Samsun · Merkez · 2026
Samsun Piazza — Waterproofing the MV Switchroom Cable Penetrations
In brief
The waterproofing of the cable penetrations into the medium-voltage (MV) switchroom at Samsun Piazza shopping centre was carried out by Zahan İnşaat in 2026. The problem was solved from the outside rather than from within: an excavation was opened along the retaining wall, the zone where the cables enter was sealed with a cementitious waterproofing mortar, a drainage board was applied to the wall face and the backfill was compacted in layers.
- Year
- 2026
- Scope
- Cable penetration sealing and wall waterproofing
- Method
- Excavation, repair mortar, drainage board, compacted backfill
- Location
- Samsun Piazza Shopping Centre
- Structure type
- Medium-voltage (MV) switchroom
- Service line
- Waterproofing and Damp Proofing
Water reaching an electrical room is a safety matter before it is a structural one. When a medium-voltage room takes water the subject is no longer a damp patch but outage and risk to life.
At Piazza the cables passed through the retaining wall and water was coming in at those penetrations. A repair made from inside does not meet the water on the side it arrives from — it has to work in the negative direction. We therefore opened an excavation along the wall and solved the problem from the side the water comes from.
Why excavate from outside?
On a wall retaining earth, waterproofing works when it is applied to the face the water presses against — that is, the outside. An application made from within sits under negative pressure and separates over time.
- The excavation is taken down to the wall footing; the level at which the cables enter is fully exposed.
- Loose concrete is removed from the wall face and the zone around the cable ducts is sealed with a cementitious waterproofing mortar.
- A drainage board (dimpled membrane) is applied to the face — water runs down to the footing without bearing on the wall.
- The backfill is laid in layers and compacted with a plate compactor; if it settles, the board tears.
Working around an electrical room has its own rules
Excavating around an MV room requires the cable route to be known in advance. The final part of the excavation is dug by hand, any outage is planned with the relevant department, and the cables are protected against mechanical damage throughout. This job is a safety plan before it is a waterproofing job.
Site photographs
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Frequently asked questions about this project
Our electrical room takes water — will a repair from inside be enough?
It may dry it temporarily, but it will not solve it for good. Waterproofing works when applied to the face the water presses against; an application from inside sits under negative pressure and separates from the wall in time. The permanent solution is to excavate on the earth side and close the penetrations and the wall face from there.
Is there a solution without excavation?
In some cases a resin injection can close the wall from within; but on crowded, moving penetrations such as a cable bundle, injection does not give a dependable result. The decision is made during the survey, according to the number of penetrations, the wall thickness and the groundwater level.
Can this be done while the shopping centre and its tenants are trading?
Yes. Because the work runs outside the building, in the excavation area, the operation of the centre was not interrupted. The excavation was made safe and separated from pedestrian and vehicle traffic; steps requiring an outage were planned together with the operator.
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Çobanözü Mah. Toybelen Küçük Sanayi Sitesi, Atakum / Samsun
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