Decide whether the mark interrupts the waterproofing
A tiny dark point in a cured waterproof coating can be a shallow surface crater, an exposed substrate pore or an opening through the waterproof layer. These appearances can look similar in a photograph. The first decision is therefore whether the membrane remains continuous, followed by how widely the condition occurs and whether the surrounding coating is properly bonded.
For a Cyprus property owner, the practical concern is accepting a repair that addresses the defect rather than simply hiding its appearance. An extra coat may be appropriate in one situation and unreliable in another. Its usefulness depends on why the holes formed, whether the existing film can be retained and how the repair will bond to that cured surface.
Avoid testing a suspected hole by pushing a sharp object through it. That can create or enlarge a defect and destroy useful evidence. Photograph representative areas with a scale, identify the coating if possible and preserve the installation records before cleaning or repairs alter the surface.
Map the pattern before assigning a cause
The distribution often helps frame the investigation. Holes concentrated over porous concrete suggest a different line of enquiry from defects following reinforcement overlaps or one application strip. Marks confined to a patched area may relate to that substrate or its preparation. These patterns are clues for testing, not proof of a single cause.
Concrete outgassing is one documented mechanism. The Sikalastic-590 product data sheet explains that air escaping from concrete can produce pinholes in subsequently applied coatings. It calls for assessing moisture, air entrapment and surface finish, and notes that stable or falling concrete temperature can reduce outgassing during application.
A contractor should also examine preparation, application thickness, reinforcement saturation and material handling against the actual system instructions. Do not label every defect outgassing because the roof was warm. The explanation should account for where defects occur, where they do not occur and what the installation evidence shows.
Check the cured film and the base separately
The assessment should record whether the coating is cured, soft, blistered, peeling or otherwise inconsistent. Surface continuity and adhesion are separate properties: a film can appear continuous while poorly attached, or remain firmly attached around isolated openings. Repairing the visible holes alone addresses neither widespread loss of adhesion nor a deficient underlying base.
Ask how thickness will be established. Material quantities and application records provide useful context, but an average consumption calculation can conceal thin areas and heavy local build-up. Any direct thickness examination should suit the membrane and substrate, with destructive sample locations agreed and repaired afterwards.
Where an electrical continuity test is proposed, require confirmation that the system, substrate and test method are suitable. Conductive layers and the roof build-up affect what can be detected. A report should state the tested area and limitations. A clean result from an unsuitable method is not meaningful evidence that the waterproofing is continuous.
Compare quotations using the same repair boundary
Two quotations described as pinhole repair can purchase substantially different work. One may cover a few marked points, another may coat an entire roof, and a third may remove defective material first. Compare what each method assumes about adhesion and thickness, how it treats the cured surface and what evidence it will provide afterwards.
| Proposed scope | When it may merit consideration | What must be resolved |
|---|---|---|
| Local compatible repair | Isolated openings within otherwise acceptable film | Defect depth, sound surrounding material and approved overlap |
| Prepared-area recoating | A wider continuity issue with a retainable coating | Preparation, recoat bond and specified finished build-up |
| Removal and reinstatement | Poorly bonded or otherwise unsuitable coating | Removal boundary, substrate treatment and replacement system |
| Further investigation | Cause or extent remains uncertain | A defined test question and how its result changes the scope |
The table is a comparison framework, rather than an installation specification. Require bidders to describe the same roof areas and exclusions. The existing guide to choosing a waterproofing specialist helps with that broader comparison; pinhole work additionally needs explicit continuity and recoat checks.
Resolve the mechanism before repeating the coating
If porous substrate remains exposed after defective coating is removed, the replacement method should address those pores before the waterproofing is reinstated. Simply repeating the previous application can reproduce the same defects. The appropriate pore treatment, primer and waterproof layer must belong to a supported system.
Sika's Sikagard P 770 guidance provides a specific example: it describes pore sealing and a scratch-coat option for rough concrete or pinhole filling within its approved applications. This does not make that primer a universal filler for holes in already cured roof membranes.
For retained coating, ask the manufacturer to confirm cleaning, abrasion or activation requirements and any primer needed after the normal recoat interval. A product bonding to fresh material is not sufficient evidence that it will bond to an exposed, weathered film. Keep the proposed trial area representative of the actual repair conditions.
A hypothetical comparison between two affected areas
Consider a hypothetical villa roof with scattered pinholes across one recently coated concrete bay and a few similar marks near a previously repaired outlet. The manager initially requests one price for another coat over everything. Inspection instead treats the two patterns as separate questions.
In this example, the concrete bay has numerous through-openings but acceptable surrounding adhesion; the outlet patch shows local detachment. Subject to manufacturer confirmation, prepared-area recoating might be evaluated for the bay, while the detached patch requires removal to a sound boundary and rebuilding of its connection. Using one method everywhere would either omit necessary work or remove material without justification.
The decision record should explain the evidence behind each boundary. If a trial recoat develops further holes, work pauses to revisit preparation or substrate conditions. A successful-looking wet application is insufficient: the trial must reach the relevant inspection stage before it supports the wider repair.
Agree acceptance evidence before covering the defects
A useful repair agreement identifies the inspection conditions, the areas receiving close visual examination and any additional continuity testing. It should distinguish cosmetic texture from unacceptable openings using the selected system's requirements. Avoid inventing a universal allowable number of pinholes per square metre; that would sidestep whether the waterproofing is actually continuous.
Record preparation, products, application dates and repair locations. Where testing identifies defects, retain the original result together with the subsequent repair and recheck record. This makes it possible to distinguish an unresolved area from one that was repaired and verified. It also gives the next maintenance contractor a usable history.
If pinholes have appeared after recent work, request an assessment of the waterproofing detail with wide photographs, close photographs and the coating documents. The immediate objective is a supported decision about retention, repair and verification, so that a visually improved roof is also assessed against its waterproofing purpose.
Frequently asked questions
Does every visible pinhole cause a leak?
A surface crater may not pass through the waterproof layer. The depth and continuity need assessment; appearance alone cannot establish whether a water path exists.
Can I solve pinholes by applying a thicker coat?
Only if the selected system supports that repair and the retained coating is suitable. Excess thickness does not correct poor adhesion or an unresolved substrate problem.
Is late-afternoon application always the answer?
No. Falling substrate temperature can help reduce concrete outgassing in the cited system, but dew point, weather, cure conditions and other causes still matter.
Should pinhole repairs include a flood test?
Not automatically. Any water testing needs a defined purpose and consideration of the structure, drainage, occupied spaces and membrane requirements.
Sources
Sources checked 2026-10-15.