Defects in NEN 2767: severity, intensity and extent

A defect is a deviation in a building component that makes its condition worse. Under NEN 2767, you record each defect on three dimensions: severity, intensity and extent. Together, these three determine how urgent the defect is and which score the element receives.

The method is set out in NEN 2767-1 . The list of defects is in NEN 2767-2 . On this page, you can see how to record a defect. The scores that follow from it are on Condition scores 1 to 6.

A defect is not the same as a score. The defect belongs to one place on an element. The score belongs to the element as a whole.

The three dimensions

Each dimension answers a different question. The classes come from the standard. You check the exact boundaries and descriptions in NEN 2767-1.

Dimension	Question you answer	Classes according to the standard
Severity	How serious is the damage?	Minor (aesthetic), serious (degradation) or severe (direct impairment of function)
Intensity	At what stage is the defect?	From initial stage to final stage
Extent	Which part of the element is affected?	Incidental (less than 2%), local (2 to 10%), regular (10 to 30%), considerable (30 to 70%) or general (70% or more)

The extent is the only number of the three. It states what percentage of the element is affected. The other two are the inspector’s judgements, based on the description in the standard.

Example: timber rot on a window frame

Office building Hoogstraat 12 (fictional) has twenty timber window frames on the front facade. The inspector finds timber rot on the bottom sills of five frames. He records the defect as follows.

Choose the element

The element is “timber window frames, front facade”. That is on the element list.

Determine the severity

The rot has already started and is affecting the timber, but the frame can still function. That is serious, a degradation.

Determine the intensity

The rot is already in the timber and is visibly further advanced than an initial stage. The inspector chooses the advanced stage.

Determine the extent

Five of the twenty frames have the defect. That is 25% of the element. In the standard’s classes, that falls under regular.

Record it

The defect is recorded in the report with these four values. That makes the defect traceable and comparable with a next measurement.

Why three dimensions and not one?

A defect can be large and yet not urgent. The reverse can also be true. This example shows that.

Defect A: Minor paint damage across the whole facade surface. Severity minor, intensity initial stage, extent general. It looks big, but it is not urgent.
Defect B: One broken roof tile in one place. Severity severe, intensity final stage, extent incidental. It is only one spot, but water can get in.

With one number for “how bad is it”, you would rate defect A as more serious than defect B. The three dimensions prevent that mistake. That is why you plan on the combination.

How do you record a defect?

A fixed working method makes the measurement repeatable. Any inspector who sees the same defects should arrive at the same record. That is how the method works.

Look up the element on the element list.
Choose the defect from the defects list in NEN 2767-2.
Determine the severity, the intensity and the extent.
Note the four values, and optionally a photo and a short description.
Combine the defects per element into a score.

Step 2 is where mistakes often arise. A defect that is not on the list is not recorded by yourself. Discuss that with the client first.

The defects list as a tool

The defects list is the tool in which you look up the defects per element. That list belongs to NEN 2767-2. Check which version of the standard you are using.

You can work with a spreadsheet or with software. In both cases, it is important that the defects in your tool match the list in the standard. Otherwise, you will end up comparing apples with pears.

Common mistakes

Mixing up severity and urgency. Severity is one of the three dimensions. Urgency comes from the combination.
Recording only the extent. A large defect at an initial stage is different from a small defect at a final stage.
Recording defects per building instead of per element. The element is the unit on which the score depends. A defect belongs to one element.

Frequently asked questions about defects under NEN 2767

Must every small defect be recorded?

That depends on the assignment and the depth of reporting. State in the quote which defects you want to see. The depth of reporting also determines the price. See What does a NEN 2767 condition measurement cost?.

What do I do if a defect is not on the defects list?

Discuss this with your client before you classify it yourself. A defect outside the list makes comparison with other measurements harder.

Is severity the same as urgency?

No. Severity is one of the three dimensions. Urgency comes from the combination of severity, intensity and extent. A severe defect at a final stage can be more urgent than a larger defect at an initial stage.