Roof terrace and penthouse finishing

Waterproofing first: water and heat

Any roof finish starts with waterproofing and heat insulation, because a leak found after the tiles are down means lifting everything above it.

1. Inspect the slab

   Check the slab, its cracks and where the drains are, and remove any old layers that are no longer sound.

2. Falls

   A screed laid to gentle falls towards the drains, so water never stands anywhere on the roof.

3. Waterproofing

   A continuous waterproofing layer over the whole roof, turned up the parapet walls and sealed carefully at the drains and around every pipe that comes through.

4. Heat insulation

   Insulation boards that cut the heat reaching the floor below, which makes a real difference in summer.

5. Flood test

   Before any tile, the roof is flooded and left for a day or two, and the ceiling below is checked.

6. Protection layer

   A layer that protects the waterproofing from knocks and from the sun before the floor finish goes on.

The exact order of the layers depends on the waterproofing system used. What matters is that each layer is checked before the next one covers it.

Loads and drainage before decoration

Before you add large planters, a jacuzzi or new walls on a roof, a structural engineer should confirm the slab can carry the weight.

• Wet soil in planters is heavy, and a filled jacuzzi weighs far more than it looks.
• Brick walls and any new structure add a permanent load to the slab.
• Drains must stay open and easy to clean, never buried under flooring or decoration.
• Pergola and canopy posts are fixed with a detail that does not puncture the waterproofing, or are sealed carefully around it.
• Water, drainage and power routes for an outdoor kitchen are decided before the waterproofing, not after.

Floors that can take the sun

The best roof floor is light in colour and slip-resistant, because direct sun heats dark colours and smooth surfaces are slippery when wet.

Pergolas: timber, steel or aluminium

No material wins in every case: the choice depends on the look, the upkeep you are willing to do, and how close you are to the sea.

Wind on a roof is stronger than at ground level, so any pergola or canopy needs fixings that are calculated, not just a few screws into the tiles.

Outdoor kitchen and seating

Outdoor kitchen tops on a roof must take direct sun, and granite suits better than quartz here, because quartz can change colour in strong sunlight.

• A sink with a properly connected drain, and a supply valve that can be closed for winter.
• Cabinets in outdoor-rated materials or steel and stainless steel, not indoor boards.
• A barbecue placed so smoke does not blow towards the neighbours or the windows.
• Built-in seating with storage underneath for cushions in winter.
• Enough shade over the seating, because a roof without shade cannot be used by day in summer.

Electrics and outdoor lighting

Roof electrics should be treated as outdoor work: light fittings and sockets made for rain and dust, on circuits protected by an earth-leakage breaker.

• Sockets with tight covers, away from where water collects.
• Separate circuits for lighting, the outdoor kitchen and any jacuzzi.
• Layered lighting: soft general light, light on paths and steps, and light for planting.
• Spare conduit for speakers, a screen or cameras you may want later, instead of breaking the floor open again.

Additions and the rules

Building a room or any enclosed space on a roof is building work, and building work needs a licence from the relevant authority; in a compound, the developer's approval as well.

Even a fixed pergola or canopy may be restricted by compound rules or by the building's own agreement, so ask the management or the owners' association and get the answer in writing before the design starts.

Do not rely on anyone's word that something is "normally fine". Ask the authority or the management directly.

How Itmam finishes a roof

We visit the roof, check its condition and measure it, then write you an itemised quotation before any work starts, with the waterproofing, the floors, the pergola and the electrics listed as separate items.

Pergola frames, railings and other metalwork come from our own workshop, and granite and stone tops are templated, cut and installed by the same team.

On the North Coast we use the coastal specification: seaside-class powder coating, 316 stainless fixings and hot-dip galvanised steel.

On a finishing contract you pay the suppliers directly and the tax invoice is in your name.