, a dilapidation report is required by DBKL and recommended by DOE.

03How Cracks Are Classified in a Dilapidation Report

BRE Digest 251 Damage Categories

BRE Digest 251 (revised 1995) is the scale most often used for masonry and plaster [5]:

Three caveats from the Digest itself:

• The categories are based on ease of repair, not on width alone.
• They were written for low-rise buildings with masonry walls and finishes. They are not a measure of damage to reinforced concrete members.
• They describe damage, not its cause.

For RC elements, report widths are compared with the design crack limits for concrete, around 0.3 mm for most exposures. For the causes behind common crack patterns, see cracks in walls.

What to Record for Every Crack

• a unique ID tied to a floor plan or elevation
• location, orientation (vertical, horizontal, diagonal or stepped) and pattern
• length and maximum width, measured with a crack-width gauge card or crack microscope
• whether it is through-wall, and the substrate (plaster, brick, concrete)
• BRE category, a photograph with a scale, and a note on any staining or displacement

04Crack Monitoring Methods

Choosing a Method

Reading Frequency and Trigger Levels

• Reading frequency: follows the works. Readings are more frequent during excavation, piling or demolition next to the property, then less frequent.
• Trigger levels: set per project by the engineer, usually as an alert level (look again and review) and an action level (notify, inspect and consider changing the works).
• Temperature: in Malaysia’s climate, small daily and seasonal movements are normal. Readings are taken at a similar time of day and compared with the overall trend, not with one reading.

Worked Example: A 12-Week Tell-Tale Log (Mock Data)

Illustrative only. The readings are mock data. The trigger levels are example project values set by the engineer, not limits from any standard. No standard sets alert or action levels for crack monitoring. BRE Digest 251 classifies damage by crack width, and triggers are set in each project’s monitoring plan.

A tell-tale is fixed across a stepped crack in the party wall of a terrace house next to a basement excavation. It is read with callipers on its measuring studs, to 0.1 mm. Example triggers set by the engineer for this project: alert at 0.5 mm and action at 1.0 mm of movement from the baseline, or any new crack of 0.3 mm or more. These are small compared with the BRE Digest 251 crack-width categories (Category 1 is up to about 1 mm), so the response starts while any change is still slight.

How to read the log: the recorded movement increased during the excavation stages and showed no further change after week 10. It stayed below the action line. The report records the trend, the response at each trigger and the latest reading. It does not draw conclusions about cause beyond what the record shows.

05Vibration Limits: BS 7385-2, DIN 4150-3 and the DOE 2021 Guideline

BS 7385-2:1993

BS 7385-2 gives transient vibration guide values at the building base, below which cosmetic damage is unlikely [1]:

Where vibration is continuous, as with vibratory piling or sheet-pile driving, the values may need to be reduced by up to 50%.

DIN 4150-3:2016

DIN 4150-3 is more cautious, especially for sensitive structures [6]. Short-term limits at the foundation:

For the horizontal vibration of the topmost floor, the limits are 40, 15 and 8 mm/s for lines 1, 2 and 3.

The DOE 2021 Guideline

The DOE guideline brings these references into Malaysian practice [4]:

• Fifth Schedule: limits for continuous vibration, for example 25 mm/s for framed buildings.
• Sixth Schedule: BS 7385-2 values for intermittent vibration, such as impact piling, demolition and breakers.
• Eighth Schedule: DIN 4150-3:2016 values, applied to single-event impulsive vibration such as blasting.
• Ninth Schedule: BS 5228-2 human perception levels (0.14, 0.3, 1.0 and 10 mm/s) [7].

Building damage limits and human comfort are different questions. Residents can feel vibration far below the levels that risk cosmetic damage.

Choosing a Criterion

• Ordinary residential and commercial neighbours: BS 7385-2, as adopted in the DOE guideline, is the common starting point.
• Heritage, fragile or sensitive buildings: DIN 4150-3 line 3.
• Building type: the choice follows the building, its condition at baseline and the type of works. It is stated in the monitoring plan before work starts.

06Vibration Monitoring in Practice

• Instrument: a tri-axial geophone, calibrated annually, measuring PPV and frequency on three axes.
• Mounting: rigidly fixed at foundation level on the side facing the works, as BS 7385-2 and ISO 4866 recommend [8].
• Alerts: readings are checked against the set trigger levels, and every exceedance is reported the same day.
• Records: monitoring files are kept with the dilapidation report, so vibration and crack readings can be compared side by side.

Our guide to vibration monitoring and structural dynamics explains the physics in more depth.

Worked Example: Piling 15 m From a Brick Terrace (Planning Only)

Illustrative planning example. No measured vibration data is shown, and the trigger levels are example project values, not limits from any standard.

A new commercial block needs piling 15 m from a row of two-storey brick terrace houses.

1. Zone. If the block is classed as large under DBKL’s Lampiran I categories, the minimum zone is 30 m from the site boundary, and the terrace is well within it. Its baseline survey covers all accessible rooms and elevations, to at least 10 m above ground.
2. Criterion. The terrace is unreinforced masonry, so the plan adopts BS 7385-2’s residential line: 15 mm/s at 4 Hz, rising with frequency. If vibratory or continuous methods are used, the plan applies the continuous-vibration reduction, or the DOE Fifth Schedule values.
3. Triggers. No standard sets alert or action levels; they are project values agreed in the monitoring plan. A common practice is to set them as fractions of the applicable guide value at the dominant frequency, measured at the base of the nearest property. Two levels are set, alert and action, and the engineer and contractor agree in advance what happens at each.

Lower values are used where the survey finds significant existing structural defects. For a sensitive or heritage building, the DIN 4150-3 value of 3 mm/s below 10 Hz is the reference instead.

1. Prediction. BS 5228-2 Annex E gives empirical formulas to estimate PPV from piling energy and distance [7]. These are screening estimates, so monitoring is still needed.
2. Response. If readings approach the action level, the options include changing the piling method or sequence, or pre-boring, as agreed in the plan.
3. Record. Monitoring results and interim crack readings are kept with the dilapidation file.

Malaysian field research has shown that vibration from piling at very close range can be significant, which supports monitoring the nearest structures first [9].

07What a Good Dilapidation Report Contains

1. Scope. The property list, zone, dates, weather and access status for each property.
2. Access refusals. Owners are typically notified in writing, for example by registered post, about 14 days before the visit, and any refusal or no-response is recorded for each property.
3. Element-by-element record. Photographs with references, crack IDs, measurements and BRE categories.
4. Monitoring points. The location and baseline reading of each tell-tale, gauge or geophone.
5. Comparison codes for later surveys. NC (no change), EXT (existing defect extended), NEW (new defect) and REP (repaired since the last visit).
6. Limitations. Visual and non-invasive; concealed areas not inspected; a record of condition on the date stated, with no view on cause unless separately investigated.
7. Endorsement. By a registered building surveyor, architect or engineer, as DBKL requires. Our reports are endorsed by a Professional Engineer with a Practising Certificate (PEPC).

Frequently Asked Questions

08Plan Your Dilapidation Survey With Us

Starting works next to occupied buildings? Our engineers can scope a dilapidation survey with crack and vibration monitoring to match your approval conditions. We cover Kuala Lumpur and Shah Alam and Klang. WhatsApp us at wa.me/60168064902, call +60 16-806 4902 or email inspectsolution.pro@gmail.com.