Dubai Hills Estate villa owners are settling in and upgrading. The three jobs we’re asked about most are extensions, rooftop solar and new routes through the roof slab. All three need holes through concrete, and each one comes with its own risks.
Here are the questions Dubai Hills Estate homeowners ask most, answered plainly.
Extensions
Does an extension need core cutting?
Usually, yes. Extensions often need new drainage, AC, electrical and water routes from the existing villa into the new space. Those routes pass through existing walls or slabs, which means cores.
Can I core through the wall between the villa and the extension?
It depends on what the wall is. Many villa walls are blockwork, which is straightforward to core. Some are reinforced concrete or carry load from above. Check the drawings, and if the wall is structural, get an engineer’s approval before any holes go in. Our structural analysis team can confirm.
Is drilling for dowel bars the same as core cutting?
No. Dowel bars that tie a new slab into an existing one are usually set in smaller drilled holes, not cores. But the same rule applies: scan first so the holes don’t hit existing rebar or services.
What approvals do I need for an extension?
Expect a developer or community NOC for the design, and an authority permit for the construction. Core cutting is part of that approved work, so it shouldn’t start before approvals are in place. See our permits and approvals service if you need help.
Solar cabling
Why does rooftop solar need core cutting?
Solar panels on the roof produce power that has to reach the inverter and your electrical board, usually inside the villa. The cables need a route down, and that often means a core through the roof slab or an external wall.
Rooftop solar is growing fast in Dubai. By mid-2025, DEWA’s Shams Dubai programme had connected more than 725MW of rooftop solar across over 8,430 buildings (MESIA, citing DEWA).
How big is the hole?
Solar cable routes usually run in conduit. A 25 to 32mm conduit typically needs a core of about 38 to 52mm. If your installer wants spare capacity, go one size up.
Who decides where the hole goes?
Your solar installer plans the route, but they should agree the core position with whoever does the coring. Rooftop solar in Dubai needs a DEWA-certified installer, so check their drawings before coring.
Can the cables go down an existing route instead?
Sometimes. If there’s a spare service route or an existing riser, use it. Fewer new holes in the roof means fewer places for water to get in.
Roof slab coring
What’s actually on top of my roof slab?
Usually several layers: a slope screed, insulation, a waterproofing membrane and sometimes tiles or a protection layer. A core cuts through all of them.
Will a roof core leak?
Not if it’s sealed properly. Leaks happen when the waterproofing isn’t restored around the new pipe or conduit. Use a proper roof penetration detail, such as a sleeve with a collar that bonds to the membrane, and seal it before the next rain.
How do you stop water from coring getting into the villa?
The crew uses water to cool the bit, so they collect it at the top with a ring or wet vacuum. They should also protect the ceiling and furniture in the room below.
Can you core near roof beams?
The core must stay clear of beams unless an engineer approves it. Roof beams carry the roof and any plant, tanks or panels on top of it.
Do I really need to scan a roof slab?
Yes. Roof slabs carry rebar and often conduits for lights, CCTV and roof equipment. GPR concrete scanning marks them and also measures slab thickness, which the crew needs to know before drilling.
Before the crew arrives
- Have your NOC and any permits ready
- Share the solar or extension drawings
- Clear the room below roof cores
- Tell the crew about any existing leaks or past repairs
Book core cutting in Dubai Hills Estate
Scan and Core handles villa core cutting across Dubai, including extensions, solar routes and roof slabs. We scan, core and leave the roof sealed and clean. See our concrete cutting and coring services.
Contact Scan and Core to book a visit, or call +971 56 861 9006.
